 Now, if one accepts (i), then the problem of induction reveals two (related) problems: (a) one concerns the connection among sensible qualities, and (b) the other concerns the connection between hidden qualities and the visible qualities. So, if one accepts (i), one might have thought, for example, that routinely (if not exception-less) conjoined sensible qualities must always presuppose the same combination of hidden/invisible qualities that produce them. So, one could solve the problem associated with (a) by an appeal to hidden qualities. In thinking this one could, in fact, appeal to a same effect/same cause principle of the sort Newton articulates in the second rule of reasoning: “to the same natural effects we must, as far as possible, assign the same causes”. To be sure, Newton’s version of the rule recognizes exceptions and is clearly regulative (“as far as possible”) and it does not rely on (i). Rather, in Newton the rule is a direct consequence of a parsimony principle (“admit no more causes of natural things than such as are both true and sufficient to explain their appearances”).