apeiron said:
OK, you have lost me there. I'm not even sure if you are making a satirical argument.
No satire-- just putting physicalism into a kind of operator formalism. When one does that, it exposes several hidden assumptions, in particular that P is invertible (so knowledge of a physical state of a mind is identical to knowledge of the mind) and that it commutes with E (so the evolution of a physical state is the same thing as evolution of mind). Those are actually different assertions, neither of which has any solid support.
For example, it is possible that the physical state of the mind is never going to suffice to tell us what is "in" that mind, and it is sheer assumption on our part that it ever could (and there I also echo your points about a reductionist "state" as being a kind of modelers fiction, indeed I extend that as well to the more potent coupling in the systems view). If knowing everything there is to know about the physical state of a mind is still not enough to know what is "in" that mind (imagine even trying to define the meaning of that phrase), then P is not invertible.
Also, one might imagine a situation where P actually is invertible, but does not commute with E. That is the case for invertible matrices, for example. Then if a mental state M evolves into E[M], and we look at its physical expression, we have P(E[M]). If we claim that P is invertible, we can say M = P
-1(Pr<-->Ps), where by Pr<-->Ps I just mean whatever physical interplay between top-down and bottom-up interactions one wishes to imagine. However, we could still only say E[M] = E[P
-1(Pr<-->Ps)], we could not say E[M] = P
-1(E[Pr<-->Ps]). In other words, if we start out with a state where M = P
-1(Pr<-->Ps) does hold, it does not necessarily continue to hold as it evolves, if P does not commute with E. This is the case, for example, in quantum mechanics, where states of known observables do not have to evolve into states of known observables, so even if we can initially invert the observable to obtain the state, we are not likely to be able to do that later on after evolving the observable correlates of the state.
M = Ps <--> Pr - I translate this as the mind contains two constrasting views of causality, that are formed mutually as a symmetry-breaking of ignorance. But I think still the set theoretic view is more accurate.
Indeed, I would say the actual equation must be P(M) = Ps<-->Pr, such that physical language we apply to the mind contains the two contrasting views you mention. The mind itself does not contain those contrasting views, because the mind is just the mind, and is not responsible for our language about it. This is usually a nitpick, but here it becomes centrally important-- we are trying to understand the limitations we impose when we use reductionism, so we should also understand the limitations we impose when we choose any type of language. The mind leading the mind, in effect-- and I'm going to claim that one! (neuroscience: the mind leading the mind.)
My claim on P (models of physical causality) is that Ps = Pl + Pg. So systems causality is local construction plus global constraints.
Yes, I see your point that Ps subsumes Pr, so my notation Ps<-->Pr does not embody that-- I wasn't too worried about the notation, only the issue that one may or may not take a systems approach, what I'm focusing on at the moment is the physicalist element of either.
However I then also claim that global constraints are still implied in Pr - they are just frozen and so can be left out of the modelling for simplicity's sake. Only the local construction has to be explicitly represented.
Yes, I agree here completely. I haven't heard it said from a systems perspective, but I always stress that all laws of physics are differential equations, so are never complete-- there is no "theory of boundary conditions", that is the dirty little secret of the
manual elements of physics. It's the thaumaturgical element.
But you raise an interesting issue just about the need for a formal notation that captures the ideas of systems causality. There is an abundance of notation to represent reductionist constructive arguments, but not really an equivalent for the systems view.
That's an interesting point, and I agree that causality in the Ps and Pr domains is a very important aspect of physicalist thinking. What I'm saying, though, is that we also need a notation for lifting the physical language into a broader language of mind. Simply assuming that the mind is completely describable by its physical correlates strikes me as a good way to shoot ourselves in the foot down the road, and the notation involving P and E operations is intended to draw out the hidden (and unlikely) assumptions being made.