Using your logic, Alonzo Church should be credited with the Turing machine and the halting problem since he solved Hilbert's Entscheidungsproblem before Turing

Using your logic, Alonzo Church should be credited with the Turing machine and the halting problem since he solved Hilbert's Entscheidungsproblem before Turing did. If everything follows trivially from an answer to the same question, then Turing's solution follows trivially from Church. Not sure why you are fixated on the Entscheidungsproblem. Turing's claim to fame isn't the entscheidungsproblem. If it were, nobody would know who Turing is because Church already solved the entscheidungsproblem. His contribution are the theoretical concept of Turing machines ( universal turing machines especially ) and computable numbers. > Did Turing's original machine not have a halting state? Are you asking me? > You can hardly express the halting problem if you don't have the concept of halting. He did have a concept of halting. He called them circular/unsatisfactory. Did you even read his paper?