 There is an even more fundamental relationship between Hume’s conception of the inductive method and Newton’s Rule 3. In the explanation of this Rule (as we have seen) Newton takes the supposition that “nature is always simple and ever consonant with itself” to license the inductive generalizations made in accordance with the Rule. Similarly, Hume appeals, in the Enquiry, to the supposition that “the course of nature” does not change (EHU 4.21; SBN 37–38) or, equivalently, that “the future will be conformable to the past” (EHU 4.19; SBN 35–36). In the Treatise Hume formulates this supposition as the 