David Hume Quote

By this means all knowledge degenerates into probability; and this probability is greater or less, according to our experience of the veracity or deceitfulness of our understanding, and according to the simplicity or intricacy of the question.

Part 4 Of the sceptical and other systems of philosophy, Sect. 1 Of scepticism with regard to reason - A Treatise of Human Nature (1739-40) - Of The Understanding