Read "The Emperor's New Mind" by Roger Penrose for a critique of strong AI. (Strong AI in its sense of consciousness being no more than some very complicated algorithm) His basic argument is that the way that computers work is very very different from the way that our brains work. Computers use algorithms for everything, and Penrose argues that there are some important aspects of human consciousness that are non-algorithmic.

For example, Godel's theorem states that there are some mathematical propositions that can neither be proved nor disproved in any given logic system (ie, using some algorithm to show they follow from the axioms). But humans can intuitively recognize the truth of some of these propositions. This implies that human consciousness consists of more than a mere algorithm.

My main problem with strong AI is that it's impossible to decide whether a computer is conscious/intelligent when a proper definition of consciousness doesn't exist.

Joe