Tuesday, September 20, 2005

A brief note on "free will"

Every conceivable behavior is either deterministic, or random, or some combination of the two. Neither determinism nor randomness can possibly qualify as free will --- intuitively, neither a clock's gears nor a pair of dice possess free will --- and therefore the very concept of free will is philosophically incoherent.

To elaborate slightly, behavior either follows a set of predictable rules, or it does not. If behavior follows a set of predictable rules, then those rules constitute a deterministic algorithm, which clearly lacks free will. If behavior does not follow a set of predictable rules, then it is a random process, which clearly also lacks free will. In practice, most nontrivial behaviors must be modeled by a combination of deterministic and random elements, but combining the two into a randomized algorithm doesn't produce free will either.

Incidentally, all known physical processes --- or, in other words, all possible computing devices in the universe, including human neurons --- can be modeled using some combination of deterministic and stochastic processes. So, even if free will could conceivably exist, actual human beings certainly would not possess it. However, I believe that the very concept of free will is incoherent, an argument that does not depend on properties of our physical universe.

If you disagree with this analysis, it can only be because you misunderstand algorithms, or you misunderstand randomness, or you do not understand how these two combine, or you are defining free will in some tendentious fashion. This seems to be the case, for example, for most of the philosophical positions described in the Wikipedia entry on free will. Notably, none of the pro-free-will arguments that I've ever seen manage to distinguish human decision-making from, say, a program that repeatedly generates a random array, and then sorts that array using an implementation of quicksort that selects a random pivot on each recursion. If you believe that quicksort with a random pivot possesses free will, I suggest that you've redefined free will away to the point of uselessness.

Now, given that free will is philosophically incoherent, I'm not surprised that definitions of free will turn out to be useless, but still, it's sort of sad. Just give up already!


  1. Agreed. Still, it is a weird thing to think about.

    Have you read the book "The Illusion of Conscious Will"? Definitely worth picking up if you're into this stuff.

    The basic story is that there are a number of experiments that show (via monitoring the brain) that when people make decisions, it's generally done unconsciously first, and then a bit later the conscious mind picks up on the decision and thinks, "yeah, that's what I'll do". I read the book a while back, and I do remember some methodological flaws in some of the experiments, but on the whole the evidence is pretty sound. (Perhaps there's a big controversy about this issue in the scientific community; I haven't really followed up on it.)

    I like this book because many people who are "pro-free-will" (whatever that is) generally can't believe that their decisions are predetermined, or at least that they are not *consciously* making the decisions "themselves". This book provides empirical evidence that even when you think you're consciously making decisions, you're not.

  2. I think it's even worse than that. Suppose that one were making decisions through some conscious process; suppose that humans didn't even possess a subconscious. So what? That conscious process either follows some predictable scheme (i.e., it is an algorithm) or it doesn't (i.e., it's random) or some combination of the two. So it still wouldn't be evidence of "free will".

    The whole notion of free will seems to stem from a pretty huge blind spot w.r.t. the rules that govern the decision-making process itself.

  3. Oh, absolutely. I'm just saying that some people have trouble believing that concept since they feel so strongly that they are "spontaneously" making decisions "themselves". The subconscious argument is a way to introduce, with evidence, that that isn't even the case given what we already (seem to) know now.

  4. You seem to have learned somewhere that all behavior is either random or deterministic. I'd like to see the proof of that. I'm really interested, not just trying to be contrary. I've just never previously heard that all behavior is limited to these 2 categories.

  5. Everything is some combination of predictability or unpredictability. Behavior is now neither? Come on, Oct 22, 3:46:12.

  6. I read your ID / Scientist post late,(just today) and never got to comment! I believe it must be said that a softball bat would also work well. My daughter prefers Easton Conexion, and it is my contention that the new, evolved aluminum bats will smash more ID proponents more quickly, easily, and with less sting in the hands then the old-fashioned, Louisville Sluggers from the stone age.

    Thanks You!