> don't think that imaginary or complex numbers have physical significance. Yeah I'd say that's the most common approach but I think it's misguided. Complex nu

> don't think that imaginary or complex numbers have physical significance. Yeah I'd say that's the most common approach but I think it's misguided. Complex numbers aren't any less physical than any other number. It just turns out that for historical reasons, it makes sense to define observable quantities using self-adjoint operators (which have real eigenvalues, and the latter are used to measure things like energy). But that doesn't mean the rest is not physical. Just because we can't take a picture of an object in the dark, it doesn't mean the object isn't there when the lights are off.