 Hume spells out the circularity this way. Any reasoning that takes us from (1) to (2) must employ some connecting principle that connects the past with the future. Since one thing that keeps us from moving directly from past to future is the possibility that the course of nature might change, it seems plausible to think that the connecting principle we need will be one that will assure us that nature is uniform—that the course of nature won’t change—something like this uniformity principle: