The way that we currently build theories in physics is to write down a classical theory, and then ‘quantize it’ (which involves replacing classical numbers with operators and enforcing some non-commutation. Or it involves promoting the idea that the action is extremized with a path integral over the action). String theory is no exception, you typically start with a classical string-action.
Because of this, most of the underlying structure of quantum mechanics comes along for the ride. Unfortunately, this usually leads to formal problems (no one has yet developed a satisfying axiomatic quantum field theory, and the situation in string theory is even worse), but physicists ignore these issues, because such theories, while not formally developed, make the right predictions.
The way that we currently build theories in physics is to write down a classical theory, and then ‘quantize it’ (which involves replacing classical numbers with operators and enforcing some non-commutation. Or it involves promoting the idea that the action is extremized with a path integral over the action). String theory is no exception, you typically start with a classical string-action.
Because of this, most of the underlying structure of quantum mechanics comes along for the ride. Unfortunately, this usually leads to formal problems (no one has yet developed a satisfying axiomatic quantum field theory, and the situation in string theory is even worse), but physicists ignore these issues, because such theories, while not formally developed, make the right predictions.