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?
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.