Udik

makes you look at living beings as software, and at the world as an immense optimization algorithm.

Permutation City is probably the best hard sci-fi novel I've ever read.

the perfectly rational idea that the mind is computable is rife with apparently unsolvable paradoxes.

I think that in the third act Egan added some weaker elements both as a corollary of the idea being explored and as a way of introducing some traditional action, in a novel that is otherwise mostly the setup of an elaborate thought experiment. Nonetheless, I think the result is extraordinary, because the problems posed, the paradoxes highlighted, and some brilliant insights, are new and valid outside the fictional world created in the novel.

Maths, logic, patterns, artificial intelligence, beauty, art and self-referentiality.