fbs7 said:
I have always been quite curious how physicists reconcile the concept free will with the determinism of physics.
The term
free will is commonly used to refer to at least two things. One is that we obviously consider alternative courses of action. This
isn't incompatible with determinsim. The other is that our actions could have, given identical antecedent conditions, resulted in different consequences -- or that, given identical antecedent conditions, we could have thought and acted differently than what we did. This
is incompatible with determinism, and amounts to an assumption that our universe is evolving indeterministically.
fbs7 said:
By determinism I mean the one at macroscopic level, because I know that at quantum level most of the things are based on probabilities. So there's no free will for an electron.
There's no known
quantum level of events. There's only, as far as can be objectively known and unambiguously communicated, a macroscopic level of events. The indeterminism of quantum experimental events is realized at the macroscopic level -- the level of instrumental behavior amenable to our sensory apprehension.
fbs7 said:
But, at macroscopic level, everything seems to have some equation that determines its future, even if that's chaotic and very difficult (for us) to predict.
Not so wrt the macroscopic apprehension of quantum experimental events. Radioactive decay is random, unpredictable. Does that mean that nature is fundamentally indeterministic? Not necessarily. There's just no way to ascertain it one way or the other.
fbs7 said:
... if I'm to believe in physics determinism, I should give up on the concept of free will ...
Not necessarily. As noted above. I believe in, currently assume, a fundamental deterministic evolution of our universe, but I also think that the term
free will has a certain meaning compatible with that assumption.
fbs7 said:
So how do physicists answer that dilemma - is there free will in physics?
It isn't necessarily a dilemma. It just depends on how the term is defined. Ie., one can assume a fundamental determinism (and there seems to be compelling evidence for this assumption), while still entertaining a connotation of the term
free will that's compatible with that assumption. Ie., our choices and actions
are causally linked to certain subsequent events.
One conception, phrasing, of
free will is that you could have, given identical antecedent events, chosen/done otherwise. The problem with assuming this is that there's absolutely no evidence for it. All that's known is a certain set of antecedent conditions, a certain subsequent set of actions, and a certain subsequent set of conditions -- all of which is compatible with the assumption of a fundamental determinism.
Bottom line -- our universe doesn't appear, taking into account all observational evidence, to be evolving indeterministically. So, a fundamental determinism is assumed, which is compatible with a certain connotation of the term,
free will.