David Hume

“ Tho' the mind in its reasonings from causes or effects carries its view beyond those objects, which it sees or remembers, it must never lose sight of them entirely, nor reason merely upon its own ideas, without some mixture of impressions, or at least of ideas of the memory, which are equivalent to impressions. When we infer effects from causes, we must establish the existence of these causes; which we have only two ways of doing, either by an immediate perception of our memory or senses, or by an inference from other causes ”

“ To give an instance of this, we may chuse any point of history, and consider for what reason we either believe or reject it. Thus we believe that Cæsar was kill'd in the senate-house on the ides of March ”