Proceedings of the Annual Meeting of the Cognitive Science Society

The Principle of Sufficient Reason (PSR) has been an influential thesis since the earliest stages of western philosophy. According to a simple version of the PSR, for every fact, there must be an explanation of that fact. In the present research, we investigate whether people presuppose a PSR-like principle in judgment. Across four studies (N = 1,007 in total, U.S., Prolific), we find that participants consistently presuppose PSR in judgments about candidate explananda. Such judgments predictably track the metaphysical aspects relevant to the PSR (Study 1) and diverge from related epistemic judgments (Study 2) and value judgments (Study 3). Moreover, we find participants’ PSR-affirming judgments apply to a large set of facts that were sampled from random Wikipedia entries (Studies 4). These findings suggest that certain metaphysical judgments play an important role in our explanatory activities, one that is distinct from the role of the epistemic and value judgments that have been the focus of much recent work in cognitive psychology and philosophy of science.