“Why not see both the probabilistic independence assumption and the common-cause principle as mutually dependent aspects of causal structures? We can accept that these structures have an important role to play in physics, just as they do in other sciences and in common sense, without having to commit to the metaphysical priority of either.”
“This third view is reminiscent of the late US physicist Richard Feynman’s view about physical laws. Feynman argued that the laws of physics do not exhibit a unique, logical structure, such that one set of statements is more fundamental than another. Instead of a hierarchical ‘Euclidean conception’ of theories, Feynman argued that physics follows what he calls the ‘Babylonian tradition’, according to which the principles of physics provide us with an interconnected structure with no unique, context-independent starting point for our derivations. Given such structures, Feynman said: ‘I am never quite sure of where I am supposed to begin or where I am supposed to end.’”
“I want to suggest that we should think of causal structures in physics in the very same way. Contrary to Russellian skeptics, causal structures play as indispensible a role in physics as in other sciences. And yet we do not need to take sides in the debate between Einstein and Ritz. Derivation doesn’t have to start anywhere in particular. Rather, we can understand the probabilistic independence assumption and the causal asymmetry as two interrelated aspects of causal structures.”
“This final view, however, presupposes that we agree with Hume that our use of causal reasoning is not underwritten by any kind of metaphysical ‘glue’. As Hume taught us, causal representations are incredibly useful – we couldn’t get very far in the world without them, in physics or elsewhere. But this doesn’t mean we must believe in a richly metaphysical idea of causal powers, ‘producing’ or ‘bringing about’ causal regularities like muscular enforcers of the laws of nature. We still see only the patterns, the constant conjunctions of different sorts of event.”
“It’s a vaguely unsettling thought, isn’t it? But that might be enough.”