 Turing’s response to this kind of argument seems to be that a continuous-state machine can be imitated by discrete-state machines with very small levels of error. Just as differential analyzers can be imitated by digital computers to within quite small margins of error, so too, the conversation of human beings can be imitated by digital computers to margins of error that would not be detected by ordinary interrogators playing the imitation game. It is not clear that this is the right kind of response for Turing to make. If someone thinks that real thought (or intelligence, or mind, or whatever) can only be located in a continuous-state machine, then the fact—if, indeed, it is a fact—that it is possible for discrete-state machines to pass the Turing Test shows only that the Turing Test is no good. A better reply is to ask why one should be so confident that real thought, etc. can only be located in continuous-state machines (if, indeed, it is right to suppose that we are not discrete-state machines). And, before we ask this question, we would do well to consider whether we really do have such good reason to suppose that, from the standpoint of our ability to think, we are not essentially discrete-state machines. (As Block (1981) points out, it seems that there is nothing in our concept of intelligence that rules out intelligent beings with quantised sensory devices; and nor is there anything in our concept of intelligence that rules out intelligent beings with digital working parts.)