Tuesday, February 13, 2007

Determinism is Dead

Stephen Barr is probably my favorite science writer these days: he is both an authority in theoretical particle physics at the Bartol Research Institute at the University of Delaware, and an orthodox Roman Catholic who believes, as do I, that science and religion are not only compatible in the sense that they do not contradict each other, but they are, in the words of John Paul the Great, the two wings of human experience that together lift us to knowledge of the Good and the True. So I was particularly excited when the March number of First Things appeared in my mailbox today sporting a tidy little essay by Professor Barr entitled “Faith and Quantum Theory.”

The article presents an argument that I find quite congenial, having made a version of it myself over ten years ago (see Robert Brandon and Scott Carson, “The Indeterministic Character of Evolutionary Theory: No ‘No Hidden Variables’ Proof, But No Room for Determinism Either,” in Philosophy of Science 63 [1996], pp. 315-337. The article is available online if you have access to JSTOR. Otherwise, you’ll just have to wait until the movie comes out). The upshot of both his and my articles: Determinism is dead. Not just dead as in, we can’t figure out how to make it work. Dead as in, it’s metaphysically not possible unless you’re willing to commit yourself to a metaphysics that is, in a word, insane.

Sometimes, when I teach the history of Presocratic philosophy, I will have students who ask questions about the metaphysical schemes of the Pythagoreans, questions about the viability of such schemes and about the very motivation behind seeing the world in the way that they did. If you’re not familiar with the Pythagoreans or their schemes, one aspect of their thought that has made them rather notorious is their proposal that the observable world is, in some sense, reducible to numbers or, as Philolaus proposed, known through numbers. To understand this proposal fully would require a rather detailed knowledge of ancient metaphysics and philosophy of mathematics, so I won’t go into more detail here. Suffice it to say that, when I get these questions from my students, I’m often tempted to point out that it is not all that different from what contemporary physicists are prone to do. We, too, represent the world numerically, particularly in the form of scientific equations but also in the form of predictions and explanations that are expressed in terms of probabilities.

Now, if you are a determinist, you view these probabilities as epistemic in nature. That is, if someone tells you that there is a 30 percent chance of rain tomorrow, if you are a determinist you think that what is meant by that is that, if only we knew everything there is to know about a particular weather system, down to the disposition of every last material particle, then we could say with 100 percent certainty whether it will rain tomorrow or not. But we cannot have that kind of complete knowledge of such a vast and complex physical system as the entire atmosphere of the earth, so our prediction reflects a certain amount of uncertainty on our part that is due to our lack of complete information.

There is another way to interpret probabilities, however, and it is much more congenial to both quantum mechanics and evolutionary theory. We may call this the metaphysical interpretation, because it posits that probabilities reflect, not limitations in our own knowledge of the physical universe, but the stochastic properties of a non-deterministic universe. That is, on the metaphysical interpretation of probabilities, we say that there is a certain chance that something will happen not because we do not know for sure what all of the variable are that will lead to one outcome rather than another, but because it is genuinely undetermined, at the time of our prediction, which outcome is going to take place.

Although he does not say much about this in his article, Professor Barr notes that this view of probability is congenial not only for quantum theory, but also for those who endorse the idea that the human will is free. As I mentioned in one of my earlier posts in this series, if the universe is a purely deterministic place, where materialism is the only correct metaphysics, then our wills cannot be free. So if you happen to believe that your will is free, it seems that you have to abandon either materialism or determinism. Some will want to abandon both, of course: the Christian must, in my view. But even if you are wedded to your materialism it might be time to dump that dinosaur, determinism.

We can’t, of course, take it for granted that our wills are free. Part of the point of these explorations of mine is to enquire into whether it is, in fact, possible to make any sense out of human freedom. It is worth emphasizing, however, that unless global determinism is false, we cannot be free. That is a controversial view (it was denied, for example, by Hume, and continues to be denied by the more dogmatic compatibilists), but I will not argue for it, since I doubt that many of my readers will find it all that problematic. In these matters, much depends upon one’s starting points.


John Farrell said...

"Stephen Barr is probably my favorite science writer these days..."

Mine too. It helps also that he isn't one of the seemingly ubiquitous 'senior fellows' of the Discovery Institute.'


BTW--where was that great quote from JPii from? Fides et Ratio?

Scott Carson said...

Fides et Ratio was what I had in mind, but I was really just paraphrasing it from my (rather weak) memory--it said something along those lines but I'm not certain I got the words exactly right.

Rick said...

Should we distinguish determinism from strict determinism? In a certain sense, no human person is totally free because of the multitude of factors (genetics, culture, education, family, previous choices, etc.) that influence our choices, such determining factors enter into all our choices. This certainly does not disprove free will. However, strict determinism seems to argue that all choices are in some way determined. But, is this view contrary to our human experience and knowledge?

Doesn't one experience "freedom" in choices? Maybe this example will help. For instance, an alcoholic man can choose to drink (x) or not drink (~x). Even if we grant a genetic component to the man's alcoholism, at some point he had to make the choice to drink habitually to allow it to become an "ism". Conversely, say after getting drunk every day for 40 years, he chooses to stop drinking because he realizes all the damage it has caused and then seeks all the means to get help and make amends. It would be hard to say both his alcoholism and his sobriety were both determined. He must make a free "choice" everyday to drink or not to drink. Granted, that choice is limited by his past experiences which in some sense make it hard to choose sobriety, but all the more it shows the freedom in making the choice to remain sober.

We often choose between contradictory or contrary things based on reasoning to the best possibility. I think we could argue that such choices are not determined, to choose sobriety after drinking for a long time is a choice based on reason among possibilities. As long as one can choose among possibilities which are contradictory, it would be hard to hold that x and ~x are both determined. The more he chooses not to drink the freer he becomes in terms of his choice of sobriety. Every day, this involves a rational free choice, the more he chooses sobriety the freer his necessity to drink becomes. I think such experiences (other forms of addiction) occur to many folks that give ample proof of freedom and thus disprove strict determinism.

Scott Carson said...


The case against free will requires materialism and determinsim. If you accept both of these (one a metaphysical view, the other a methodological one), then all choices, whether they appear to us to be freely made or not, are determined by purely physical constraints that are not under our control. In your example, the alcoholic who chooses not to drink after 40 years may believe his choice to have been free, indeed, it may have been a very difficult choice for him to make and he may feel that he is actually "going against" something internal to him driving him towards drink (i.e., the addiction), and this all contributes to his feeling that the choice was freely made and fully up to him, but the person who denies free will can simply point out that none of this entails that he could have acted other than he did, which is the key test for freedom. If it is not possible to act other than he did, then he was not free.

The upshot of this is that the mere feeling that we could have acted other than we did is not a sufficient proof of the metaphysical fact that we could have acted other than we did, so it does not, all by itself, establish freedom of the will.

The difficulty is that, when we choose between (x) and (~x), we only ever choose one of them at a time, and so there is no evidence at all, empirically, that we could have chosen the other if we had wanted to, nor is there any evidence that what we wanted to choose was ever up to us in the first place.

The only way to escape from this is to deny either materialism or determinism or both outright--it can't go the other way (disproving determinism by examining choices); I advocate rejection of both globally, though I admit that local versions of each can be adopted for the purpose of scientific inquiry. That is, the biologist or the physicist can adopt local materialism and determinism merely for the purposes of playing the language games that are biology and physics without endorsing global versions of either.

Rick said...


Thank you for the response. I think this is something that I will have to process for a while to digest it.

Based on what you said, we would simultaneously have to disprove materialism and determinism. Based on Dr. Barr's book, I think it materialism claims are refutable, one being the proposition "everything is made of matter" cannot be proven empirically, proven to be true or false, or to be made of matter.

But, determinism seems harder. Would we have to show our biology has a metaphysical link, a metaphysical biology? Here, could we say that our inclinations for the good are more than biology, more than determined. MacIntyre argues that our early development has prelinguistic capacities which are in some way determined (he calls this our animal nature-I am not sure I like the term), we act for proximate goods to meet our needs. As we learn to conceive pf the good, we can then make choices based on our knowledge of the good. First, pre-linguistically, we experience the good, when the linguistic capacities develop we "know" good is to be done and evil must be avoided. If we can then identify types of goods based on our powers of knowing, we can then see there is are goods for which we can act choose to act that are beyond natural inclinations. I have to think about this more.

Though, I see what you are saying. If freedom is merely the choice between contraries, Pinckaers calls this the freedom of indifference, which seems to be inherently materialistic, here freedom equates to nothing but natural inclinations which is really determinism and thus not freedom at all.

I will be very interested to follow your posts on the subject. Thank You!

Scott Carson said...


I agree with much of what you have to say. Materialism is clearly an a priori assumption, not something that any scientist has ever argued for, and of course any empirical (that is, scientific) argument for it would beg the question, since empiricism presupposes materialism.

As for determinism, I would recommend looking into the work of John Bell. A good place to start would be his Speakable and Unspeakable in Quantum Mechanics (Cambridge University Press, 1987). His work showed that we must abandon one of three things: either (a) quantum mechanics itself; (b) locality; or (c) determinism. Most physicists are unwilling to give up either (a) or (b), so (c) must go. And if you look at the article I cite in the main post, Robert Brandon and I present an argument to the effect that the same conclusion is warranted (though not provable) in biology as well.

Brandon said...

So you're that Scott Carson; I've read the article, and have it in a file somewhere, but didn't ever connect it to you.

Scott Carson said...

Uh oh...so my cover is blown, eh?