Darwin had some very interesting ideas on free will: 
This one seems to express the idea that the capacity for self-directedness is embodied in the physical configuration of the organism, by virtue of what its physical states mean
And that the meaning of any given state is given by the value assigned through interaction with its environment...
Which I think is exactly right. Value (whether a stimulus is good or bad) emerges through action - approach or avoidance - and the verdict of natural selection on whether that action favors persistence
I take this to be the basis for things having meaning and for organisms having real agency - doing things for their own reasons
However, if those reasons are embodied in the physical configuration of our brains, itself a result of evolution, development, and learning, then how much in control of those reasons are we?
Darwin had thoughts on this too, expressing the idea not just that hereditary instincts and dispositions constrain our choices at any given moment, but that their effects cascade over our lifetimes...
This seems right too and is a theme I explore in Innate press.princeton.edu/books/hardcove…
I don't however think that means we don't have free will - all of those configurations, all of that personal history - that IS YOU. Yes, they constrain your actions, but those constraints constitute your self.
If free will = self-directedness, then it is entirely dependent on those kinds of constraints. Free will is not doing things for no reason, but for your reasons.
Who's in charge? You or your brain? (Kevin Mitchell | TEDxTrinityCollegeDublin) ted.com/talks/kevin_mi… via @TEDTalks
