Ontic theories, such as hidden-variables models and the de Broglie–Bohm interpretation, take the view that quantum objects have objective properties – which means in turn that wavefunctions are ‘real’ entities, having a one-to-one correspondence with properties that don’t depend on their being measured. The Copenhagen Interpretation, on the other hand, is epistemic, insisting that it’s not physically meaningful to look for any layer of reality beneath what we can measure.
