  Turing's machine formulation allowed the precise definition of the computable: namely, as what can be done by a Turing machine acting alone. More exactly, computable operations are those which can be effected by what Turing called automatic machines. The crucial point here is that the action of an automatic Turing machine is totally determined by its ‘table of behaviour’. (Turing also allowed for ‘choice machines’ which call for human inputs, rather than being totally determined.) Turing then proposed that this definition of ‘computable’ captured precisely what was intended by such words as ‘definite method, procedure, mechanical process’ in stating the Entscheidungsproblem.