Usually attributed to Dijkstra.
To be fair, theory of computation is more logic/proofs/formalism than what is mistakenly associated with CS nowadays - programming. Besides isn't everything just philosophy at the end of that day?
> The professor knew almost nothing about actual computers.
The foundations of theory of computation were laid before actual computers.
> Which was pretty cool, honestly.
I can't imagine my philosophy professors teaching theory of computation as they too didn't know anything about computers. But I'm sure they would have made it interesting.
They had to run it for a few years before they realized CS kids who did poorly in the class dropped the major - the implicit signal being "you don't know how to think like a computer scientist".