Where No Mind Has Gone Before: Exploring Laws in Distant and Lonely Worlds

Abstract

Do the laws of nature supervene on ordinary, non‐nomic matters of fact? Lange’s criticism of Humean supervenience (HS) plays a key role in his account of natural laws. Though we are sympathetic to his account, we remain unconvinced by his criticism. We focus on his thought experiment involving a world containing nothing but a lone proton and argue that it does not cast sufficient doubt on HS. In addition, we express some concern about locating the lawmakers in an ontology of primitive subjunctive facts and suggest that a ‘mixed’ metaphysics to the lawmaker question might be attractive.

Acknowledgements

We would like to thank Joe Campbell, Michael O’Rourke, and Mitch Stokes, two anonymous referees for International Studies in the Philosophy of Science, and the Department of Philosophy at Duke University for comments and questions that led to this paper’s improvement. We are particularly grateful to Jonathan Bennett for offering some valuable comments on an early draft and to Marc Lange for his detailed comments, patience, and encouragement.

Notes

[1] The set of sentences that we would choose as a complete description of the universe would be the one which best combines simplicity and strength. On Ramsey’s theory (as restated by Lewis 1973, 73), ‘a contingent generalization is a law of nature if and only if it appears as a theorem (or axiom) in each of the true deductive systems that achieves a best combination of simplicity and strength’. In terms of Lewis’s theory of possible worlds, it follows that a generalization is a law of nature at the actual world if and only if it appears as theorem in the system which best traded off simplicity and strength.

[2] Of course, it is not necessarily the case that accepting HS would bring the laws within our epistemic ken. For there is much about the non‐nomic facts that we do not and will not ever know.

[3] We obviously cannot do justice to the detail of Lange’s account in this short discussion; this sketch is meant only to convey the basic flavour of the theory (see in particular Lange 2000, 2005a, 2009).

[4] Of course, one kind of contamination is familiar and unproblematic. Considering the counterfactual, ‘had there been fewer kangaroos, there would be fewer traffic accidents’, clearly and unproblematically directs us to a possible world picked out by its relation to the actual world. No problem. We believe a more pathological kind of contamination is at work in the lone‐proton thought experiments, as we shall explain below.

[5] This isn’t quite right, as Lewis is prepared to allow for small ‘miracles’ to eliminate large divergences in the histories of deterministic worlds. We set this nuance to one side.

[6] Thanks to an anonymous referee for help in clarifying this point.

[7] If the actual world’s history is an essential feature of the closest lone‐proton world (Lange’s stipulation to the contrary notwithstanding), then Lange has just directed us to a world with the same historical facts as the actual world. But a world with the actual world’s history is obviously not a world in which there has never been anything except for a lone proton! That’s trouble: it would seem that the world to which we’re directed by the counterfactual antecedent ‘Had there never been anything except for a lone proton’ is not a world in which there has never been anything except for a lone proton! Instead, it is a world identical to ours in non‐nomic facts up until the time we start (mentally?) depopulating it. If indeed the laws of nature are the same in our world as in the closest lone‐proton world to which we’re directed by Lange’s thought experiment, we suspect that is probably because they agree in this broad swath of non‐nomic history.

[8] Perhaps it is an intuition like those responsible for Sorites‐style arguments—it looks safe for a handful of motivating test cases, but leads to intolerable conclusions. Of course, we do not claim outright that the anti‐HS conclusion is intolerable.

[9] Again, we must bracket complications stemming from determinism requiring miracles.

[10] Remember: a set of truths need only exhibit stability in the face of counterfactual perturbation consistent with that set for it to be stable (clearly, we cannot expect a sentence to remain true had it been false!).

[11] Consider an analogy. A landing party from the USS Enterprise sets down on a remote and desolate planet, devoid of life. Curiously, they find (what appears to be) a brand new Toyota Camry, gassed up and with the keys in the ignition. ‘What luck!’, cries Kirk, ‘A Camry: the most reliable car in humanoid history!’ The Camry can help them complete their mission. But then it occurs to them: can they really count on this apparently reliable car? Aren’t all bets off? After all, they have no idea how the Camry got here!

[12] Well, perhaps an intuition tug‐of‐war is all that can be hoped for. Lange has admitted to us along these lines that he is not overly concerned with converting the committed Humean.

[13] We lack the space to explore these concerns fully in this context.

[14] We follow Lange in recognizing that compatibility may not always be a good thing. He responds to Handfield’s suggestion that essentialism and ‘Langianism’ could be happily married, that ‘this “flexibility” is a symptom of essentialism’s explanatory impotence as far as the laws’ relation to counterfactuals is concerned’ (Lange 2005c, 586). We do not believe we are subject to this sort of objection—at least no more than Lange himself is in taking subjunctives as primitive. Think of us as simply remaining metaphysically wary.