Page:Ferrier's Works Volume 1 - Institutes of Metaphysic (1875 ed.).djvu/571

Rh evidence is ever obnoxious to vicissitude; its acceptance or rejection is determined by the humours or idiosyncrasies of individual minds; it comes home to us more forcibly at one time than at another. It varies with the variation of our feelings and our partialities. But the demonstrated truths of philosophy stand exempt from all these disturbing influences. They enlist in their favour neither wishes nor desires. They appeal not to the feelings of men, but simply to their catholic reason. The mind may fall away from them; but they can never fall away. Human passion cannot obscure them; human weakness cannot infect them; but, when once established, they enjoy for ever an immunity from all those mutations to which the truths of mere contingency are exposed.