In computability theory, the Church–Turing thesis (also known as the Turing–Church thesis, the Church–Turing conjecture, Church's thesis, Church's conjecture, and Turing's thesis) is a hypothesis about the nature of computable functions. It states that a function on the natural numbers is computable by a human being ignoring resource limitations if and only if it is computable by a Turing machine. The thesis is named after American mathematician Alonzo Church and the British mathematician Alan Turing.