We always presume that objects with like sensible qualities have like secret powers and will produce similar effects.

Nonetheless, Hume observes, “we always presume, when we see like sensible qualities, that they have like secret powers, and expect that effects, similar to those we have experienced, will follow from them” (EHU 4.2.16/33). Since we neither intuit nor infer a priori that similar objects have similar secret powers, our presumption must be based in some way on our experience.