 In the past, taking aspirin has relieved my headaches, so I believe that taking aspirin will relieve the headache I’m having now. But my inference is based on the aspirin’s superficial sensible qualities, which have nothing to do with headache relief. Even if I assume that the aspirin has “secret powers” that are doing the heavy lifting in relieving my headache, they can’t be the basis of my inference, since these “secret powers” are unknown.