Vihvelin.com

Presented at “Free Will Physics and Metaphysics” conference. Rutgers University, May 12^th,2022

Co-author Terrance Tomkow

Abstract

Causation requires (at least the possibility of) contingent counterfactual dependence between events at different times. Contingent counterfactual dependence requires logically irreversible laws connecting those events. But logically irreversible laws only give you contingent counterfactual dependence in one direction. Thus, contingent counterfactual dependence between events is temporally asymmetric. Our actual laws are logically irreversible. Thus, causation is temporally asymmetric.

 

&;

Why Time Has a Direction

with Terrance Tomkow

Abstract

The direction of causation is the direction of contingent counterfactual dependence.   The temporal asymmetry of counterfactual dependence gives causation its temporal direction.  That asymmetry is explained by the fact that the dynamical laws of nature are logically irreversible functions from partial states of the world onto other partial states.   Though these irreversible laws are locally indeterministic, they sum to global determinism.  This combination of global determinism and local indeterminism gives rise to counterfactual asymmetry and gives causation and time a direction.  That direction is independent of the direction of entropy.   The direction of contingent counterfactual dependence-- and hence causation--  is time's arrow.

nb. Originally posted as Irreversible Laws and the Direction of Time on 11/10/2018

Causation

with Terrance Tomkow

Abstract
Causation is defined as a relation between facts: C causes E if and only if C and E are nomologically independent facts and C is a necessary part of a nomologically sufficient condition for E. The analysis is applied to problems of overdetermination, preemption, trumping, intransitivity, switching, and double prevention. Preventing and allowing are defined and distinguished from causing. The analysis explains the direction of causation in terms of the logical form of dynamic laws. Even in a universe that is deterministic in both temporal directions, not every fact must have a cause and present facts may have no future causes.

 

Killing Time Again

Abstract

I have argued that even if time travel is logically possible, there are some things a time traveler would not be able to do.  I reply here to critics who have argued that my account entails fatalism about the past or entails that the time traveler is unfree or that she is bound by “strange shackles.” My argument does not entail any sort of fatalism. The time traveler is able to do many of the things that everyone else can do and is as free as any non-time traveler. The time traveler is constrained only as we all are by the laws of nature. My argument shows only how strangely those constraints must operate if those laws permit time travel.

Forthcoming in The Monist: Abilities and Control,  Helen Beebee and Ann Whittle eds., June 2020

The Temporal Asymmetry of Counterfactuals

Determinism

with Terrance Tomkow

Despite its central role in so many philosophy disputes-- or perhaps because of it-- there is widespread confusion about what ‘determinism’ means.

Certainly the standard textbook definitions are wrong. Wrong in the way that definitions are wrong: they don't capture what anyone really means by the term.

On the standard definitions to say that a world is deterministic is to say that:

"Determinism is quite simply the thesis that the past determines a unique future… it is the thesis that there is at any instant exactly one physically possible future."  Van Inwagen

"…determinism says that, given the state of the world at any particular time, the laws of nature determine all future developments, down to the last detail. Another convenient way of putting the thesis is this: a complete description of the state of the world at any given time and a complete specification of the laws of the nature together entail every truth as to what events happen after that time."  Ginet

Determinism is the thesis that a complete statement of a universe’s natural laws together with a complete description of the condition of the entire universe at any point in time logically entails a complete description of the condition of the entire universe at any other point in time. Mele

…determinism is the thesis that the precise state of the Universe at any moment( a billion years ago, or five seconds ago or whatever, together with the laws of nature, determines the precise state of the Universe at any other time (999 million years ago, in one seconds time or in another 999 million years time). To put it even more precisely, let Pt be a statement that describes the exact state of the whole Universe at a particular time t, and let L be statement that describes all the laws of nature. Then Pt & L logically entail a statement that describes the exact state of the Universe at any other time. Hence if someone knew all the facts about the state of the Universe at a given moment, and they knew all the laws of nature, then they would be able to predict with certainty what the state of the Universe will be in, say, ten seconds’ time. Beebe

…determinism is the thesis that for every instant of time t, there is a proposition that expresses the state of the world at that instant, and if P and Q are any propositions that express the state of the world at some instants… the conjunction of P together with the laws of nature entails Q.  Vihvelin

Determinism requires a world that (a) has a well-defined state or description, at any given time, and (b) laws of nature that are true at all places and times. If we have all these, then if (a) and (b) together logically entail the state of the world at all other times (or, at least, all times later than that given in (a), the world is deterministic. Logical entailment, in a sense broad enough to encompass mathematical consequence, is the modality behind the determination in 'determinism'.  Hoefer 

And so on.

To see what's wrong with this, consider this simple, logic circuit world

W1

 

Possible world W1 is governed by the simple law:

L1  It is nomologically necessary that: A iff (B v C)

We can describe all the worlds that are nomologically possible given this law with a simple truth table

		A	B	C
	W4	T	T	T
	W3	T	F	T
	W2	T	T	F
	W1	F	F	F

W1 is deterministic according to the standard definitions. It has laws "true at all places and times". It has only one nomologically possible future given its initial condition. Its laws are not probabilistic. Given its laws and given a description of the total state of W1 at t1, we can accurately deduce the total state of the world at t2. Indeed, W1 is, on the standard definition, deterministic in both temporal directions: given the total state W1 at t2, and L1, we can deduce the state of the world at T1.

But W1 isn’t really deterministic in the sense that anyone intends.

Of course, given that A is false at W1 we know given L1 that both B and C must be false. But L1 does not require that A is false. So what would happen if A were true at W1? Would B be true, or C or both?

Notwithstanding W1’s simplicity and the clarity of its laws, there is obviously no determinate answer to these questions.

We can infer the actual future of W1 from its actual past but that we can do so is an accident of what is actually true in it. We could not predict its future if it’s past were different; different in ways its laws permit. Which is why no one would call W1 “deterministic”. Indeed W1 could serve as a poster child for what everyone means by 'indeterminism'.

To capture what we mean we have to amend the definitions. We need to say that a deterministic world is not just one whose laws entail its actual future given its actual past but one in which a unique nomologically possible future is entailed by every nomologically possible past and a unique past by each nomologically possible future.

John Earman gets it right,

Letting W stand for the collection of all physically possible worlds, that is, possible worlds which satisfy the natural laws obtaining in the actual world, we can define the Laplacian variety of determinism as follows. The world W ϵ W is Laplacian deterministic just in case for W’ ϵ W, if W and W ’ agree at any time, then they agree for all times. By assumption, the world-a-a-given-time is an invariantly meaningful notion and agreement of worlds at a time means agreement at that time on all relevant physical properties. This concept to determinism can be broken down into two subconcepts. A world W ϵ W is futuristically (respectively, historically) Laplacian deterministic just in case of any W’ ϵ W, if W and W ’ agree at any time then they agree for all later (respectively, earlier) times. A Primer on Determinism, p.13.

Why do so many get it wrong? We think it not so much a matter of carelessness but as the upshot of a kind of philosophical wishful thinking. The wish is that the “nomological” in nomological determinism would go away. Recall Hoefer’s claim that:

"Logical entailment, in a sense broad enough to encompass mathematical consequence, is the modality behind the determination in 'determinism.'"

Hoefer wants the only kind of necessity involved in determination to be logical. He wants to see the determination of facts as simply a matter of their entailment by the more general truths we call “laws”. But determination means more than that. When we speak about determinism we suppose not just that there are laws of nature that describe general truths about the way world is but that they also, somehow, circumscribe the ways the world can be.

Unsurprisingly, David Lewis gets the definition right:

A deterministic system of laws is one such that, whenever two possible worlds obey the laws perfectly, then either they are exactly alike throughout all of time, or else they are not exactly alike through any stretch of time. They are alike always or never. They do not diverge, matching perfectly in their initial segments but not thereafter; neither do they converge. Let us assume, for the sake of the argument that the laws of nature of our actual world are in this sense deterministic.  Lewis 

By explicitly quantifying over nomologically possible worlds, Lewis captures the modal commitments the standard definitions overlook. His definition makes clear how much we are assuming when we assume for the sake of any philosophical argument that determinism is true.

And yet we contend that even Lewis does not get determinism right. Lewis gets it wrong because he has other metaphysical doctrines that prevent him from properly understanding the implications of determinism.

Counterfactual determinism

Here, across the centuries, two great systematic metaphysicians directly contradict each other.

“… ultimately, because of the connection of things, the whole universe with all its parts would be very different, and would have been a different one from the beginning if the least thing in it went differently from how it does go. On account of this, it is not the case that events are necessary, but it is the case that they are certain, given the choices that God made of this possible universe, whose concept contains this sequence of things.” Leibniz

“Under determinism any divergence… requires some violation of the actual laws. If the laws were held sacred, there would be no way to get rid of e without changing all of the past; and nothing guarantees the change could be kept negligible except in the recent past. That would mean that if the present were ever so slightly different, then all of the past would have been different—which is absurd. Lewis

 

Leibniz is asserting counterfactual determinism.

Counterfactual Determinism
However the world happens to be: If the world had been different in any respect at any time then it would have been different in some respect at every moment in the future and the past.

Lewis accepts that nomological determinism entails counterfactual determinism going forward. That is, he agrees that, in a deterministic world, if things were different at any time they would be different at every time thereafter. And he does not deny that, in a deterministic world, if things were different now then things would typically have to be different in the recent past. What he denies is that the past would have to be different at every moment. This denial is a direct consequence of his account of counterfactuals.

When we evaluate a counterfactual of the form:

If A had been the case at t1 then C would have been the case at t2

We consider whether C is true at worlds like ours at which A is true. But because Lewis does not “hold the laws sacred”, he doesn’t think that we are constrained to consider worlds that obey the laws of the actual world. Indeed, Lewis supposes that, if the actual non-A world is deterministic, then the closest worlds where A happens will always be ones in which A is the upshot of “miracle” -- an event contrary to the laws of the actual world-- which occurs at or shortly before t1. The histories of such worlds—the way things would be if A-- are exactly like ours right up until the moment of the miracle.

For Lewis, “Backtrackers”-- counterfactuals which assert that the remote past would have been different in some non-miraculous respect if the present were otherwise-- are always false.

But Lewis’ theory is not the only one on offer. In past posts we have argued for a different theory: Jonathan Bennett’s Simple Theory of Counterfactuals.

Bennett’s theory does “hold the laws sacred”. It holds that when we evaluate

If A had been the case at t1 then C would have been the case at t2

we must restrict ourselves to considering only nomologically possible worlds at which A is true. If the world is nomologically deterministic, in the modally relevant sense, it must be that every nomologically possible world has a different past and future than every other nomologically possible world. If worlds diverge at any time, they must diverge at every time. If that is so then the closest nomologically possible A world must always be one which differs from the actual world at every moment.

Thus Bennett’s theory vindicates Leibniz: Nomological Determinism entails Counterfactual Determinism. And that, we submit, is yet another argument in favor of Bennett’s Simple Theory.

Counterfactuals: The Short Course

with Terrance Tomkow

Consider this possible world. 

w1

It’s a world in which signals appear at the left at time t1 and emerge on the right at t2. The dark circles indicate the presence of a signal; an empty circle, the absence.

w1  is a very simple world. It is governed by one simple law.

(L1)    It is nomologically necessary that: (A and B) ≡ C

We can describe its workings with a simple truth table using T or F to indicate the presence or absence of a signal.

 

 The rows represent all the combinations of events that the Law (L1) permits. They don't represent all logically possible worlds, only the nomologically possible worlds given (L1).

If you think there is something fishy about circuit diagrams.  note that we can build a world which is exactly like w1 for all our purposes out of  billiard balls:

 

A Billiard Ball AND Gate

 

 The simplicity of L1 makes the nomological logic of w1 easy. For example, from L1 we can infer derivative laws like:

(L1')    It is nomologically necessary that: ~A ⊃ ~C

The counterfactual logic of w1 is also simple. Consider, for example, the question "What would have happened at w1 if ~A (that is, if there had been no signal on A)?”  The obvious answer is that in that case there would have been no signal at C:

~A > ~C

At first glance, it might seem that we can read the truth of this counterfactual directly off L1 by way of L1'.  But counterfactual reasoning is not that simple. To see this, think of one of the possible worlds where A and C are both false:

w3

Ask yourself: "What would happen at w3 if A were true?"  The correct answer seems to be that, in this situation, if A were true, then C would also be true.

A > C

After all, since B is already true at w3, all that is required to make C true, according to L1, is that A be true. And yet that conclusion is not entailed by L1 all by itself. In fact L1 entails:

It is not nomologically necessary that if A ⊃ C

The moral is that to decide if a counterfactual is true we must pay attention not only to the laws but also to the facts on the ground. A counterfactual can be true at one world but false at another. Thus in this situation:

w4

it is not true that A > C.  In this world B is false and just making A true would not, according to L1, be sufficient to make it the case that C. So:

A>C is true at w3

A>C is false at w4

This relativity of counterfactual truth to worlds makes the logic of counterfactuals more complicated than the strict conditionals we study in introductory logic classes. So complex that it was only in the 1970's that philosophers — the seminal figures here are David Lewis and Robert Stalnaker — got a grip on it.

Lewis and Stalnaker's central insight was that the truth of counterfactuals turns on relations of similarity between worlds. We say that a counterfactual of the form:

If ANTECEDENT were the case, then CONSEQUENT would be the case.

is true at a world if the worlds most similar to it at which ANTECEDENT is true are worlds at which CONSEQUENT is also true. Those in the know will recognize what we oversimplify here. It makes no difference to what follows.*

Thus, to return to our example,  w1:

w1

and w2:

w2

are the nomologically possible worlds where the antecedent, A, is true:

But w2 is dissimilar to w3 in a way in which w1 is not.  At w2, B is false whereas at both w1 and w3, B is true. This makes w1 more similar to w3 than any other world at which A is true. And because C is true at this closest world, A > C is true at w3.

Pretty much everyone who thinks about counterfactuals agrees that this is a fruitful way to understand their logic, but it still leaves open issues. These centrally devolve around the question of how to measure similarity. w1-w4 are so simple that they don't leave much room for debate: we can count similarities by counting signals. But we do not have to make things much more complicated for deeper questions to emerge.

Consider this world.

w1’

The new branch is captured by the additional law:

(L2) It is nomologically necessary that: C ≡ D

So the nomologically possible worlds look like this.

Now consider the question: "At w1', what would have happened if C had been false?"

The obvious answer seems to be that if C had been false then D would have to be false given (L2).  Moreover, if C had been false then either A or B would have to have been false since (L1) entails:

(L1')  It is nomologically necessary that: ~C ≡ ~( A & B)

Which means that by the measure of counting signals there is a tie among ~C worlds closest to w1'. A tie between

w2’

and

w3’

We capture ties like this in our ordinary subjunctive speech by talking about the way things "might have been". We say that if C were false at w1' then either A or B might have been false.

But already our similarity measure might seem to fall short of capturing everything we want to say. Ordinarily we would say that if ~C, then A might be false or B might be false or both.  But the simple signal counting method excludes that third option, w4'

w4’

because w4’ is more dissimilar to w1' at t1 than either w2' or w3'. 

This seems odd.  Our simple counting method seems to require us to say that if C were not true then one of A or B would be false but not both.

Here it is natural to look to David Lewis for guidance. But when we do, we get a surprise.

On Lewis's account, none of w2', w3' or w4' is the right answer to the question “What if ~C?”.  According to Lewis the most similar world to w1' at which C is false is:

w*

Now you might well protest that w* is not a nomologically possible world given L1 and L2.  But Lewis thinks that is beside the point.  Lewis says that when we think counterfactually we are not obliged to confine ourselves to nomologically possible worlds.  We are allowed to think of worlds that violate the laws, worlds that contain “miracles”.

On Lewis's account, when we compare worlds for similarity:

1. It is of the first importance to avoid big, widespread, diverse violations of law.
2. It is of the second importance to maximize the spatiotemporal region throughout which perfect match of particular fact prevails.
3. It is of the third importance to avoid even small, localized, simple violations of law.
4. It is of little or no importance to secure approximate similarity of particular fact, even in matters that concern us greatly.
   

At w*, C is false even though both A and B are true. This is a violation of L1. A miracle. But the required miracle does not seem "widespread or diverse" in the sense prohibited by Lewis’s requirement (1).  A single "small and localized" failure in the AND gate or in any one of several connections would do the job. In the billiard ball example: a tiny diversion of the course of a single ball at any point.

w2’,  w3’ and w4’ involve no violations of law, but Lewis ranks that consideration, (3), as less important than (2): maximizing the extent of spatiotemporal overlap between worlds. In that respect, w* beats w2’-w4’ hands down.

In treating w* as closest, Lewis denies the backtracking counterfactual.

~C > ~(A & B)

This is "backtracking" because its antecedent is about a time later than its consequent. This is not an anomalous result for Lewis's theory. It was Lewis’s official position that counterfactual backtracking was always a bad business and that most backtrackers are false.  This prohibition against backtracking was centrally important to his metaphysics and is widely accepted even by metaphysicians who disagree with Lewis on other points.

And yet in the context of our simple worlds the refusal to backtrack is simply absurd. Any electrician who reasoned like this would soon be out of a job. In these simple worlds, if C were false then either A or B or both would have to have been different.

Let us hasten to say that we  have not come this far just to offer a contrived counter-example to Lewis.  One can imagine any number of arguments to the effect that Lewis is not committed to this absurd result in these cases or that the results are not absurd in these cases or that these examples are anyway not relevant to "real world" counterfactuals.  We will not join those arguments here.

Tomkow has already devoted a lengthy post to arguing against Lewis's theory. There he argued that the correct account is Jonathan Bennett's 1984 "Simple Theory".

Bennett's Simple Theory doesn't trade in miracles: It requires that we find the closest worlds among nomologically possible alternatives. It holds that a counterfactual is true at a world if its consequent is true at the nomologically possible worlds most similar to it at the time of the antecedent.

To see how that plays out in the case of w1': Note that all the nomologically possible alternatives to W1' where C is false are equally similar and equally dissimilar to w1' at the time of C, t2.  All that happens, or fails to happen, at any of these worlds at t2 is C or ~C.  On Bennett's theory, any similarities or differences among these worlds at any time before or after t2 are irrelevant to closeness. Only similarity at the time of the antecedent matters. The upshot is that Bennett's account will treat w2', and w3' and w4' as equally similar to w1'. Thus Bennett allows us to say, as we wanted to say, that if C had been false at w1' then either ~A or ~B or both ~A and ~B.

These simple cases illustrate the merits of Bennett’s theory over Lewis's. Though simple, we think them profoundly important. 

Lewis was a great philosopher, but his theory of counterfactuals was a disastrous misstep.  Lewis’s miracles theory disconnects counterfactual possibility from nomological possiblity at the most fundamental level. It requires us to regard counterfactual reasoning as inherently different from scientific reasoning, to treat metaphysics as disjoint from physics. 

Bennett’s theory can mend this divide because it describes direct connections between laws and counterfactuals. In forthcoming posts we will try to show that these connections have much to tell us about the nature of causation, events, and the arrow of time.  

Dispositional Compatibilism

Dispositional Compatibilism

We believe that we have free will, and this belief plays a central role in how we think about ourselves and about our lives. Free will matters to us, and not just because we think that having free will is a necessary condition of being morally responsible. Free will matters to us because having some say in the overall shape of our lives matters to us. We want to develop our skills and talents as best we can, make the most of our opportunities, and live the best lives it is in our power to live.

We know that there are severe limits to the control that we have over our lives. What we are able to achieve depends not only on us, but on our surroundings. We know that luck plays an enormous role, and we know that the playing field is not level. And even if we are fortunate in our starting point -- in our native endowments, our parents, social class, and so on -- we know that unforeseen events and the actions of other people can frustrate our plans and thwart our hopes. Knowing this, we might wonder how far our abilities extend, how much we are truly able to do. We might wonder whether we are really able to do, or even try to do, all the things we think we are able to do. We might worry that our powers of imagination are too limited, preventing us from even considering some of the things we might otherwise be able to choose and do. And so on.

But we don't doubt that we have free will. What we do is not the only thing we can do. The choices we make are not the only choices in our power to make. We are able to think for ourselves, whether or not we actually do so. We are able to try to do lots of things, whether or not we actually do try. We have abilities we don't exercise, perhaps some abilities we never exercise. We don't have to do what we do. We are able to do otherwise. Or so we believe.

We also believe that we often use or exercise our free will -- we take a moment to think before we act; we decide what to do, and then we act. And while we are sometimes in a position where we make a choice while being mistaken about what our options are, this is not always the case. Ordinarily, when we make a choice we really do have the choice we think we have. You are, right now, able to continue reading this essay, and you are also, right now, able to stop reading. Take a moment to consider these options. Then decide. Welcome back!

There is more to our view of ourselves as free agents than the belief that we have real choices and genuine alternatives, but this belief is at the core of our commonsense view of ourselves as persons with free will. If we were somehow convinced that we never really have a choice about what we do, we would conclude that our belief that we have free will is either outright false, or, at best, that we are radically mistaken about the nature of our free will.

We can agree about this while leaving other questions up for grabs. Do we have a choice only on those occasions when we deliberate, weigh our reasons, make a decision, and then act, or do we also have a choice when we act spontaneously, or on the basis of a hunch, or on the basis of what feels right or seems obvious? Do we have a choice in cases of coercion, and other cases when we have "no real choice" or "no reasonable choice"? What about cases where making a particular choice would go so deeply against our values that it is, in some sense, unthinkable for us? These are questions about which reasonable people may disagree.

We can also leave open questions about the exact relationship between choice and moral responsibility. We can all agree that moral responsibility doesn't require having a choice at the time of action -- we blame a drunk driver for the accident she causes, even if she wasn't able, at the time of the accident, to do otherwise. But does it require having a choice, at some earlier time, between sets of reasonably foreseeable outcomes of one's action? Or is it enough, so far as moral responsibility is concerned, that a person had a choice, at some time in the past, about the actions which led, eventually, to the formation of her present character? Again, these are questions about which reasonable people may disagree.

The answers to these questions are important, but irrelevant so far as the problem of free will and determinism is concerned. For determinism appears to have the consequence that it is never true that anyone has a choice of any kind -- big or small, important or trivial. If we choose to lie, we could not have chosen to tell the truth. If we choose the scenic mountain road, we could not have chosen the freeway. If we choose the apple, we could not have chosen the orange.

Roughly stated, determinism is the conjunction of two claims: i) that we are no exception to the fundamental laws that govern everything else in the universe; ii) that these laws state sufficient (as opposed to merely necessary or probabilistic) conditions for the occurrence of every event. More precisely, determinism is the thesis that, for every time t, the laws together with some proposition about the state of the universe at that time, entail the state of the universe at every later time.

Determinism is not part of our commonsense view.1 But as soon as we understand what the thesis of determinism says (and why it is a live possibility that determinism, or something close enough, is true), we see the problem. For if determinism is true, it seems that whatever happens must happen. And if that's true, then it seems that it must also be true, on each and every occasion, that what we do is the only thing wecan do. We are never able to do otherwise, or even choose or try otherwise. And if that's so, then our belief that we have free will is an illusion.

The free will/determinism problem is the problem of deciding whether this apparent bad consequence of determinism really is a consequence. Suppose that scientists announce that they have discovered irrefutable evidence that the thesis of determinism is true. Would this mean that our belief that we have free will is false?

The commonsense compatibilist² says "no". The incompatibilist says 'yes'.

The libertarian incompatibilist goes a stepfurther and says that we don't need to worry about this hypothetical scenario because we have good reason to believe two things: First, we really do have free will. Second, it's not possible both that we have free will and that determinism is true. Therefore, we've got good reason to believe that determinism is false, and, moreover, false in just the right way to provide the kind of "open" future needed for free will.

Which of these two competing views -- libertarian incompatibilism or commonsense compatibilism³ -- should we believe?

We might start by noting that the two views are not on a par. The libertarian view has commitments that the compatibilist view does not. Both sides agree that we have free will, and both sides agree that we often also have what is sometimes called freedom of action; we are able to choose otherwise and also to act on the basis of that choice. But the compatibilist says that the truth of this commonsense belief is not hostage to what future science might tell us about the fundamental laws, whereas the libertarian says that it is. And the libertarian also claims that our reasons for believing that free will is incompatible with determinism are so good that we are justified, on the basis of our current evidence, in believing that determinism is false in just the right way. This seems dubious. So it seems that the commonsense compatibilist starts off with an advantage, at least against the libertarian. The commonsense compatibilist might insist, therefore, that since she and the libertarian agree about the free will claim, the libertarian needs an argument to defend her incompatibility claim.

The Dispositional Compatibilist provides a further, positive argument for commonsense compatibilism by showing how our commonsense beliefs about free will are compatible with our beliefs about the natural world and our place in it, in a way that is not contingent on the falsity of determinism.

There are different ways of being a Dispositional Compatibilis ⁴, but what all varieties of Dispositional Compatibilism (DC) have in common is that they claim that the most fundamental free will facts are facts about our causal powers (for instance, our power to decide on the basis of deliberation) and that our causal powers differ in complexity but not in kind from dispositions like fragility, elasticity, and flammability. In the older literature a distinction was sometimes drawn between "active" and "passive" powers -- the active power "exerted" by the rock when it breaks a window, the passive power manifested by the window when it is broken. The contemporary literature does not recognize this distinction, and neither does DC. The claim is that all dispositions -- of natural objects, artifacts, and human beings -- are causal powers with the same kind of causal structure. How exactly that structure should be understood is the subject of much metaphysical debate. But the main point, so far as DC is concerned, is simple. We think that determinism is incompatible with free will because determinism seems to have the consequence that we have no power over anything, not even our own choices. But if our causal powers are dispositions, this is not true. For dispositions are uncontroversially compatible with determinism. And dispositions are real properties of their bearers; they don't cease to exist simply because they are not being manifested. A rock doesn't lose its window-breaking power just because it isn't currently breaking windows. A person doesn't lose her decision-making power just because she isn't currently making a decision. Nor does she lose her power to decide to do one thing just because she makes another decision instead.

Can the solution to the free will/determinism problem really be so simple? Let’s take a closer look.

Dispositions and Abilities

 

Let's begin by considering some features of dispositions.

When we attribute a disposition to an object, we do so on the basis of a counterfactual property that we associate with objects which have that disposition. For instance, the counterfactual property that we associate with fragile objects is the property of being such that if the object were dropped or struck, it would break. But an object might have the counterfactual property associated with a disposition without having the disposition. A sturdy concrete block on the edge of the roof of a twenty story building has the property of being such that if it were dropped, it would break. But the concrete block is not fragile. And an object may have a disposition without having the counterfactual property that we associate with that disposition. A crystal glass doesn't cease to be fragile when it is carefully wrapped in styrofoam, but once it is thus protected it no longer has the property of being such that if it were dropped, it would break.

Why do we say that the protected glass is fragile but the precariously perched concrete block is not?

First approximation: Because the glass is the kind of thing that breaks easily, in a wide range of circumstances; the concrete block is not. A bit more precisely, the glass shares some intrinsic property with other fragile objects (glasses not wrapped in styrofoam), many of which have the counterfactual property. By contrast, the concrete block's possession of the counterfactual property is a highly extrinsic property; if the block is moved closer to the ground it loses this property.

It turns out to be surprisingly difficult to make these intuitive ideas more precise⁵, but here is a rough characterization of what it is for something to be fragile: An object is fragile just in case it has some intrinsic property or set of properties P such that if the object were dropped while in the right surroundings (intuitively, those surroundings that count as providing a test for the disposition: no protective packing, from a moderate height, onto a hard surface, and so on), its being dropped and its having P would together cause its breaking. Because this intrinsic property figures in this way in the manifestation of the disposition, we call it the causal basis of the disposition.

More generally, to have a disposition is to have a certain kind of causal power -- a causal power which an object has by having some intrinsic property that serves as the causal basis of the disposition.

The key claim of DC is that our abilities, including the abilities in virtue of which we have free will, are dispositions, with the same kind of causal structure. But before we get to free will, let's take a look at some less controversial examples of human abilities: the ability to walk, walk a straight line, play piano, fall asleep as soon as your head hits the pillow. Let’s call these kinds of abilities 'ordinary abilities'; think of them as abilities to move your body in certain kinds of ways or abilities to cause certain kinds of changes in your body. These abilities are structurally like dispositions in the following ways: We have them by having certain intrinsic properties that are the causal basis of the ability (e.g. we have the ability to walk by having unbroken legs and certain other properties of our brain and nervous system) and we don't lose them simply because our surroundings have changed. (You might object that the shackled prisoner is no longer able to walk, and there is a sense in which this is true. But the sense in which it's true is the sense in which the styrofoam-packed glass is no longer able to break.) Finally, while our abilities are relatively stable properties, they can be lost (and sometimes regained) in the same way that an object can lose (and sometimes regain) a disposition. A wet match is no longer flammable; a melted glass no longer fragile. You lose your ability to walk when you break your legs, your ability to walk a straight line when you drink too much, your ability to fall asleep as soon as your head hits the pillow when you drink a cup of coffee just before going to bed.

Some philosophers think that our powers and abilities are fundamentally different from dispositions and capacities because they think that the manifestations of dispositions and capacities are caused "willy-nilly"⁶ by environmental stimuli whereas it is up to us whether we exercise our abilities. There is some truth to this, but we need to be careful. First, note that one of the abilities I listed -- the ability to fall asleep as soon as your head hits the pillow -- is exactly like the dispositions I've discussed insofar as its manifestation is caused, "willy-nilly" by the environmental stimuli of your head being on the pillow. Despite this, we call it an ability, and it’s a valuable ability to have. Second, it isn't true that the manifestations of dispositions are always caused by environmental stimuli. An animal's disposition to search for food is manifested in response to the internal stimulus of the animal's hunger. The ability to play piano is an ability that we exercise in response to the internal stimulus of trying to play. And other abilities have other kinds of internal stimuli. The ability to fall asleep by doing long division with your eyes closed is an ability you exercise in response to the internal stimulus of doing long division with your eyes closed.

To sum up: Our ordinary abilities are dispositions. These abilities are intrinsic in the same way that dispositions are intrinsic: to have one of these abilities is to have some intrinsic properties that are the causal basis of the ability; so long as you retain these properties, you retain the ability. Sometimes our surroundings prevent us from exercising one of our abilities in the way that styrofoam packing prevents a fragile glass from breaking. But this isn't always or even typically the case. Often we fail to do something we have the ability to do simply because we don't try to do it. On these occasions we have both the ability and the opportunity to do other than what we actually do.

Dispositional Compatibilism

Dispositional Compatibilism is the name for a family of views. I will give a brief sketch of how I understand the view.

The most fundamental free will facts are facts about some bundle of abilities in virtue of which we think and deliberate and make decisions and choices and form intentions about what to do. Let's call this bundle of abilities 'the core free will bundle'. So long as we retain this core bundle, we retain free will, even if we are prevented, by unfortunate surroundings or loss of ordinary abilities, from moving our bodies in the ways we try to move them.

There is lots of room for argument about what abilities are required in order to have the core free will bundle, but the following are relatively uncontroversial parts of the package: the ability to form and revise beliefs on the basis of evidence and argument; the ability to deliberate for the purpose of deciding what to do in response to one's intention to so deliberate; the ability to decide what to do in response to one's trying, by deliberating, to do so.

The abilities that are part of this bundle are all dispositions.

In addition to the abilities which constitute the core free will bundle, we have various other abilities, including the ability to act on the basis of our decisions and the ability to act on the basis of intentions which are simply acquired,withoutbeing the product of any prior mental action. These other abilities are part of the free will we think we have (when we think, for instance, that having free will gives us some say in the overall shape of our lives).

These abilities are also dispositions.

We have the free will we think we have, including the freedom of action we think we have in situations where we make a choice between courses of action that are genuine alternatives for us, by having some bundle of abilities and being in the right kind of surroundings -- the surroundings that are test cases for the relevant dispositions.

For instance, while typing this paragraph, I considered whether to stop and go to the kitchen for a cup of coffee. After thinking about it briefly, I decided not to, and went back to typing. Suppose that this is the kind of normal case where I really did have the choice I thought I had. I was free to decide and act as I did and also to decide and act otherwise. It was up to me what I did.

On my view, these commonsense beliefs are true in virtue of the facts about my abilities and my surroundings. I was free to decide otherwise because I had and exercised the ability to decide, on the basis of deliberation, whether to get the coffee or continue typing. (I wasn't in the grip of any compulsive desire or subject to a post-hypnotic command, or anything else that deprived me of this ability to decide, nor was there anything in my surroundings that would have somehow prevented me from exercising this ability.) I was free to act otherwise - to get the coffee -- because I had the ability to walk and because my surroundings were favorable. (I wasn't shackled, the door wasn't locked, there really was coffee in the kitchen, and so on.)

Having some such bundle of dispositions, together with suitably friendly surroundings, suffices for our having the free will we think we have. Perhaps something else might also suffice -- some power of agent-causation that's not a disposition. But such agent-causal powers, if they exist, are not needed for free will. And the falsity of determinism is also not needed, for it is no part of this story. If you think it is needed, you need an argument. It's hard to see what could count as an argument, since dispositions don't cease to exist simply because they aren't being manifested, and since having the ability to decide whether to do something is an ability that, by its very nature, is exercised either by deciding to do that thing orby deciding not to do that thing.

Could it be argued that if determinism is true, then our surroundings are always unfavorable, robbing us of the opportunity to exercise any unexercised ability? I don't think so. While it is possible that a person is always in surroundings which prevent her from exercising one or more of her abilities in the way that the styrofoam prevents the fragile glass from breaking, determinism doesn't have this consequence. What determinism does entail is that if we don't exercise one of our abilities there was some sufficient cause of our not doing so. But it doesn't follow that our surroundings always fail to provide what's needed for a test of one of our unexercised abilities. Sometimes we don't exercise an ability simply because the stimulus event does not occur. To claim that the non-occurrence of the trying (or other stimulus) counts as a deprivation of opportunity is to reject the claim that our abilities are dispositions. Perhaps that's right, but in the absence of any other account of what our free will powers are, DC stands unrefuted.

Objections:

In this section I will respond to three objections to DC.

First objection: Having free will can't be a matter of having any disposition(s). Even if there is a sense in which a lump of sugar is able to dissolve, it isn't up to the sugar whether it dissolves. Nor is it up to a car whether it starts or up to a computer whether it runs one program or another.

Reply: Having a mind is a necessary condition of having free will. Lumps of sugar, cars, and computers don't have minds.

Second objection: A dog has a mind and has dispositions, not only to behave in various ways, but also to make certain kinds of choices. But a dog doesn't have free will.

Reply: The case of dogs is less clear than it seems. If we deny free will to dogs, we must also deny it to babies and young children, and commonsense is conflicted on this point. But I'm inclined to agree that dogs and babies lack free will. DC has the resources to say the right thing, which is that we acquire free will gradually as we acquire more sophisticated abilities, including abilities to make increasingly complex choices. We learn to do things with our bodies before learning to do things with our minds, and we acquire the abilities that ground our freedom of action before we acquire the abilities that ground our free will.

The third objection is one that was widely accepted as a refutation of an older dispositional account - the Conditional Analysis.⁷ According to the Conditional Analysis, a person is able to do X just in case it's true that if she tried (chose, decided, etc.) to do X, she would. Here's an example of the kind of case that, everyone agreed, was a decisive counterexample to the Conditional Analysis.

Clea is an excellent cyclist, but she had a bad accident and now has a pathological fear of bike-riding, so she isn't able to try to ride her bike. But since she is in perfect physical condition she would succeed in riding if she tried. (Or so it is claimed.) We are supposed to agree that Clea isn't able to ride her bike. But the Conditional Analysis says that she can, so the Conditional Analysis is false.

Does this case refute DC?

I don't think so. The case is underdescribed, but on two plausible versions of the story, DC can say the right thing.

First version. Clea's phobia is so extreme that she won't calm down even if she somehow manages to get on her bike (perhaps with a little help from her friends). She'll panic and lose control of the bike. In this case, she lacks two different abilities -- a volitional ability and also an ordinary ability. She lacks the ability to try to ride and she also lacks the ability to ride. It isn't up to her whether she rides.⁸

Second version. Clea's accident left her with a phobia that is purely volitional in this sense -- she isn't able to try to ride. But if she somehow did try -- if she found herself in the saddle with her legs making, or beginning to make, the first bike-pedaling motions, her fears would melt away and she would be her old bike-riding self again.

In this case, we should say that she has the kind of ability to ride that a puppy has to chase its tail and a baby has to crawl in the direction of a bright and shiny object. She's got the ordinary ability to ride, but she lacks the second order ability to cause herself to exercise this ability (by reminding herself of her resolution to overcome her fears, taking a deep breath to calm herself, and so on). She can't make herself ride; it isn't up to her whether she rides.

Conclusion

 

We've got the free will we think we have, including real choices and genuine alternatives, by having a certain bundle of abilities (dispositions) while being reasonably fortunate with respect to our surroundings.We may continue to have free will despite losing many abilities and despite being very unfortunate in our surroundings. But determinism robs us neither of free will nor freedom of action.

References

Davidson, Donald, 1973. "Freedom to Act". In Essays on Freedom of Action, ed. by Ted Honderich. Routledge and Kegan Paul.

Fara, Michael, 2008. "Masked Abilities and Compatibilism". Mind 117: 843-865.

Frankfurt, Harry, 1971. "Freedom of the Will and the Concept of a Person". Journal of Philosophy 68: 5-20.

Graham, Keith, 1972. "Ifs, Cans, and Dispositions". Mind 14: 186-199.

Hobart, R.E, 1934, "Free Will as Involving Determination and Inconceivable Without It". Mind 63: 1-27.

Lewis, David, 1997. "Finkish Dispositions". Philosophical Quarterly 47: 143-158.

Manley, David, and Wasserman, Ryan, 2008. "On Linking Dispositions and Conditionals". Mind 117: 59-84.

G. E Moore, 1912. "Free Will". In Ethics. Oxford: Oxford University Press.

Perry, John, 2004. "Compatibilist Options". In Freedom and Determinism, ed. by J. Campbell, M. O'Rourke, and D. Shier. Cambridge, MA: MIT Press.

Smith, Michael, 1997. "A Theory of Freedom and Responsibility." In Ethics and Practical Reason, ed. by G. Cullity. New York, NY: Clarendon Press.

Smith, Michael, 2004. "Rational Capacities". In Ethics and the A Priori: Selected Essays on Moral Psychology and Meta-Ethics. New York, NY: Cambridge University Press.

van Inwagen, Peter, 1983. An Essay on Free Will. Oxford: Clarendon Press.

Vihvelin, Kadri, 2004, "Free Will Demystified: A Dispositional Account". Philosophical Topics 32: 427-450.

Vihvelin, Kadri, 2008. "Compatibilism, Incompatibilism, and Impossibilism", in Contemporary Debates in Metaphysics, ed. by Sider, Hawthorne, and Zimmerman, Malden, MA: Blackwell Publishing.

Vihvelin, Kadri, 2011. "How to Think about the Free Will/Determinism Problem". In Carving Nature at its Joints. Contemporary Philosophy Series, vol. 8, ed. by Campbell and O'Rourke, Cambridge, MA: MIT Press.

Vihvelin, Kadri, 2013. Causes, Laws, and Free Will: Why Determinism Doesn't Matter, New York, NY: Oxford University Press.

 

 

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[1] Our commonsense beliefs about causation and law are vague, as are our beliefs about truth and time. We think of the future as "open" and "up to us" in some sense that contrasts with the "necessity" or "fixity" of the past, and determinism seems to be incompatible with this. But commonsense does not recognize some key distinctions -- in particular, the distinction between the claim that the future is determinate, in the sense that there are true propositions about the future, and the claim that the future is determined, in the sense that there are, in the present, sufficient causes of future events.

[2] Not all compatibilists are commonsense compatibilists. Some are "revisionary compatibilists". Others are "semicompatibilists" who say that determinism rules out free will but is compatible with moral responsibility. For discussion of semicompatibilism, see Chapter .

[3] These are not the only possible views. The hard determinist says that determinism is true, and because of this we have no free will; the impossibilist says that free will is impossible, at least for human beings, regardless of the truth or falsity of determinism. But hard determinism and impossibilism are almost impossible to believe, except when doing philosophy. (Vihvelin 2008.)

[4] Moore 1912, Hobart 1934, Graham 1972, Davidson 1973, Smith 1997 and 2004, Fara 2008, Perry 2004, and Vihvelin 2004, 2011, and 2013. Frankfurt famously denies the relevance of alternatives to moral responsibility, but he also claimed, in Frankfurt 1971, that freedom of will is logically independent of freedom of action and made some remarks which suggest that this is because he thinks that the disposition which grounds freedom of action is distinct from the disposition which grounds freedom of will.

[5] For discussion of some of the difficulties, and two very different accounts, see Lewis 1997 and Manley and Wasserman 2008.

[6] van Inwagen 1983, pp. 10-11.

[7] Moore 1912, Graham 1972, Davidson 1973.

[8] On this version of the case, the Conditional Answer gives the right answer since if Clea tried to ride, she would fail.

How Not to Think about Free Will

We've got free will. I'm able to raise my arm -- I just did. Now I'm not doing it. But I'm still able to do it. And it isn't just true that I'm able to raise my arm even when I'm not raising it; it's also true that I'm able to choose to raise my arm even when I'm not choosing to do it. And the same goes for lots and lots of other things that we don't do but can do. We are able to do much more than we actually do. We have unexercised abilities, unexercised powers of causing -- call them powers of agent-causation, if you want to give them a fancy name. We are able to make choices, on the basis of reasons and reasoning, whether or not we actually do so. We are able to try to do lots of things, whether or not we actually do try. We are able to acquire new beliefs,even if we are too lazy to do the reading or thinking to do so. We are surrounded by unactualized possibilities; we have abilities we don't exercise (perhaps some abilities we never exercise). We don't have to do what we do. We are able to do otherwise.

I take this to be a fact. Call it 'the Free Will fact'. No one denies it. Well, not quite. It's one of those facts of commonsense that no one denies until they start doing some philosophy.

Some say that the Free Will fact isn't compatible with the existence of truths about the future. They say that if it was already true last week -- or last month, or last year, or ten billion years ago -- that I would fly to Flint and give this talk today, then that's something I had to do. I never had a choice; I was never able to do otherwise. That's a mistake -- and is generally agreed (by philosophers, at least) to be a mistake -- the fatalist's mistake.

Others say that the Free Will fact is not compatible with determinism.They say that if determinism turned out to be true, this ordinary fact would not be a fact. Some say that we are entitled to conclude that determinism must be false, and must be false in quite specific ways to give us the "elbow room" or the "leeway" or the "robust alternative possibilities" needed for free will. Others think we have no right to reason from a commonsense belief to the falsity of something that science tells us (or at least might tell us). But they also assume that the truth of determinism is incompatible with the Free Will fact.

But is the Free Will fact really incompatible with determinism? This I take to be the problem of free will and determinism. It's a problem that's been around for quite awhile, as you all know. I claim, in my book, Causes, Laws, and Free Will: Why Determinism Doesn't Matter (OUP 2013), to have solved it. (In case it isn't obvious, I am a compatibilist.) I'm not going to talk about that today.

What I want to talk about is something that comes under the heading of methodology-- I want to talk about how we should think (and talk and write) about free will. But since my time is very short, I will focus on the negative. I will begin by saying how we should not think (or talk or write) about free will. Think of these as Rules for the free will philosopher.

First Rule: Stick to the subject -- free will. Don't start talking about something else instead. Don't start talking about moral responsibility. Free will is necessary, but not sufficient, for moral responsibility. Free will is common -- wise people have it, foolish people have it, some say that babies and many nonhuman animals have it. Moral responsibility is not so common -- no one thinks that babies are morally responsible and there is lots of controversy about when adults are responsible, and more controversy about whether anyone is ever responsible, or whether the concept of moral responsibility even makes sense. But most of this controversy has nothing to do with free will. We might agree that everyone in this room has free will and would have free will even if determinism turned out to be true. It would not follow that any of us is morally responsible or even that it is possible for anyone to ever be morally responsible for anything. So let's keep this firmly in mind, when we talk about free will, and not slip into those dangerous phrases like "moral freedom", or "the free will that grounds or justifies or suffices for moral responsibility".

Or, at least, let's avoid talking in these ways if we hope to make any progress in figuring out what to say about the problem of free will and determinism.

Second Rule: Avoid thought experiments.

Don't get me wrong. Thought experiments are often a useful tool -- sometimes a thought experiment is just what's needed to correct a mistake based on failure of imagination.

For instance, if someone says that you must be awake to be morally responsible, then we can show this false by telling a story about a night watchman who falls asleep on the job, so a burglary occurs on his watch. He was asleep when it happened, but he is still responsible because he could and should have been awake. This is a successful thought experiment but note that it has two ingredients -- we can all understand what is being described and we all agree about the verdict. It works because it spells out a possibility we had not thought of, or had forgotten about. (It's a counterexample.)

A more complicated example of a good thought experiment is the story that Sydney Shoemaker told to refute the claim that there can be no time without change.  Shoemaker told a story about a possible world in which there are three distinct regions, each of which experiences a local freeze (a yearlong period when there is no change) at regular intervals. And because the freezes happen in a regular pattern for the entire history of that universe, there is good inductive evidence that every sixty years there will be a global freeze. This is a good thought experiment because it is perfectly clear what is being described, and because the story makes us aware of a possibility that, until Shoemaker described it, had not occurred to us.

Unfortunately the free will literature is filled with example of bad thought experiments.

Manipulation Arguments are bad thought experiments. These are stories in which we are invited, say, to imagine people who are "just like us" except that everything they think and do is "remote controlled" by evil neuroscientists. They come in different varieties, but they all suffer from the problem of under-description. It is not at all clear what we are being asked to imagine. And they suffer from the problem that people disagree about the verdict -- they haven't changed the minds of any compatibilists. So what exactly is the point? Perhaps to make vivid to the uninitiated what a deterministic universe is like? But we don't need a story about manipulation to do that. Whenever I teach my semester long course on Free Will and Determinism, I succeed in depressing my students for several weeks when I tell them what the thesis of determinism is and gradually convince them that they can't just dismiss it, that its truth -- or something close enough -- is a live possibility. Why are they depressed? Because they think that determinism rules out free will. That, I believe, is a mistake; others disagree. But that's what we should be talking about -- whether determinism really has this bad consequence.

Frankfurt's alleged counterexample to the Principle of Alternate Possibilities is another example.  In Frankfurt's story there is a mysterious character who, we are told, can prevent you from doing or deciding anything you might do or decide. But, in fact, he doesn't interfere with you because he happens to approve of what you do. In that case Frankfurt thought you must still be responsible because no one interfered with your doing what you wanted, even if you couldn't have done otherwise.

Frankfurt's story was supposed to undercut the traditional debate about whether determinism robs us of free will by convincing us that the ability to do otherwise isn't, after all, necessary for moral responsibility.  His story didn't work, so his friends and supporters told other stories and an entire literature of "Frankfurt style-examples" sprung up and has lasted more than 40 years, with no signs of stopping or even slowing down. I have argued in print, more than once, that the stories don't work, that they are underdescribed thought experiments and that when you look more closely at the details, the subject of the stories never loses the ability to do otherwise. No one has said what's wrong with my argument. The response is always -- but, wait, here's another story.

However, it doesn't really matter whether I am right or wrong.  The point is simpler. Frankfurt stories fail the two requirements on being a good thought experiment: that we all know what is being described and we agree about the verdict. A counterexample either works or it doesn't. If you have to spend 40 years arguing about whether a counterexample works, your thought experiment is a failure.

You might think, at this point, that this is just a problem for 'Armchair Philosophy', and that the fix is to leave the armchair and to run some actual experiments.

But the questions that are used by the Experimental Philosophers include their own thought experiments, which are no less murky.

Here is a typical question:

Imagine a universe (Universe A) in which everything that happens is completely caused by whatever happened before it. This is true from the very beginning of the universe, so what happened in the beginning of the universe caused what happened next, and so on right up until the present. For example one day John decided to have French Fries at lunch. Like everything else, this decision was completely caused by what happened before it. So, if everything in this universe was exactly the same up until John made his decision, then it had to happen that John would decide to have French Fries.

Now imagine a universe (Universe B) in which almost everything that happens is completely caused by whatever happened before it. The one exception is human decision making. For example, one day Mary decided to have French Fries at lunch. Since a person's decision in this universe is not completely caused by what happened before it, even if everything in the universe was exactly the same up until Mary made her decision, it did not have to happen that Mary would decide to have French Fries. She could have decided to have something different.

The key difference, then, is that in Universe A every decision is completely caused by what happened before the decision—given the past, each decision has to happen the way that it does. By contrast, in Universe B, decisions are not completely caused by the past, and each human decision does not have to happen the way that it does.

Which of these universes do you think is most like ours? (circle one)

What is the question that is being asked? Do all the phrases used -- "completely caused", "had to happen, given the past", "could not have decided anything different" mean the same thing? Do the people reading this questionnaire understand what these things mean? Are they all thinking about the same thing when they answer these questions? Are some of them perhaps thinking -- as the move from "had to happen, given the past" to 'had to happen" and "could not have decided otherwise" suggests -- of a world where there is no free will?

In the absence of any answers to these questions, these supposedly scientific thought experiments are no better than the Armchair variety.

Again,this isn't an argument against thought experiments in general. Nor is it necessarily an argument against thought experiments about free will. But the Rule, for free will philosophers, is this: Unless you know exactly what you are doing, and are sure you can do it well, avoid thought experiments (and avoid experimental philosophy).

Third Rule: Intuitions. Avoid them! Or if you find that you cannot avoid them because all around you philosophers are appealing to intuitions, and arguing on the basis of their intuitions, and urging you to share their intuitions, constructing thought experiments designed to get you to have more intuitions, or writing up questionnaires for non-philosophers so we can have "data" about intuitions that are not confined to the intuitions of an elite group of philosophers, then I say "just don't do it."

 Why not?

Because intuitions have no special evidential status, qua intuition. Why would anyone think they do? And how did all this talk of philosophical intuitions get going in the first place? This is relatively recent.

Intuitions are just a kind of belief and we don't think that beliefs per se have any special evidential status.

Again, I'm not saying it's always wrong to appeal to intuitions. Some kinds of belief are more epistemically trustworthy than others, and this may be true of some intuitions as well. Some people are very good at judging what other people are thinking and feeling simply by reading their faces and body language. Others -- the autistic and aspergerish -- are not so good. These kinds of intuitions don't have any philosophical payoff. But perhaps there are categories of philosophically relevant intuition which are highly reliable. One possible example might be beliefs about causation in particular cases. We have lots of daily experience of causation so maybe our intuitions about causation are a trustworthy source of data to constrain our philosophical theorizing.

But free will intuitions are very different from intuitions about causation.

In the case of causation, we have daily experience of particular cases that count as causation and cases that don't. We can tell the difference between one thing following another by co-incidence, and the first thing causing the second. In the case of free will, however, the clear contrast cases are few and far between. We have free will; rocks and plants don't. We are able to make choices we don't actually make and to do things we don't actually do. But beyond these clear starting points, things get confused and unclear very quickly. We all have free will -- at least everyone in this room does.  But when did we acquire it? At birth? When we learned to crawl, to talk, to ask questions, to argue with our parents? Or, as some of my students tell me, when we left home to go to university? Do we have free will all the time, or only some of the time? Do we have free will when we are asleep? Under the influence of alcohol or drugs? When we are in a state of panic or severely depressed? Do cats have free will? Might some form of artificial intelligence have free will? When I ask my students these questions, they tell me that they have never thought about these things before, and many of them change their minds about the answers over the course of the semester.

When it comes to questions about free will and determinism, we have a positive reason to distrust our intuitions. Here's why. It's well known, in philosophy, that the fatalist is confused. Truth isn't the same as necessity, of any kind. The fact that there are truths about my future choices and actions does not affect my freedom in any way. But many years of trying to explain to my students why the fatalist is confused has convinced me that fatalist thinking runs deep. Some students get it; others never do. And it turns out that there are arguments for fatalism that are mistaken in ways that are much more subtle than the fatalist is usually given credit for. So the situation is this: Even though it’s a mistake, many people have the intuition that if it is "already true" what our future will be, then our future is not up to us; they think that truth alone -- regardless of determinism -- would rob us of free will. But if determinism is true, then there are detailed and specific truths about all our future choices and actions. So the intuition that determinism robs us of free will should not be trusted, for it might be a fatalist intuition in disguise.

Fourth Rule: Don't confuse 'that's really strange' with that's impossible.

Compare for a moment, a very different literature -- the literature about the possibility of time travel. Everyone in that literature understands that those who argue that time travel is impossible must show that the supposition that it is possible gives rise to actual contradictions. It is not enough to say -- indeed, we can all agree -- that a world where time travel takes place would be a most strange one.

In the free will literature, by contrast, one often hears remarks to the effect that a deterministic world is a very strange one, and we would have to believe very strange -- surprising! -- things if we combine a belief that determinism is true with a belief that we have free will. For instance, we would have to believe that if I were to raise my arm just now, then either the remote past or the laws would be different.

But sometimes the surprising is true. This is what the history of science teaches us, and if philosophy is to make progress it should sometimes be what philosophy teaches us.

Fifth Rule: Don't start with the hard cases -- the cases where it isn't clear what to say because we don't know enough to know what to say or because we are confused or conflicted about what to say. The free will/determinism problem is the problem of deciding whether the truth of determinism would have the consequence that the Free Will fact is never a fact, not even in the easiest cases,the ones about which everyone agrees.

Sixth Rule: Don't analyse. At least not at the start, not when you are defending the claim that we have free will (against someone who claims we never have it, or against someone who claims that having it is incompatible with determinism). If you proceed in this way, you are opening the door to the counterexample strategy. You are taking on a greater burden than you need to bear -- the burden of defending the claim that your analysis gives the "correct" verdict in the hard cases as well as the easy ones.

Compare: You don't need an analysis of 'chair' or 'game' to be entitled to say that there really are chairs and games, nor do you need an analysis to have the right to say that the existence of chairs and games is compatible with determinism. Nor are you thereby committed to the claim that chairs and games are primitive components of reality.

Concluding Remarks

 Back to the Free Will fact and the two objections that I mentioned at the beginning -- the fatalist's objection and the incompatibilist's objection.

These objections are treated very differently in the current literature. It is almost universally assumed that the fatalist conclusion is wrong and that the only philosophical problem is to show what is wrong with the fatalist's arguments. (Not all of them are as obviously fallacious as the Fatalist Fallacy.)

But no one thinks this way about the hard determinist or the incompatibilist.

I blame this on the fact that argument by poorly described thought experiments and appeals to intuition is now widespread and common.

It wasn't always so. Back in 1983, back in the days when the incompatibilist was accused of making the kinds of mistakes the fatalist makes -- of confusing causation with compulsion, descriptive with prescriptive laws, truth with necessity -- Peter van Inwagen wrote an entire book arguing that he, at least, was not guilty of any such simple mistakes. He claimed that there is an intuitively appealing and not obviously fallacious, argument for incompatibilism. He called it the Consequence argument.

I agree that this argument is not obviously fallacious. I also agree with van Inwagen that the disagreement between us is not a merely verbal dispute. He asserts what I deny -- that if determinism were true, then the Free Will fact would not be a fact. But, I claim, he is wrong. The Consequence argument fails. So far as this argument is concerned, it may be true that determinism is true and we have free will. And though I have devoted some time to this study, I know of no arguments that work.

So the state of play, at the present time, is that we have no reason to believe that the truth of determinism is incompatible with the Free Will fact. In the absence of other reasons -- in the absence of some other argument -- we are entitled to believe that the Free Will fact is a fact, and would be a fact even if determinism turned out to be true.

But I have digressed. I said that I would talk only about methodology, but I have ended up telling you the punchline of my book. I couldn't resist. But I still have free will. So I will exercise it by stopping.

_______________________________________________________________________________

This is from a talk presented at the Free Will conference at the Center for Cognition and Neuroethics in Flint, Michigan on Oct. 11-12, 2014.

Dennett Mele Templeton

Dan Dennett  reviews  Alfred Mele’s new book Free: Why Science Hasn't Disproved Free Will in October’s Prospect magazine.  

In the book Mele sets himself the task of explaining in terms accessible to everyone why recent highly publicized discoveries in neuroscience and psychology do not show, as some have claimed that "free will is an illusion". 

Dennett thinks Mele accomplishes his goal.  As Dennett notes, it is an important part of Mele's strategy to demonstrate that one need not take sides on the grand philosophical debate about free will to understand why the scientific "dis-proofs" are bunk. The grand philosophical debate is about whether free will is compatible with determinism, but Mele shows we can remain neutral about all that and still explain why nothing recently discovered in the lab should undermine the plain man's confidence that some of his choices are free.  

As Dennett says:

“…it may well be that his tactical neutrality on the issue of compatibilism will win him the support of the vast majority of philosophers who have thought hard about free will: we philosophers disagree vehemently about whether compatibilist free will is the only kind of free will worth wanting (as I, for one, have argued for many years), but we agree with Mele that the scientists have jumped to unwarranted conclusions, for the reasons he presents so calmly and clearly in this little book.”

We agree.  It’s a good book.  Indeed, it’s a model for the kind of writing philosophers should do more of if they hope to gain an audience outside of their cloistered specialties. 

But then Dennett says this:

“This review could similarly end on the mild, modest verdict that Mele has done his job and done it well. But there is a larger context worth considering. Suppose you were reviewing a scientific report that drew the conclusion that a diet without fat was in fact unhealthy, and that butter and cream and even bacon in moderation were good for you, and suppose further that the science was impeccable, carefully conducted and rigorously argued. Good news! Yes, but the author acknowledges in fine print that the research was financed by a million dollar grant from the Foundation for the Advancement of Bacon. We would be entitled—obliged—to keep that fact in the limelight. The science may be of the highest quality, honestly and sincerely reported, but do remember that the message delivered was the message hoped for by the funder. This is not reporting a finding contrary to the goals of the fact-seekers.

So it is important to note that Mele’s research, as he scrupulously announces, and not in fine print, is supported by the Templeton Foundation.”

This is, we think, is disgraceful. 

It is disgraceful because Dennett is coyly, with nodding winks and cunning smiles, inviting the reader to commit the ad hominem fallacy.

As first year critical reasoning students learn: you commit ad hominem when you criticize the arguer, not the argument.  It is a fallacious move because a logically valid argument is valid however evil or interested the arguer might be or who is paying him to make the argument.  

So take Dennett's fantasy story seriously.  What difference should it make that the nutrition study was funded by Big Bacon?  The right answer is none whatsoever.  What matters is the science that backs the study, not who backs the research. If indeed the science is "impeccable, carefully conducted and rigorously argued" then you are not "entitled", let alone "obliged" to keep its sponsorship “in the limelight".  You are in fact intellectually obliged to ignore that fact if you want to criticize the study (or review it for Prospect magazine) because the motives of the researcher or his employers are always beside the scientific point.

"Might not the evil Bacon People have encouraged the researcher to lie about his results?"  Maybe. But unless you have evidence that this has actually happened (so that the research is not impeccable) talking about the "goals of the fact-seekers" is slander, not science.

The Templeton folks are interested in advancing free markets and religion, not bacon and butter.  That makes them suspect in Dennett's eyes.  Fair enough, but how does this suspicion transfer to  Mele's philosophy? Is Dennett really accusing Mele of tailoring his philosophy to Templeton's ideology? 

Astonishingly, he is:

"Alfred Mele is in an unenviable position, and there is really nothing he can do about it. Was his decision to stay strictly neutral on the compatibilism issue a wise philosophical tactic, permitting him to tackle a more modest project, demonstrating the weakness of the scientific argument to date, or was it a case of simply postponing the more difficult issue..."

The suggestion here is clearly that Mele might really have refrained from discussing this issue, not because he thought it irrelevant to his project, but out of fear of offending his Templeton paymasters.

Framing it as a rhetorical question doesn't make this accusation any less slanderous. 

Dennett closes his review with an extended sneer:

“The Templeton Foundation insists that it is not anti-science, and demonstrates this with the bulk of its largesse, but it also has an invested interest in keeping science from subverting some of its ideological aspirations, and it just happens that Mele’s work fits handsomely with that goal. And that, as I persist in telling my friends in science whenever they raise the issue, is why I advise them not to get too close to Templeton.”

This is either silly or it is slanderous. If it is saying that scientific work is valueless if Templeton will fund it, it is silly.  If it is saying that Templeton funding inevitably corrupts those it funds, it is slander. 

Dennett owes Mele an apology.  

He owes his readers something else.  Ad hominem slurs are everywhere and they are everywhere poisonous to public discourse.  They are the weapon of choice in the culture wars that now seem to engulf every aspect of intellectual life.  This is something philosophers should deplore, not indulge.

As a public intellectual who is also a philosopher, Dennett owes it to us to set a better example.

Kadri Vihvelin

Terrance Tomkow 

_________________________________________________________________________

UPDATED: Dennett replies and the debate continues at Daily Nous.  Comments closed here.

A Note on Black Box Cases, Trumping, and Influence (and a warning about neuron diagrams)

On p. 162 of Causation: A User's Guide, Paul and Hall present a neuron diagram which they call a 'black-box case' and use it to argue that it refutes Lewis's Influence account and also teaches important lessons about causation. (The lessons: Don't jump to conclusions about causation until you know there are no further facts about internal causal structure. Don't assume that what is presented as a case of trumping is what it claims to be, rather than a case of overdetermination.)

I don't dispute their second claim; I think they are right to challenge the assumption that the "trumped" cause is not a cause. But they are wrong about the first. Their black box case does not refute the Influence account. If we think it does, it is because we have been misled by a neuron diagram.

Let's take a look.

The "black box" is represented by the neuron diagram they call 'Figure 30'.

Fig 30

Hall and Paul provide a brief description of the neurons C, D, and E and stipulate some facts about the firings of these neurons on a particular occasion, and also stipulate some counterfactuals about what would have happened if one or both of the neurons had not fired, or had fired on its own, or in a different color. They then say that these stipulated actual and counterfactual "outside" facts are consistent with at least three different internal causal structures and three different internal causal scenarios. They provide three neuron diagrams to depict these structures and scenarios.

Fig 31

Fig 32

  Fig 33

They tell us how to read the diagrams: Black and grey circles represent the strong and weak firing of neurons; empty circles represent non-firings. If a line ending with an arrow connects two circles, then the first neuron's firing (strong or weak) has the power to cause the second neuron's firing. If a line ending with a dot connects two circles, then the first neuron's firing has the power to prevent ("inhibit") or weaken the second neuron's firing. The checkerboard and striped neurons A and H of Figures 32 and 33 represent shunt neurons which have the job of "deciding" what to do when both neurons fire.

In Figures 31 and 32, the process initiated by C's firing goes through to completion, causing E's firing. But the process initiated by D's firing is cut off before it reaches E. In Figure 31, this happens because A's firing prevents G's firing. In Figure 32, this happens because A deflects the signal from neuron D to B, and sends only the signal from neuron C to E. In both cases, it seems intuitively clear that the causes of E's firing trace back to C's firing, and not to D's firing.

In Figure 33, by contrast, it is the process initiated by C's firing that doesn't go through to completion. In this diagram there are two pathways to E's firing, one along the upper channel, initiated by C's firing; and one along the lower channel initiated by D's firing. There are two causal gaps (empty circles) in the upper pathway: the failure of neurons A and F to fire. The lower pathway has no causal gaps. It seems intuitively clear that the causes of E's firing trace back to D's firing, and not to C's firing.

Hall and Paul's claim, then, is that the causal scenario depicted by Figure 30 underdetermines the causal facts. In two scenarios -- those depicted by Figs. 31 and 32 -- C's firing pre-empts D's firing as cause of E's firing. But in Figure 33, it is the other way around: D's firing pre-empts C's as the cause of E's firing. This refutes Lewis's Influence account because the Influence account must say that C's firing caused E's firing in all four scenarios. It must say this because the account says that an event E "is caused by every event with which it counterfactually covaries..to a sufficient degree." And in Figure 30, as well as Figs. 31, 32, and 33, E counterfactually covaries with C in exactly the way that Lewis deems sufficient for influence. Or so say Hall and Paul.

Are they right? Let's take a closer look.

Figure 30 is under-described, not just in terms of inner structure, but also in terms of "outside" laws and counterfactuals.

What actually happens is that C fires in black, D fires in grey (a shade of black), and E fires in black. We are told that if neither C nor D fire, E does not fire. We are told that if D fires, with or without C also firing, then E fires. But we aren't told whether E fires whenever C fires (with or without D). We are told that if C had fired in another color while D still fired grey, E would have fired in C's color, but that if D had fired in another color, while C still fired black, E would still have fired in black. But we aren't told whether it is always the case, when C and D fire in the same color, that E fires in the same color as C. From this limited information, we can draw only limited causal conclusions. We can conclude that E's firing is at least sometimes caused by D's firing, but we can't rule out the possiblity that it is also sometimes caused by C's firing. We can conclude that the color of E's firing is at least sometimes caused by the color of C's firing, but we can't rule out the possibility that it is sometimes (e.g. when both fire in the same color) caused by the color of D's firing. And because we can't rule out these causal possibilities, we cannot conclude that in the actual scenario (when C and D fired in different shades of the same color), C's firing caused either E's firing or the color of E's firing.

If Lewis is committed to false claims about this case (the Figure 30 case), on the basis of such incomplete information about counterfactuals, this would be very bad. However, I don't think he is committed to such claims. Let's take a closer look at his account.

The central idea behind the Influence account is that an event E causes (or is one of the causes of) another event F if the first event makes enough of a difference to the second event. (Since Lewis defines causation as the ancestral of this making-enough-of-a-difference relation, this condition is sufficient, but not necessary, for causation.) There are different ways in which an event might make enough of a difference to another event. One way -- the most common way -- is by counterfactual dependence: if it's true that if E hadn't happened, then F would also not have happened, then E made enough of a difference to F to count as a cause of F. But cases of causal preemption teach us that this isn't the only way in which one event might make enough of a difference to another event. In the classic late preemption case in which Suzy and Billy both throw rocks at a window, but Suzy's rock strikes first, shattering the window before Billy's rock arrives, the (non-fragile) breaking of the window doesn't depend on Suzy's throw. But the timing of the window-breaking depends on her throw; if her throw had not happened, the window would have been broken slightly later, by Billy's rock. And the manner of the window-breaking depends on her throw; if her throw had happened in any of a number of different ways (different spin, different aim point, different velocity, with a rock of greater mass), the window-breaking would have happened in one of a number of different ways.

At this point you might object on the grounds that Billy's rock throw also makes a difference to the timing and manner of the window-breaking. If Billy's rock throw had happened early enough -- earlier than Suzy's throw -- the window would have been broken earlier, by Billy's rock. And if Billy's rock throw had happened in a suitably different manner (if he had thrown harder, or faster), his rock would have reached the window before Suzy's rock, and the breaking would have happened differently. Lewis grants this, but, he insists, if Suzy's rock throw preempted Billy's as cause of the window-breaking, then it must be the case that her throw made more of a difference to the breaking than his did. The window-breaking is more counterfactually sensitive to Suzy's throw than it is to Billy's. It takes only small differences in the timing or manner of Suzy's throw to make a difference to the window-breaking; it takes greater differences in the timing or manner of Billy's throw to make similar differences to the breaking. He contrasts this with a case in which both rocks arrive at exactly the same time, and strike the window in a way such that neither makes more of a difference to the manner of the breaking. In this case, the two are equals with respect to Influence, and we should count each of the rock throws as a cause of the window-breaking. Intuitively this seems right; how exactly this can be cashed out in every case of preemption and overdetermination is more dubious. But set aside these worries and notice only this central and crucial feature of Lewis's account: to conclude that one event caused another (in cases where we don't have information about whether there is a causal process connecting the two events), we must know not only that the first event made a difference to the second event; we must also know that the first event made more of a difference than any other event that was a potential cause of the second event. In other words, the Influence account says that Influence is both a "graded" or comparative relation (enough of a difference, where this is a matter of balancing and comparing different difference-making respects) and also a contextually dependent relation (since a very slight difference may still count as enough of a difference in cases where there are two potential causes of a single effect).

With this in mind, let's see what Lewis would say about the Black Box case of Figure 30.

The first thing to note is that the stipulated counterfactuals about Figure 30 are incomplete, so far as the Influence relation is concerned. They tell us that C's firing makes a how-how difference to E's firing (if C had fired in a different color, E would have fired in a different color) and they tell us that D's firing makes a when-when difference to E's firing (if D had fired earlier or later, E would have fired earlier or later. And they tell us that C's firing doesn't make a whether-whether difference to E's firing (If C had not fired, E would still have fired, thanks to D.) But we aren't told about other ways of making a difference. For instance, we are not told whether it is also true that if C had fired earlier or later, then E would have fired earlier or later. So we don't know whether C's firing makes a when--when difference to E's firing. And we aren't told what would have happened if D had not fired. So we don't know if D's firing makes a whether--whether difference to E's firing.

Given that all the relevant counterfactual facts are not known, Lewis is not committed to any causal judgments about Figure 30. He should say that, so far as we know, it might be that C's firing makes more of a difference than D's firing, or that D's firing makes more of a difference, or that the two events are equals with respect to the difference they make. Until we are in possession of further counterfactual facts about the case, we should reserve judgment about causation.

The stipulated description of Figure 33 provides us with more details.

We are now told that that if C fires, with or without D also firing, then E fires. This means that C's firing makes a when-when difference to E's firing and D's firing makes no whether-whether difference to E's firing. So we now know that C's firing and D's firing are equals with respect to when-when influence (both have it) and whether-whether influence (neither has it) with respect to E's firing. Since C's firing makes a how-how difference to E's firing, and D's firing does not, it follows that C's firing makes more of a difference to E's firing than does D's firing. The case now looks like a neuron version of Schaffer's Major-Sergeant trumping case. 

And it looks like Hall and Paul are right to conclude that Lewis must say what he says about that case: that E's firing is caused by the event with greater Influence -- C's firing (the Major's command) -- and not by the event with lesser Influence -- D's firing (the Sergeant's command).

Hall and Paul are partly right. Lewis would say that E's firing is caused by C's firing. But they are partly wrong. Lewis would not deny that E's firing is (also) caused by D's firing. Recall that Lewis defines causation as the ancestral of Influence. Influence is not transitive. It follows that one event (e.g. D's firing) may cause another event (e.g. E's firing) even though the first event doesn't stand in the Influence relation to the second, provided that the first event is connected to the second event by a sequence of events, each of which stands in the Influence relation to the subsequent one. And this is true of D's firing and E's firing. D's firing Influenced (and thus caused) B's firing, B's firing Influenced (and thus caused) G's firing, G's firing Influenced (and thus caused) E's firing. 

Is this consistent with what Lewis says about trumping? Well, Lewis does say, about the Major/Sargeant case, that we are not entitled to assume that the case works by 'cutting',  and so we are not entitled to assume that there is a causal chain of events between the Major's order and the soldiers' advance. That's why he accepted the trumping case as a counterexample to his earlier, simpler analysis of causation, and this is why his new Influence account allows us to say, as the old account did not, that the Major's command directly caused the soldiers' advance. The Major's command directly caused the soldiers' advance because his command had greater Influence on their advance than did the Sergeant's command. But since influence is only sufficient and not necessary for causation saying that the Major's order caused the advance is consistent with saying that the advance was also caused (by way of a causal chain of intermediate events) by the Sergeant's command. In other words, Lewis can say that what looks, at first glance, like a case of trumping might, on further investigation, turn out to be a case where both potential causes are actual causes of the effect. 

At this point you might object: This is all well and good, but it doesn't rescue Lewis, Even if he can say that D's firing is a cause, by transitivity, of E's firing, his account commits him to the claim that C's firing is also a cause of E's firing. And that's wrong. In Figure 33, the causal pathway to E's firing goes by way of D's firing, and not by way of C's firing. This shows that Influence, even when understood in the more complex way that I've explained, does not suffice for causation. Therefore Hall and Paul are right after all. The Black Box case refutes the Influence account.

But I respond thus: Yes, Lewis is committed to the claim that in the Figure 33 scenario, C's firing is one of the causes of E's firing. But a closer look at the stipulated facts of the case shows that this is the right result. The shunt neuron, H, "decides" whether to direct neuron signals along the upper or lower pathway. It "decides" this on the basis of incoming information from neurons D and C. If neither C nor D fire, H "does nothing". If C and D fire in different colors, H fires one way (let's call it "down"), inhibiting D's signal and allowing C's signal to go through along the upper pathway. If C and D fire in the same color, H fires another way (call it "up"), inhibiting C's signal and letting D's signal go through along the lower pathway. This is the actual case, and since the neuron diagram depicts all the neurons in the lower pathway as firing, and depicts two neurons in the upper pathway not firing, we conclude that E's firing is caused only by D's firing and not by C's firing. But this is a mistake that comes from confusing what we say about object causation with event causation.

Compare: Sylvie's throw was aimed away from the window, and would have missed, while Bruno's throw was aimed directly at the window. But the two rocks collided in mid-air, and the result of the collision was that Sylvie's rock struck and broke the window, while Bruno's missed altogether. In this case, it was only Sylvie's rock, and not Bruno's rock, that caused the window-breaking. (We might say that his rock caused her rock to break the window, and we might even say that his rock caused the window-breaking, by causing her rock to break it. But we wouldn't say that his rock broke the window, or that his rock caused the window breaking, full stop.) But Bruno's throw - the event - was among the causes of the breaking. It (jointly with Sylvie's throw) caused the collision, which caused the breaking. 

The analogy isn't perfect, but if we compare neuron signals to rocks, we can compare Sylvie's rock to the signal from neuron D and Bruno's rock to the signal from neuron C. The firing of the shunt neuron, H, is like the collision of the rocks. The upshot of H's firing, in the Figure 33 case, is that the signal from neuron C is stopped while the signal from neuron D makes it all the way to neuron E. So if we think in terms of object causation, we conclude that E's firing was caused by D (the neuron, by way of the signal sent by the neuron), and not by C. But if we stay focused on event causation, we'll see that C's firing -- the event -- was among the causes of E's firing. It (jointly with D's firing) caused H's firing, which caused E's firing.

Therefore Hall and Paul are wrong. Lewis's Influence account delivers the correct verdict about this complex case. Contrary to what I said earlier, our initial classification of Figure 33 as a case of causal pre-emption is mistaken. C's firing and D's firing are joint causes of an intermediate event, H's firing, and this intermediate event causes E's firing. If some alleged cases of trumping turn out to have this kind of causal structure, then it is a mistake to classify them as trumping (since trumping is a species of preemption). This is an important point. But Hall and Paul are mistaken, for the reasons I have given, to think that this point counts against the Influence account.

Why did Hall and Paul think otherwise? Why did they think that Figure 33 is a kind of causal pre-emption scenario, as opposed to being a case where C's firing and D's firing are both causes of E's firing?

Well, one of the reasons is the one I've already explained -- the tendency to slide from talk of what objects (rocks, bullets, neuron signals) cause to talk of what events cause. But there is another reason, having to do with the limitations of neuron diagrams.

The way that neuron diagrams are presented encourages us to think that they are highly simplified but nevertheless unambiguous representations of the causal facts. But this isn't the case because the diagrams are set up to represent two different kinds of causal information: information about causal laws and information about causation in a particular case.

The circles (filled and blank) do double duty; they represent objects (neurons) and also occurrences and non-occurrences of event-types (neuron firings). The lines with arrows and dots connecting the circles also do double duty; they represent nomologically possible sequences ("pathways") of occurrences (filled circles) or non-occurrences (empty circles) of events and they also represent actual sequences of occurrences and non-occurrences of events.

Our instructions for how to read the diagrams are incomplete, but we are not warned of this. For instance, we are not told how to read the following simple neuron diagram: two filled circles, A and B, are connected by lines with arrows to a third filled circle, C.

Is this a case where A and B are joint causes of C? Or is it a case where A and B are overdetermining causes of C? Or might it even be a case where one of the two is the actual cause and the other is the merely potential but pre-empted cause? The instructions for reading the diagrams do not tell us.

It follows, from this simple example, that neuron diagrams, by their very nature, cannot be relied upon to depict the causal facts of a particular case.

You might think that they can at least be relied upon to tell us what the causal laws are. But this isn't true either. In order to know whether A-like events are joint causes, with B-like events, of C-like events, or whether A-like events are capable of causing C-like events without the help of B-like events, we need to know more than what the diagram can depict.

It follows that we should not rely on a neuron diagram for verdicts or intuitions about what either the particular or general causal facts are. Yet this is precisely what we did when we first looked at Figures 31, 32, and 33.

You might protest, at this point, that neuron diagrams can still be useful. Even if they don't provide an unambiguous depiction of all the causal facts, they depict some of them, and so long as we are careful to supplement our interpretation of the diagrams with the stipulated description of a particular case, we will not be led astray.

But we were led astray, when interpreting Figure 33. And I speak from bitter personal experience here. It took me a long time to figure out the true causal facts about Figure 33.

The problem, as I already noted, is that it is easy to speak the language of object causation, and then switch from this to the language of event causation. Sometimes this is harmless, but not always.

Recall that in describing Figures 31 and 32 we followed Hall and Paul in speaking of a signal "travelling" and the neuron A "sending a signal along a path". When we speak this way, we are thinking of neuron signals as persisting objects, like rocks or baseballs. And this encourages us to think that if the signal sent by one neuron (e.g. D, in Figure 32; e.g. C in Figure 33) doesn't make it all the way down its "pathway" to another neuron (e.g. E, in Figure 32 or 33), then that neuron's firing did not cause the firing of the second neuron. (Compare: Billy's rock never made it to the window because Suzy's rock got there first, so his rock throw didn't cause the breaking of the window.)

Thinking this way doesn't get us into trouble with Figure 32. In Figure 32, the causes of E's firing trace back, via A's firing, to C's firing and not to D's firing. But in Figure 33, thinking in terms of causation by a persisting object does get us into trouble. We can agree that it was the signal sent by D, and not the signal sent by C, that caused E's firing. But in this case, unlike the case when only one neuron fires, both neuron firings were causes of H's firing, and thus, by transitivity, both were causes of E's firing.