Blindsight

Book 1 in the Firefall series. A far future spaceship ride with rollercoaster energy.

Siri Keeting has severe epilepsy as a child. He undergoes surgery that removes one hemisphere of his brain to control the seizures. Many years later he crews on a spaceship as an observer/reporter because his unique brain function means he can stay emotionally distant from unexpected strange events. And those unexpected events keep piling up. The crew are all augmented in some way, as Siri has also been (after all he's got half a skull they can put stuff into), The ship's captain is inbuilt AI, the nominal commander is a resurrected vampire (so able to make harsh decisions), the linguist has four people's swapable intelligences in her brain, another crew member is in love with one of her personalities, and then there's some rather dangerous aliens. Perhaps I should have mentioned them earlier. Watts increasingly focuses in on what it means to have intelligence vs self awareness. The pace of the action speeds up as the story progresses into a frightening conflict, as does Watts' demands on the reader as his arguments deepen.

One caution. I got about fifty pages into the book and had to look up the Wiki page to sort out who these characters were. The writing is very dense and the people tend to get a bit submerged.