Eu acho que a única explicação dada é que quando Mike tem o mesmo número de "neurônios" que um cérebro humano tem neurônios, ele acorda.
They kept hooking hardware into him ... Human brain has around ten-to-the-tenth neurons. By third year Mike had better than one and a half times that number of neuristors. And woke up.
Somewhere along evolutionary chain from macromolecule to human brain self-awareness crept in. Psychologists assert it happens automatically whenever a brain acquires certain very high number of associational paths. Can't see it matters whether paths are protein or platinum.
The Moon Is a Harsh Mistress, p. 7 (Ace paperback edition?)
Lá vai você: "Os psicólogos afirmam."