Complex sentence: Probability amplitudes provide a physical meaning of the wave function (or, more general, of a quantum state vector), a link first proposed by Max Born, and this is a pillar of the Copenhagen interpretation of quantum mechanics.
Split into simpler sentences: Probability amplitudes provide a physical meaning of the wave function (or, more general, of a quantum state vector), a link first proposed by Max Born. Interpretation of values of a wave function as the probability amplitude is a pillar of the Copenhagen interpretation of quantum mechanics.