Predictability of output is very much a computing thing. If I try to compute the 11 trillionth digit of Pi in base-7, I should get the same answer every time. If I do not get the same answer, then the device is either malfunctioning (often) or just not a computer at all.

It it sort of assumed our brains are computers, but no one has ever demonstrated this to be the case to any degree. Human brains seem to, at least partially, operate on different principles.