Archive for April, 2012

Free Will Examined Further

Friday, April 20th, 2012

With respect to free will. Lots of philosophers and scientists (including me in a previous incarnation, having since seen the error of my ways) look to quantum effects as a way to square a completely physical universe with the possibility of free will. As I understand it, quantum phenomena are deterministic in the sense that something determinate has to happen as the end result of the collapse of the quantum wave function. Before the collapse we have a determinate probability density function. I take this to be the unvarnished meaning of Kauffman’s remark that “the quantum-classical boundary [is] non-random yet lawless.”

I agree that this implies that it is literally the case that “no algorithmic simulation of the world or ourselves can calculate the real world.” As my friend Mitchell has pointed out to me, infinite precision is not possible because of uncertainty constraints. Either one believes in a hidden variable theory of quantum mechanics or one does not. If one does, then we’re back to plain vanilla determinism and maybe uncertainty goes away, too. If one does not, then things are still deterministic with a dash of probability thrown in, the effect of which, no matter how “lawful” succeeds only in constraining the randomness a bit—and all of that subject to uncertainty limitations.

I don’t think randomness, even randomness selected from a deterministic probability density function helps a free will argument at all. What we want is responsibility, not random behavior. The only way I have ever seen quantum indeterminacy used as an argument for the possibility of free will is as part of a dualistic program in which mind and the physical universe are distinct. The idea seems to be that the mind gets to tweak quantum outcomes and that is enough to guarantee freedom and responsibility. Too much hand waving at too small a scale, I say. I don’t believe it for a second.

John Searle in his (2007) book, Freedom & Neurobiology worries about the philosophical consequences of physical determinism, too.  Searle says (p.64) that the conscious, voluntary decision-making aspects of the brain are not deterministic, in effect for our purposes asserting that if there is an algorithm that describes conscious, voluntary decision-making processes, it must be (at least perceived as) non-deterministic. Although it would be possible to extend the definition of an algorithm to include non-deterministic processes, the prospect is distasteful at best. How can we respond to this challenge?

Searle reasons (p.57) that

We have the first-person conscious experience of acting on reasons. We state these reasons in the form of explanations. [T]hey are not of the form A caused B. They are of the form, a rational self S performed act A, and in performing A, S acted on reason R.

He further remarks (p.42) that an essential feature of voluntary decision-making is the readily-perceivable presence of a gap:

In typical cases of deliberating and acting, there is a gap, or a series of gaps between the causes of each stage in the processes of deliberating, deciding and acting, and the subsequent stages.

Searle feels the need to interpret this phenomenological gap as the point at which non-determinism is required in order for free will to assert itself.

Searle takes a non-determinist position in respect of free will as his response to the proposition that in theory absolutely everything is and always has been determined at the level of physical laws.

If the total state of Paris’s brain at t1 is causally sufficient to determine the total state of his brain at t2, in this and in other relevantly similar cases, then he has no free will. (p. 61)

As noted above, the literal total determinism position is formally untenable and a serious discussion requires assessing how much determinism there actually is. As my friend Mitchell also points out, in neuro-glial systems, whether an active element fires (depolarizes) or not may be determined by precisely when a particular calcium ion arrives, a fact that ultimately depends on quantum mechanical effects. On the other hand, Edelman and Gally 2001 have observed that real world neuro-glial systems exhibit degeneracy, which is to say that at some suitable macro level of detail equivalent responses eventuate from a range of non-equivalent stimulation patterns. This would tend to iron out at a macro level the effects of micro level quantum variability. Even so, macro catastrophes (in the mathematical sense) ultimately depend on micro rather than macro variations, again leaving us with not quite total determinism.

To my way of thinking, the presence of Searle’s gap is better explained if we make two assumptions that I do not think to be tendentious: 1) that the outcome of the decision-making process is not known in advance because the decision really hasn’t been made yet and 2) that details of the processes that perform the actual function of reaching a decision are not consciously accessible beyond the distinctive feeling (perception?) that one is thinking about the decision. When those processes converge on, arrive at, a decision, the gap is perceived to end and a high-level summary or abstract of the process becomes available, which we perceive as the reason(s) for, but not cause(s) of, the decision taken.

Presumably, based on what we know of the brain, the underlying process is complex, highly detailed and involves many simultaneous (parallel) deterministic (or as close to deterministic as modern physics allows) evaluations and comparisons. Consciousness, on the other hand, is as Searle describes it a unified field, which I take to mean that it is not well-suited to comprehend, deal with, simultaneous awareness of everything that determined the ultimate decision. There is a limit to the number of things (chunks, see Miller 1956) we can keep in mind at one time. Presumably, serious decision-making involves weighing too many chunkable elements for consciousness to deal with. This seems like a pretty good way for evolution to have integrated complex and sophisticated decision-making into our brains.

That the processes underlying our decision-making are as deterministic as physics will allow is, I think, reassuring. We make decisions 1) precisely when we think (perceive) we are making them, 2) on the basis of the reasons and principles we think we act on when making them. It seems to me that this is just what we want from free will. After all, when we say we have free will, we mean that our decisions are the result of who we are, which is in turn the result of several billion years of history in our genes combined with our epigenetic encounters with the world in the form of our own personal histories. If we have formed a moral character, that is where it has come from. When we have to decide something, we do not just suddenly go into mindless zombie slave mode during the gap and receive arbitrary instructions from some unknown free-will agency with which we have no causal physical connection. Rather, we consider the alternatives and somehow arrive at a decision. Nor would it be desirable that the process be non-deterministic in any macro sense. To hold non-determinism to be a virtue would be to argue for the desirability of randomness rather than consistency in decision-making. We do not have direct perceptual access to the details of its functioning, but I do not doubt that what we have is everything one could desire of free will.

[My notes show that this entry dates from July 27, 2009]