Re: Dennett vs. Harris on Free Will
It is hard to follow, that's part of the debate, trying to set the definitions straight of what we mean -- or should mean -- by free will.
Harris is basically giving the standard argument that if you accept a deterministic universe (even allowing for say, random quantum events), then any decision is based on your brain state at the time, which was caused by your previous brain state, and so on (and of course your environment and other choices affect your brain state). So there's no room for "free" choice outside of this causal chain, even though we have the "illusion" that we could have acted differently.
Dennett is trying to argue for a notion of free will that is consistent with determinism, and is basically saying that Harris's definition of free will is not a useful one.