# From Metaphysics to Physics and Back: the Example of Causation

## Abstract

The notion of causation seems especially apt for being a crossroad between physics and metaphysics, in view of a revived interest both for causal notions in general philosophical analysis in general and causal views of quantum mechanics. As far as the latter is concerned, interesting sort of questions naturally arise when the relation between nonlocality and causation is taken into account. Also on the basis of recent classifications of theories of causation, in the paper I first will draw some general remarks mainly of a methodological character, and I will then review the conditions under which nonlocality can be shown to seriously challenge the no-action-at-a-distance requirement that special-relativistic theories are usually thought to embody. In this connection I will turn then to recent work on causal models of EPR. Over and above the specific merits of these models – mainly concerning the refutation of ‘impossibility claims’ about causal models of quantum correlations – a question arises: what sort of conceptual advantage do we obtain in producing causal models for such correlations *in absence of a deeper understanding of the overall structure of the theory*? I will argue that the only way toward such an understanding may be to cast in advance the problems in a clear and well-defined interpretational framework – which means primarily to specify the ontology that quantum theory is supposed to be about – and *after* to wonder whether problems that seemed worth pursuing still are so in the framework.

As a consequence, in the last two sections I will refer to GRW and Bohmian formulations and

quantum mechanics, in order to emphasize essentially two points: (i) the discussion on causality in quantum mechanics should be cast by using the conceptual resources allowed by ontologically unambiguous interpretations of quantum mechanics and *not* on the background of its ‘orthodox’ – hence vague – formulation; (ii) the interpretation-dependence of causal reasoning in quantum mechanics implies different approaches to causality in (the different versions of) GRW and Bohmian formulations.

### Keywords

Covariance Defend Clarification Plague### References

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