Determinism: an idea that just won’t fly
|October 12, 2012||Posted by vjtorley under Intelligent Design|
I have just been listening to a talk on the subject of free will, by the British philosopher Jonathan M. S. Pearce, who contributes to the blog, Debunking Christianity. The talk was given to a meeting of Portsmouth Skeptics in a Pub on 14th June 2012, which was attended by about 50 people. A podcast of the talk is available online here.
In this post, I’d like to focus on what I take to be Jonathan’s key argument against free will. After making this argument, he then goes on to critique dualism and put forward scientific arguments against free will. I have already addressed these criticisms in previous posts, so I won’t be rehashing them here. Instead, I’ll just list the papers, for any readers who may be interested.
Useful background reading on free will
Regular readers of this Web site will know that I have written several posts on the subject of free will, in which I attempted a defense of free will from a dualist perspective, according to which persons (not souls) are capable of holistically interacting with their brains, thereby enabling them to move their bodies. Readers who would like a good summary of why I find this kind of dualism persuasive, and why I find materialism untenable, might find this account of mine beneficial:
The Stumbling Block For A Materialist Account Of Mind: Intentionality, which is section D(vii) of my online book, Embryo and Einstein: Why They’re Equal. For references to articles by other philosophers against materialism, please see section D(viii): Why Intentionality Cannot Be Explained In Purely Physical Terms: A Short Bibliography.
Here’s an article on why I consider free will and physical determinism to be incompatible:
Battle of the two Elizabeths: are free will and physical determinism compatible?
Finally, here’s an article which rebuts the major scientific arguments against free will:
Is free will dead?
What assumptions are required to defend libertarian free will?
Jonathan M. S. Pearce defines libertarian free will in terms of the Principle of Alternative Possibilities: if you belierve that there are some choices you have made for which you could have done otherwise, then you believe in libertarian free will.
In my post, Why I think the interaction problem is real, I argued that in order to defend libertarian free will, we need to affirm at least two things:
(i) people can holistically influence their brains; and
(ii) top-down (macro–>micro) causation is real and fundamental.
Additionally, if we find the philosophical arguments against materialism persuasive (see here for a detailed statement of what I consider to be the best of these arguments), then we will also need to acknowledge that:
(iii) some human actions (namely, thoughts and choices) are non-bodily actions, and that by performing these actions, human beings are capable of influencing events occurring in the cells of their bodies.
However, it seems conceivable to me that a materialist who was prepared to accept the notion of holistic top-down causation, while rejecting the view that thoughts and choices are non-bodily actions which holistically influence our brains, could still consistently believe in libertarian free will. So believing in (i) and (ii) but not (iii) is also consistent, for someone who accepts libertarian free will.
While listening to Jonathan M. S. Pearce’s argument, I noticed that he used a lot of terms without bothering to define them. If he can’t define the idea of determinism in a rigorous manner, then it makes no sense to say that it is true, and to use that as an argument against libertarian free will. I found myself asking the following questions that I wanted to put to Jonathan:
What’s the universe?
Jonathan humorously began his talk by thanking the universe for having brought everyone in the audience together in this pub. But what is the universe, and by “universe,” does Jonathan mean the entire multiverse or the particular bubble of the multiverse that we happen to live in, or the observable portion of that particular bubble? Some philosophers have seriously argued that the very concept of “the universe” (or if you prefer, the multiverse) is incoherent, and that it cannot be meaningfully defined by us, as it is not an individual: there is no such “thing” as “the universe.” (On the other hand, a cosmologist told me once that cosmology is the scientific attempt to treat the universe as if it were a single object.) Since the universe figures in the definition of determinism, it follows that if the universe cannot be satisfactorily defined, then neither can determinism.
What’s a cause?
This term is vitally important, in the context of any argument for determinism. In particular, is it true by definition that every cause determines its effect? If so, why? In everyday life, we typically find that an effect X is the product of several contributing causes (A, B, C, …), each of which is insufficient to determine the effect. So it seems that the idea of a non-determining cause is a perfectly coherent one. You could try to get round that problem by saying that you’ll define the whole set of contributing causes as the cause of X. But then what you’re saying is that the notion of the totality of causes is logically and/or epistemologically prior to the concept of a partial or contributing cause. This, it seems to me, is putting the cart before the horse.
What’s a causal chain?
Jonathan appealed to this idea several times, in his talk on free will. For instance, he talked about causal chains going all the way back to the Big Bang. Now, I think we can all imagine a causal chain of the form A->B->C->D->… However, this is an atypical case: it’s a purely linear chain, and every link has one and only one immediate predecessor. Typically an event has multiple causes, and a contributing cause for one event is typically also a contributing cause for other events as well. That means that our chain has turned into a complex, tangled grapevine. “No problem,” you might say. “In the end, it all goes back to the Big Bang, doesn’t it?” Well, it might in this universe, but what about in the multiverse as a whole? There may be no single point from which all the various chains converging on a cause originate. If that’s the case, what becomes of the notion of determinism?
Here’s another problem. Chains often contain loops. Is it part of the definition of determinism that there are no loops, in which a present effect has causes which lie in the future as well as the past? If there is even one such loop in the history of the universe, then Jonathan’s notion of determinism no longer holds up. My question is: how do we know that there are no such loops? Is there any law of physics which precludes them, for instance? If so, which one?
What’s a reason? Is a reason the same as a cause?
Throughout his talk, Jonathan argued that every effect needs to have a reason or cause, otherwise it’s random and not free. In the question session afterwards, Jonathan distinguished between two senses of “reason”: a “why” reason (or a purpose or goal), and a “prior causal” reason (or a causal antecedent). He even chided the philosopher C. S. Lewis for failing to make this distinction. (I would agree that that’s a fair criticism of what Lewis said in his famous debate with Elizabeth Anscombe at the Oxford Socratic Club on February 2, 1948, but by the time he wrote “Miracles,” Lewis had had time to formulate a more nuanced argument. Gavin Ortlund has an interesting post on the aftermath of the debate, here. In fact, the philosopher Victor Reppert has recently written a book on Lewis’ argument, and why he considers it sound. But I digress.)
Repeatedly, during his talk, Jonathan argued that our choices must have a reason or cause, otherwise they’re just random. But it seems he is equivocating here. What if our choices have a “why” reason, without having a “prior causal” reason? That seems a perfectly coherent possibility to me. A choice with a “why” reason would not be a random one: it would have a clearly defined goal or purpose.
Jonathan might argue against this possibility by appealing to the principle that every event has a cause. A choice is an event, therefore a choice has a cause. Right? Not so fast. The principle that every event has a cause is arguably true from a scientific standpoint, if one is talking about micro-level events at some point or very small region of space and time. But a choice isn’t an event like that, and you can’t argue that it can be decomposed into a set of events like that, without assuming the truth of reductionism – which is question-begging.
Jonathan might also object: “If you (or your soul) make a choice NOW in order to attain some goal, but nothing causes you to make that choice NOW, then I would argue that your choice is random. Why did you make that choice when you did? Surely that’s a valid question.” The objection assumes that we make choices in time, which is a bit odd, given Jonathan’s preference for a block-theory of time, but we’ll let that pass. The point I want to make is that even if there is some causally determining reason which explains why I made the choice NOW (e.g. someone suddenly walked up to me, held a gun to my head, and said: “Choose A or B!”), that cause wouldn’t need to determine my actual choice. (For instance, the man holding the gun to my head might be supremely indifferent to which option I choose: perhaps he just wants me to decide, because he can’t stand the sight of me dithering.) So my argument that our choices have a “why” reason, without having a causally determining reason, emerges unscathed from this criticism.
What’s a natural law, or law of Nature?
If causes determine their effects, then presumably they do so by virtue of acting in accordance with the laws of Nature. But what is a law of Nature, and what makes it a law which events have to conform to, rather than a mere regularity which events happen to conform to? After all, a general statement which holds true at all times and places might just be true by accident. To use an oft-cited example, it’s probably true that every lump of gold in the history of the universe has a volume of less than a cubic kilometer, but that doesn’t make it a law. Substitute “uranium-235” for “gold,” on the other hand, and I think most of us can see at once that the situation described is impossible, because uranium-235 has a critical mass. But what makes a law impossible to break?
One common answer is to appeal to Noether’s theorem to explain the invariance of laws over space and time. The gist of the theorem is that if a physical system has a corresponding Lagrangian function describing its dynamics, and if this function exhibits a certain kind of symmetry, then it follows automatically that the laws describing that physical system will be invariant across space and time. What this answer is really saying, then, is that the laws of Nature are a product of the mathematics describing the universe itself, at its most fundamental level. Asking why laws of Nature hold is like asking why a square has four sides: it has to, or it wouldn’t be a square.
I don’t buy that, and here’s why. A geometrical object has no contingent properties. Everything we can say about a square follows from its definition. If we look at the universe, on the other hand, it doesn’t appear to be like that. For one thing, its initial conditions are hardly part of its definition: they seem to rather be properties imposed on it. So we’re not living inside some Platonic realm of forms, whose every feature is explicable in terms of their underlying geometry. And if someone were to assert that we are, I’d retort that extraordinary claims demand extraordinary proofs. A few experiments showing that children with this or that gene or environment, tend to turn out in a certain way 20 years down the track (to cite one of Jonathan’s examples in his talk) falls a long way short of proof. All it establishes is that our free will is to some degree constrained – and who would deny that?
The universe, then, has at least some contingent properties. If we are going to speak of the universe as an individual (let’s call it “Alf”), then Alf’s laws are its form, which makes it the kind of individual it is. (I’m using form here to mean “essence”, or more precisely an Aristotelian substantial form.) If Alf had different laws, then it would be a different kind of universe. OK, fine. But if that’s the case, then we are supposing that this universe (Alf) might have been a different kind of universe. Someone or something made Alf the kind of thing it is, thereby endowing it with its essential properties. So instead of a self-sufficient Platonic geometrical form, what we have is an individual that was endowed by someone or something with the nature it possesses. On this picture, the laws of Nature are no longer merely descriptions of its underlying geometry; they are prescriptions (or rules) imposed on an underlying subject (Alf) which could have been made differently. But I would argue that the very concept of a mind-independent prescription makes no sense. It is incoherent. This is an important, because Jonathan wants to argue that if determinism is true, then there cannot be a God who rewards or punishes us for our actions. But if Jonathan cannot define the cosmos without appealing to terms which require us to invoke a God to make sense of them, then his project is doomed from the start. So Jonathan has to offer us an account of laws which explains why they “stick,” without invoking the concept of a rule or prescription – or otherwise he will be implicitly appealing to a Mind behind the cosmos, which he doesn’t want to do.
What’s a path?
In his talk, Jonathan invoked the notion of a path. If the Principle of Alternative Possibilities is true and we have libertarian free will, then we sometimes have two or more paths before us. If determinism is true, then we only have one path. This is a nice metaphor, but it lacks definitional rigor. What exactly is a path? If you want to define it in terms of possibility, then what does “possible” mean? It’s quite a tricky term to define.
One explanation Jonathan gave to illustrate the concept of determinism was to appeal to the metaphor of a set of falling dominoes. However, it seems to me that this is nothing more than a handy pictorial image: it might serve as an aid to thought, but never as a substitute for it. We still want to know: what does the term “determinism” mean?
I was very surprised that when Jonathan finally attempted to define determinism, he appealed to the notion of Laplace’s demon: a hypothetical being who knows everything about the laws of Nature and the positions and movements of the particles in the universe, and who, using this information, is able to predict with perfect accuracy, every future state of the cosmos. (I’ll leave the quantum mechanical objections aside here, as some interpretations of quantum mechanics are deterministic.) However, many philosophers would object to Jonathan’s characterization of determinism, arguing that it confuses the notion of determinism with that of predictability: the universe, they contend, might still be determined, even it its behavior is impossible in principle to predict. Perhaps Jonathan might reply that this would still leave the concept of “determinism” undefined, and that determinism can only be made sense of by appealing to the notion of “in principle” predictability. On this point, I think he’s probably correct.
I would argue, though, that Jonathan’s definition founders on the question of whether the existence of Laplace’s demon is possible, given the laws of the cosmos. If he answers “No,” then he is conceding that his definition of determinism presupposes the notion of an entity whose existence is precluded by the very laws of the universe whose infallible efficacy he is trying to explain. In other words, hes sawing off the branch he’s sitting on. But if he answers “Yes,” then he has swapped one God-figure (a retributive judge of every human being), for another God-figure (an omniscient being who knows everything you’ll do, but of course won’t punish you for it, because you couldn’t help it). Now, Jonathan might prefer God-2 (Laplace’s demon) to God-1: at least he won’t have to worry about Hell, although he’ll have to give up on the idea of Heaven. But it does seem that if you have to bring in a God-figure (whether actual or merely possible hardly matters here) to explain a theory which is meant to dispense with the very idea of God, then you haven’t gained anything, in terms of explanatory simplicity. You still have to invoke at least a notional God, to make sense of your cosmos. And I would ask: what’s the point of that?
I conclude that the concept of determinism has yet to be given an adequately rigorous formulation. Appealing to the notion of determinism in order to discredit the idea of libertarian free will is therefore a misguided enterprise, doomed from the start.
A short comment on Jonathan’s argument
So, what was the argument put forward by Jonathan for determinism? In essence, it was that a choice is an event, and that if an event is not caused, it is random. But a random event is not a choice, so our choices must be caused. Moreover, our choices must be caused in a deterministic fashion, otherwise there would be no reason why I chose (say) A rather than B, which would again make my choice of A rather than B a random one. But a choice which is caused in a deterministic fashion isn’t a free choice in the libtertarian sense, so by a reductio ad absurdum, we are forced to conclude that libertarian free will is impossible.
Now, it seems to me that Jonathan is implicitly appealing to a rationality norm here: that for any state of affairs where there are two possibilities, the question, “Why A rather than B?” is always a legitimate one to pose. And when Jonathan asks “Why?” he isn’t looking for a reason. He’s looking for a cause that would answer the question.
But if Jonathan thinks that this question deserves an answer, then he is assuming the very thing that he is trying to prove: namely, that for every option selected, there is a determining cause. This is what is called begging the question.
If someone asks me why I chose A rather than B, and if A and B are both ends rather than means, then it is surely enough to answer that I chose A because I liked A rather than B – which is quite different from saying that I chose A because my desire for A was stronger than my desire for B. That kind of answer is a mechanistic one. But choices are not mechanistic things.