Turing, Searle, & Penrose

According to Alan Turing of ‘Turing Test’ fame (1950), we can have no privileged insight into the state of another entity’s consciousness. Turing taught that we can only evaluate the consciousness of another entity by experiencing the behavior of that entity. If a machine interacts with you in a way that is indistinguishable from the way another human being would interact with you, then you have no logical grounds for regarding the machine’s thinking process as different in any meaningful way from your own. Who knows, as we subject a machine to the Turing Test, that same machine may very well be conducting a Turing Test on us!

John Searle (1980) granted that a machine could conceivably pass a Turing Test, but he argued that that would not prove that the machine had a ‘mind’ in the same sense that we have minds. Searle believed that ‘mind’ requires a recursive loop of the sort that we call ‘intentionality’ or ‘understanding’ – the ability of an entity to reflect on itself as well as on its environment. Searle argued that no machine could be self-aware in this sense.

Roger Penrose (1989) went even further. Essentially, he questioned whether any machine could ever pass a Turing Test (provided the tester knew the right questions to ask). According to Penrose, the human mind is capable of certain mental feats that cannot be duplicated by any ‘program’. He cites Kurt Gödel’s ‘Incompleteness Theorem’ as a prime example. According to Gödel’s theorem, which is proven, mathematics contains certain self-evidently true statements which can never be proved.