Kelly Jones wrote:Mitchell, can you understand or explain why Healey doesn't see that "causality" (as defined by Healey interpreting whats-his-name) is a limited view of causality? Do you think his definition of causality is the reason why he thinks non-locality (of whatever) is proof of non-causality? And also why he thinks the singularity prior to the expansion of the multiverse can be caused by nothing at all ?
He does have that broader view - he calls it logical necessity. And as I recall, it's more that he's agnostic about the nature and universality of physical causation. So perhaps the question is, how does he come to even have room for doubt about physical determinism?
First, it's worth appreciating something of where the problems of nonlocality and the Big Bang come from. The problem of the Big Bang arises because, if you extrapolate the expanding universe backwards according to Einstein's equation for gravity (G = 8 pi T), the curvature of space and the density of matter rise to infinity at a time a little over 10 billion years ago. That equation, which is a deterministic formula for finite values of G and T, breaks down when they become infinite, and it's not so easy to change the equation without screwing up in the present. The problem of nonlocality is a little longer to explain, but it similarly poses dilemmas for anyone proposing to derive the ungrounded probabilities of quantum mechanics from a deterministic subquantum theory. Bohm's theory, for example, throws out relativity.
It might have been better all around if Bohm's theory had nonetheless become orthodoxy, and Bohr's school (uncertainty principle, etc) had been the dissidents. The basic problem of theoretical physics would then have been - and could still be regarded as! - a matter of reconciling two straightforwardly causal and objective theories (Einsteinian gravity and Bohmian mechanics), rather than a lot of "what if" stuff - what if events don't cause other events but only cause probabilities, what if the particle isn't really anywhere definite at all, etc - which might be described as the speculative abandonment of basic principles of thought. (I think I've seen you castigating Laird for this, on other threads.)
The main problem with this view is that what I'll call the metaphysical apriori really can go too far. By this I mean the categories in terms of which the empirical is framed. A crude example would be the idea of extra spatial dimensions. On occasion throughout history this was rejected as inconceivable and therefore impossible, but in fact there's nothing wrong with the idea. Furthermore, the abandonments of causality, identity, etc which disfigure 20th-century physics were not made whimsically, but because of difficulties intrinsic to theories whose mathematical framework arose from empirical considerations. Example already mentioned: the idea of a beginning to time ('Big Bang'), arising out of determinism and field theory. There is a very interesting interplay between mathematics, metaphysics, experiment, incredulity and imagination here, and it seems that no one has yet managed to reason out, ahead of time, the form of all possible worlds (or to put it another way, the set of all theories worthy of consideration).