Summary |
'Interpretations' of quantum mechanics are traditionally characterized by their responses to the measurement problem: how can the deterministic unitary quantum dynamics, expressed in the Schrodinger equation, give rise to particular sequences of measurement outcomes with probabilities given by the Born rule? But the main competing responses to the measurement problem are not interpretations of some agreed core theory; rather, they are logically incompatible theories which generally posit some additional dynamical structure over and above the unitary dynamics. For example, Bohmian mechanics adds 'hidden variables', such as particles with precise locations, which are guided by a field with the same structure as the unitary quantum state; and dynamical collapse theories posit a new stochastic dynamical process of state collapse. An important exception is Everettian quantum mechanics, or the 'many worlds interpretation', which adds no new structure and instead attempts to recover determinate measurement outcomes perspectivally. |