 Essentially, then, the Church-Turing thesis says that no human computer, or machine that mimics a human computer, can out-compute the universal Turing machine. However, a variety of other propositions, very different from the Church-Turing thesis properly so called, are from time to time dubbed the Church-Turing thesis (or Church’s thesis)—sometimes, but not always, with accompanying hedges, such as ‘strong form’ and ‘physical version’. For instance, the claim that the universal Turing machine can do any mathematical task that can be done by any machine—a claim very different from Turing’s—is sometimes referred to as the Church-Turing thesis.