Turing machines

• mathematical abstract model of human action process (what we call computation)

• have program (instructions), inputs, and states

• enumerate an alphabet (program states)

• requires unlimited tape (memory)

• can a program tell whether it will end (halting problem)

• can a program tell whether an output will ever be an input? (undecidability)

• see Turing completeness: the ability to simulate any turing machine (like a meta-turing machine)

• we (humans) are turing complete!

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• read GEB