> "Partly because, mathematically, wavefunctions are vectors in a L^2 Hilbert space, which is complex-valued. Squaring the amplitude, rather Ψ∗Ψ=|Ψ|^2 is one way to ensure that you get real-valued probabilities, which is also related to the fact that […]"https://physics.stackexchange.com/questions/280748/why-do-we...