This topic has been buzzing around my mind for a while, so I figure it's time to externalize it. "Free will is an illusion" is a meme that I've seen quite a lot on this site especially. I don't think most people who repeat it have thought much about it.
Yeah, materialism (which I hear is popular around here) suggests a mechanistic universe, one without true randomness, defined solely by predictable input and output. That contradicts our intuition about independent free will, which seems unpredictable (or at least not fully predictable) when we experience it. I don't think a fully mechanistic universe is incompatible with free will, though - in fact, I think that any coherent definition of free will must necessarily exist even under a materialist lens. Those of you who are (like me) pop-philosophy dilettantes probably know that this position is called "compatibilism".
Obviously, though, people disagree. I want to know why. If you don't believe that free will exists, under what circumstances do you think it would exist? What do you think would change if it did exist according to your definition?
I don't, because I don't think lack of predictability is free will as long as the system is still deterministic. If you ran the same person in the same sim 20 times you'd get the same result. Even if you added an RNG to mix up decision making, that's still not free will, it's just an RNG. Broadly, I can't think of a definition of Free Will I'd accept that does not also break both causality and locality. There would need to be an "air gap" between sensory and rational processes.
On top of that, I expect human behaviour could be predicted at a pretty much perfect level given a known sensory input without creating a conscious simulation of that person.
But what's doing the predicting? Whatever it is, all it's doing is implementing a version of a free willed conscious being. That being has free choice, the only way to figure out what its decision will be is to progress the simulation and perk ahead. If you just keep repeating everything, that being had free choice each time and chose to do the same thing (regardless if it knew it is was in a simulation or more likely that they didnt know), in my view anyway.
If you know enough about someone that you can perfectly predict what theyll do, theres only one way to do that. Make a high fidelity copy of them and run out the simulation - which implies that we all walk around with varying quality copies of loved ones, friends, that we use when considering a gift or what they would have thought and I fully accept that and think it's true (my little strange loop copy of my partner for example isnt very good because I frequently get their order wrong for coffee and stuff). If you mean we can predict human behaviour in the aggregate, yeah I agree, but that doesnt have anything to do with individual free choice. It just means we can generally predict the activity of large enough populations of free actors.
You dont have to accept my premise that consciousness isnt something immaterial or special and that it is a purely mechanistic thing that emerges as a function or a state machine, but if you do then how that function is implemented shouldnt really be affected by if it's being run on biological hardware, in someone else's head, silicon, or being hand cranked out page after page by a room of graduate students. And in every case, there was indeed a conscious being that made free choice. At least that's what I think.
Ok I have several issues with this, but the main one is that you've just defined a rock as having free will.
A rock tumbles through the air due to a complex and hard to see combination of properties, any simulation of a rock is essentially the rock, thus, when we throw a rock we have recreated the qualia of the rock to predict the rock's arc. Even a computer who has watch the rock being thrown a hundred billion times in all sorts of conditions, and just uses a big look up table to see what the rock will do is essentially replicating the rock.