Turing test identification" by correctly identifying the machine as being just that. If however a machine remains silent during a conversation, i.e. takes the fifth, then it is not possible for an interrogator to accurately identify the machine other than by means of a calculated guess. Even taking into account a parallel/hidden human as part of the test may not help the situation as humans can often be misidentified as being a machine. Mainstream AI researchers argue that trying to pass the Turing test is merely a distraction from more fruitful research. Indeed, the Turing test is not an active focus of
Church–Turing thesis three formally-defined classes of computable functions coincide with the "informal" notion of an effectively calculable function. Since, as an informal notion, the concept of effective calculability does not have a formal definition, the thesis, although it has near-universal acceptance, cannot be formally proven. Since its inception, variations on the original thesis have arisen, including statements about what can physically be realized by a computer in our universe (physical Church-Turing thesis) and what can be efficiently computed (Church–Turing thesis (complexity theory)). These variations are not due to Church or Turing, but arise from later work in complexity theory and digital physics.