Although I confess I have only read the first chapter or so, the book sets out to convince its readers that many of the things that can go wrong in the human brain ought not to be thought of as bad choices so much as automobiles in need of a part replacement (this metaphor rings true today in the case of, say, depression, which can often be remedied with pharmaceuticals). This may sound rather weak (especially from the point of a prosecutor [1]), but when looking at the details, it starts to make sense in a lot of cases.
For example: in the middle ages, what do you think people thought schizophrenia was?
I think of it like this. Perhaps every decision you make is /almost/ entirely determined by your current biological state and a long string of preconditions beyond your control. But… there is a sliver of freewill on top of this. And /with/ that sliver, you can choose to make incremental changes to your personal beliefs which molds your perception. By doing this, you essentially alter your biological state in a small way. This effect is cumulative, so you eventually start making different decisions than you would have, which changes your environment, and thus further changes the preconditions of your future. In this way, I believe freewill itself is cumulative. You are born with almost none, but you can develop it incrementally with effort.
No, this is a generalization. Without getting into a discussion on determinism you can call a "choice" a decision that a person is able to ponder, discuss, explain.
People can be temporarily pushed out of the ability to make rational decisions in many ways. Examples abound.
Correction: Examples infinite. If you're going to venture anywhere outside the realm of split-second fight-or-flight behavior such as with drug addiction or suicide, then you can rationalize anything as out of your control. You can also choose to take responsibility for your own actions; and let others take responsibility for theirs, rather than trying to rationalize away their agency, or yours.
