Does Current Science Support Determinism?

Jerry Coyne broke his promise and talked about free will again. Twice, actually, but I want to focus on one section of his reply to Eric Macdonald’s attempt to argue free will, which I have not read myself.

Anyway, the section is this, in reply to a comment that Coyne might be taking his acceptance of determinism as a basic truth as opposed to a scientific/evidenced position:

I don’t think that the principle of determinism “can find no defense.” Nor is it “an article of scientific faith.” Its defense is twofold: it works and, except for actions on the quantum scale, we know of nothing that isn’t predictable in principle. All the progress science has made on the macro scale rests on the idea that given absolutely identical physical conditions acting on an object, its response will always be the same. If this principle didn’t work, we couldn’t get rockets to the Moon. I accept the fact that quantum events, like the location and momentum of electrons or the moment when an atom of a radioactive element decays, can be absolutely unpredictable. But I doubt that this unpredictability has observable results on the scale of human behavior. Physical determinism at the macro level is simply something that works and makes accurate predictions about the universe, and therefore is not an article of faith.

So, this does raise the question: is it actually supported by the models and the evidence in the right way for Coyne to have such confidence? I think that there are a number of problems with this sort of analysis:

  1. Note that Coyne has to constantly say “… except for quantum mechanics.” when he says that everything is predictable in principle or is deterministic.  What this means is that we’ve already found something in the universe that isn’t deterministic.  Determinism gets a lot of support from science when it can say — like naturalists say — that everything we’ve found has been that way before.  When we’ve found an exception to determinism, that claim can’t be made, and so one big piece of evidence is lost.  Science, then, by finding an exception weakens the evidence in favour of determinism.
  2. Coyne divides the universe into the quantum and the macro, and lumps the behaviour of humans into the macro.  But looking at the first point, we can question if — in this case — the macro really is uniform.  It seems that we can at least provisionally divide the macro into the intentional macro — ie things that we claim has or might have intentions — and the unintentional macro.  And then when we look at all the work that’s been done on the macro, we see that it’s been done on the unintentional macro.   All of the sciences except for psychology — which probably isn’t really a science, but tries to be scientific — and some parts of biology deal exclusively with things that we don’t claim have intentions.  But it’s only things that have intentions that are claimed to have free will.  So we don’t have any reason to be certain that what we see in the unintentional macro applies to the intentional macro, especially when it comes to the thing that divides them — free will.
  3. So, what is the evidence from the fields that focus on the intentional?  Not really in support of determinism.  We’ve gotten influences from genetics and environment, but all of psychology and neuroscience has currently is probabilites; a person P is likely to do behaviour B under certain conditions.  Now, of course, this could certainly be attributed to the incredibly complexity of human behaviour, but I don’t see why at this point anyone should just accept that as the answer.  Especially when psychology is forced to “trick” their subjects because if they let them know what they’re doing they could no longer actually run a scientific experiment, and especially since the most deterministic approach to psychology — behaviourism — failed miserably.
  4. A final point can be made from an evolutionary standpoint.  Humans spend a lot of resources deliberating and making decisions.  By evolution, such a massive energy outlay has to have some benefit to be selected for and survive.   It must be the case, then.  that our conscious deliberations change our action in some way that could be selected on.  But if our choices are predetermined, what could that be?   Well, from studying neural networks it could be a useful feedback loop to find inputs to feed into the next iteration to produce the right answer at the end.  But the issue is that if that’s true as long as our deliberations produce the right neural inputs they don’t have to be accurate at all.   When we think that we decide on a major using reasoned arguments, the underlying activations could actually be “I like hamburgers”.  The conscious phenomena, then, wouldn’t have to map to anything real.  This also means that our mental experiences wouldn’t have to either; as long as the neurons work out the same, it doesn’t matter what the consciously experienced data is. Thus, conscious experience would be utterly epiphenomenal; it doesn’t matter at all (or, at least, wouldn’t have to).  But, then, how did it get selected, since it in and of itself doesn’t provide any benefit to the action? It would have to be a side effect, but that’s a lot of energy to put into a side effect.  So the alternative is to think that the conscious deliberations really do matter … but that leads us into thinking that some sort of meaningful choice is made, which leaves one either a libertarian or a compatibilist.

So, it seems that science doesn’t support determinism all that well, and certainly not as well as it used to.  How, then, can Coyne be so convinced of it based on the science?



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