In the last part of this series I said a deterministic brain would generate thoughts based on things like its previous thoughts, its environment, its genetics, and its memories. Practically speaking, though, it would remain unpredictable, even to itself, due to things like chaos theory (which apply even in a completely deterministic Universe).
Since it's the inner workings of a deterministic brain that make decisions rather than an overwhelming force from the outside world, such a brain can be said to have Free Will.
Some people, however, prefer the idea of a mind that can have thoughts without a preceding chain of cause and effect.
I'm assuming for the sake of discussion that we're not talking about a brain that simply has some quantum non-determinism thrown in, because the effect of this on the brain's operation would probably not even approach the existing effects of chaos theory. So we're really talking about a brain that can generate complex thoughts without prior cause.
An extreme case of this would be a person who spontaneously comes up with the theory of relativity without any background in physics. Or a person who sketches out a design for a digital intelligence without any background in A.I. or cognitive science. To the best of my knowledge, no such event has ever been recorded.
Getting to the heart of the matter, my impression is that "Free Will purists" don't believe that a deterministic brain can be creative. While they accept that a deterministic brain can react in simple ways to events, they believe that something special and outside the laws of physics must be responsible for creativity.
So in the next part of this series I'll discuss the essence creativity and how a deterministic brain can be creative.