A propos determinism: I recently looked into John Searle’s latest (2007) book, Freedom & Neurobiology. As usual, he gets his knickers into the traditional twist that comes from being a physical determinist and an unacknowledged romantic dualist. In this connection, the following line of reasoning occurred to me.
Searle says (p.64) that the conscious, voluntary decision-making aspects of the brain are not deterministic, in effect for our purposes asserting the following. 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.
Searles non-determinist position in respect of free will is 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 Pariss 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) By way of mitigation, however, note that quantum mechanical effects render the literal total determinism position formally untenable and a serious discussion requires assessing how much determinism there actually is. As Mitchell Lazarus pointed out to me, 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 algorithmically (at some level of detail) equivalent consequences may result from a range of 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 a 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.
Where that leaves us is that 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. That the processes underlying our decision-making are as deterministic as physics will allow is, I think, reassuring. It seems to me that this is as good a description of free will as one could ask for. 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. Nor is it the case that it is desirable that the process be non-deterministic. To hold non-determinism to be a virtue would be to argue for randomness rather than consistency in decision-making. Rather, we simply do not have direct perceptual access to the details of its functioning.