Full Idea
If the naïve inductivist says we should see well-established regularities among our observations, and take that to be the law or causal connection…this will not help us to infer the existence of unobservable entities.
Gist of Idea
If we only infer laws from regularities among observations, we can't infer unobservable entities.
Source
Alexander Bird (Philosophy of Science [1998], Ch.8)
Book Reference
Bird,Alexander: 'Philosophy of Science' [UCL Press 2000], p.239
A Reaction
The obvious solution to this difficulty is an appeal to 'best explanation'. Bird is obviously right that we couldn't survive in the world, let alone do science, if we only acted on what we had actually observed (e.g. many bodies, but not the poison).