If you somehow managed to perfectly simulate a human being, they would also act deterministically in response to identical initial conditions (modulo quantum effects, which are insignificant at the neural scale and also apply just as well to transistors).

It's not entirely infeasible that neurons could harness quantum effects. Not across the neurons as a whole, but via some sort of microstructures or chemical processes [0]. It seems likely that birds harness quantum effects to measure magnetic fields [1].

0: https://www.sciencealert.com/quantum-entanglement-in-neurons... 1: https://www.scientificamerican.com/article/how-migrating-bir...

Doesn’t everything act deterministically if all the forces are understood? Humans included.

One can say the notion of free will is an unpacked bundle of near infinite forces emerging in and passing through us.

Doesn’t everything act deterministically if all the forces are understood? Humans included.

> in response to identical initial conditions

precisely, mathematically identical to infinite precision .. "yes".

Meanwhile, in the real world we live in it's essentially physically impossible to stage two seperate systems to be identical to such a degree AND it's an important result that some systems, some very simple systems, will have quite different outcomes without that precise degree of impossibly infinitely detailed identical conditions.

See: Lorenz's Butterfly and Smale's Horseshoe Map.