From Metaphysics to Physics and Back: the Example of Causation

Is causal talk meaningful in the foundations of quantum mechanics? The question does not admit a straightforward and model-independent answer. On one hand, I think that we should welcome the acknowledgement – nowadays largely agreed upon – that quantum mechanics does not per se prevent any causal approach: quantum mechanics is not intrinsically ‘less causal’ than any other possible well-defined physical theory and any conclusion concerning causality in quantum mechanics must be evaluated within a well-specified causal framework and with respect a well-defined domain of phenomena. On the other hand, most investigations on causality in the foundations and philosophy of quantum mechanics fail to refer to an unambiguous interpretation of quantum mechanics itself, namely an interpretation that– unlike the standard formulation – clearly specifies the intended ontological content of the theory. Shifting to ontologically unambiguous interpretations of quantum mechanics–such as Bohmian mechanics or GRW theory in one of its variants– might contribute in this respect to a deeper understanding of an hypothetical causal structure of the quantum world, by paying for instance a special attention to the complex ways in which causality is connected to the issue of Lorentz invariance in these interpretations.