The principle of least action and teleological explanation in physics

The principle of least action (PLA) has often been cited as a counterexample to the dominant mode of causal explanation in physics. In particular, PLA seems to involve an appeal to final causes or some other teleological ideology. However, Ben-Menahem (Causation in science, Princeton University Press, Princeton, 2018) argues that such implications no longer apply given that PLA can be recovered as limiting case from quantum theory. In this paper, I argue that the metaphysical implications of PLA-based explanations are not undermined by its status as derivative. However, I contend that PLA functions as a diachronic constraint that licenses explanations by constraint (Lange, Because without cause: non-casual explanations in science and mathematics. Oxford University Press, Oxford, 2016). PLA-based explanations, on this account, are non-causal but also differ from familiar cases of teleological explanations in several respects.

Automated summary

The principle of least action (PLA) is often seen as contradicting the dominant causal explanation in physics with its appeal to final causes. However, it has been argued that this implication no longer holds as PLA can be derived from quantum theory. This paper argues that the metaphysical implications of PLA-based explanations remain valid and that PLA functions as a diachronic constraint allowing for non-causal explanations.