I found Gilbert's discussion of Laplace's demon applied to neuroscience to be very interesting. As he says, it would be silly to believe that everything in the universe was predictable, EXCEPT for the brains of a few apes on one planet. If physics can in fact be calculated from a starting state, the universe has to be pre-determined as Prof. Goodman and Prof. Gilbert discuss (at 38:35).
However, Gilbert goes on to explain that uncertainty saves the day and "preserves free will", as it's not actually possible to "predict [the state of the universe] at moment X+1 because there's inherent uncertainty". While this is true, these uncertainties occur at the quantum scale, and it has not yet been shown that they meaningfully influence the behavior of nerve cells, which are 10^10 times larger. But even if this was the case, the brain is (probably) a chaotic system, meaning it might still be possible to argue for free will even if uncertainty had no meaningful impact. I'd love to have asked Gilbert whether he thought quantum uncertainty played a major role in brain functions, and whether his answer to that question dictated his answer to the larger question of free will.
This is such a lovely post that makes me appreciate the intersection between psychology, physics, and philosophy. I am very confused on whether we have free will and there are great insights from the quantum world and larger scales. Einstein modeled the universe as a set of points representing events in space and time (technically, a 4-dimensional pseudo-Riemannian manifold with a torsion-free connection---super interesting stuff and I recommend those unfamiliar to look into this!). However, these event points are inherent in the mathematical structure meaning all moments in space and time have been laid out and thus it seems we have no say on the spacetime evolution of the universe. At first glance, this can be in conflict with quantum mechanics due to the uncertainty principles but I second Eric's post: "If our exact actions can't be predicted due to inherent uncertainty in the system, would that imply that our actions are in part governed by randomness? If this is the case, then is that really free will either?". Sure, the quantum is probabilistic and the manifold does not appear to be so as we zoom out but both theories seem to be telling us the same thing in different ways, that is the nonexistence of free will. I am still unsure on whether I agree with this but at least there is food for thought.
"Yes" on all of this... "uncertainty" can exist on many spatial and temporal scales, for many reasons. It's true that quantum uncertainty exists on the tiniest spatial and shortest temporal scales, and that ultimately it could have something to do with brain function & a deep level of "unpredictability." My guess, though, is that larger spatial scales, and longer time scales, "chemical" and/or "biological" processes in our brains govern our behavior (and thus free will) "before" we ever get to the quantum effects. But, that's just my guess!
Hey Gavin, I found that part of the conversation to be particularly interesting too! It prompted me to wonder why we necessarily consider inherent uncertainty/randomness to equate to free will. If our exact actions can't be predicted due to inherent uncertainty in the system, would that imply that our actions are in part governed by randomness? If this is the case, then is that really free will either?