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?
Honestly, I've always thought of free will from the perspective of the past. Someone before I was born essentially has everything they've done "locked in" to history, and if you look at the present in a similar way, then free will doesn't actually exist. To a person 100 years from now, your actions are just as locked in as a person 100 years ago is to you. And at least right now, there's no going back in time and changing that. I know the "destiny" of those of the past merely because I live in a time after.
But, and this is an important but, in that same way, it doesn't mean we act as if people don't have control over their behavior. While the course of things might be already set in the grand scheme of life, those actions were still your actions. Destiny in this sense doesn't work like "You were destined to die on april 7th 2044" no matter what. Your choices with the upcoming future will have consequences that impact the world. Even if you aren't real and your actions weren't "yours" in the historical sense, they still were by any general meaning of the words. I'd blame a person in the 1900's for being a racist piece of shit no matter if it's already locked in or not.