There is something unnerving about thinking about myself sitting in a white sterile test chamber, presented with a choice, some arbitrary one: apples or oranges.
But then to imagine myself as a set of cells, particles, atoms carefully re-arranged back to the exact moment before I made my decision. I'm fully convinced that I would make the same decision.
The memories I had prior would be represented by strengthened connections between neurons, synapses etc... It doesn't matter, all of those cells are massive in atomic count and would then be re-constructed to the exact atomic constituents prior to me making my choice. I would by all logic have the exact same memory as before.
The input I would get from my senses would be the same. Controlled. Blank white walls of a test chamber, the table looking the same. Time is of course different. That's the key thought here. That I would have at two separate moments in time decided to act in the exact same way, thinking that I had only acted once. Like some deterministic machine. Albeit a complex machine, but a machine nonetheless: fully deterministic.
The damage is by now already done. Such a test need not really occur (or even be possible) in order to convince me that I am in fact, very much so a set of particles in motion, deterministic.
so... then what am I supposed to think!?
Maybe "quantum mechanics!" can save my notion of "free will"? ... I sure hope so! Hoping that it'll never be possible to fully simulate what goes on at the microscopic level of atoms and electrons with deterministic precision, and therefore minute differences might magnify over time like some sort of butterfly effect cascading within my brain, leading to some other choice being made in repeated experiments, despite all the atoms being "in the right place" every time. In that case I can at least comfort myself in thinking that my finer details are at least generated by "random quantum noise". Lol I'm so random.
But perhaps there's a better way to think about this. That "free will" doesn't necessarily mean an actor can't be deterministic. But perhaps the distinction is only when the determinism becomes observed, that "free will" would imply that no other actor observes and takes advantage of your determinism at a later time. Since surely, the moment your determinism becomes an input to your own sensory processing machine, you can now re-adjust yourself to make a different choice (or the same). A third party that observes this same determinism in you might not decide to show it to you, and instead decide to sell you apples!