If you could simply program a human's behavior into a machine, that would be fine, but humans aren't capable of encoding their neural circuitry in a programming language; in fact, the combined efforts of all humans have only begun to shed light on what human behavior is. As such, generating formalized information (that describes behavior) requires some process (other than human hands) to do it -- and in the case of a machine that interacts with the world, "turing machine" is not a complete description of any such process.

By Shannon's information theory, everything is bits of information. Completely irrelevant for the mechanism of a Turing Machine is, who writes the initial bits on the tape. For all I care, the world is the tape and the computer is the head being moved through it. It's the old fallacy seeing the brain as a computer, since we've build computers after structures from our brains. Hence I wondered, what more there should be.