Full Idea
All our reasonings concerning matters of fact are founded on a species of analogy, which leads us to expect from any cause the same events, which we have observed to result from similar causes.
Gist of Idea
All reasoning concerning matters of fact is based on analogy (with similar results of similar causes)
Source
David Hume (Enquiry Conc Human Understanding [1748], §82)
Book Reference
Hume,David: 'Enquiries Conc. Human Understanding, Morals', ed/tr. Selby-Bigge/Nidditch [OUP 1975], p.104
A Reaction
Interesting. Analogy notoriously becomes problematical when you have only one case (or a few) to go on, as when inferring other minds, or God's existence from natural design.