 While there might be ways in which the details of Tipler’s argument could be improved, the general point seems clearly right: the kind of combinatorial explosion that is required for a look-up tree for a human being is ruled out by the laws and boundary conditions that govern the operations of the physical world. But, if this is right, then, while it may be true that Blockhead is a logical possibility, it follows that Blockhead is not a nomic or physical possibility. And then it seems natural to hold that The Turing Test does indeed provide nomically sufficient conditions for the attribution of intelligence: given everything else that we already know—or, at any rate, take ourselves to know—about the universe in which we live, we would be fully justified in concluding that anything that succeeds in passing The Turing Test is, indeed, intelligent (possessed of a mind, and so forth).