I read this some time back, but began thinking about it again recently. It was tricky tracking it down based on the vague impression I had at the back of my mind, but the re-read was entirely worth it. The incredibly imaginative premise of the story is that the essence of humanity, perhaps what some people would describe as a 'soul', is the ability to observe, to collapse the quantum wave function and resolve superposition into existence. General AI with free will lack this innately human ability, and hence are frozen in a state of superposition when not observed. Putting aside the scientific inaccuracy, the story is chilling, haunting, and dystopic, yet at the same time a gripping, imaginative thriller.