Page:Ferrier's Works Volume 1 - Institutes of Metaphysic (1875 ed.).djvu/287

RhPROP. X.———— we might prove that self could not be known as material, or as a presentation of sense; but unless the postulate were also true that self must be known along with all the sensible presentations, we should be equally deprived of a rational ground for our conclusion. But these two premises are now established institutional articles; and it is conceived that, taken together, they afford an impregnable demonstration of the proposition before us.

2. Tenth Counter-proposition.—"Nihil est in intellectu quod non prius fuit sensu"—that is, "Nothing but mere objects of sense can ever be objects of cognition; in other words, whatever has a place in the intellect can contain only such elements as have had a place in the senses: or otherwise expressed—the senses, by themselves, and the senses only, are competent to place any knowable or intelligible thing before the mind." This counter-proposition is certainly, in the highest degree, consonant with our natural, or ordinary, or unphilosophical habits of thought.

3. The well-known limitation of this maxim by Leibnitz, who, to the words "nihil est in intellectu quod non prius fuit in sensu, " added the restriction, nisi ipse intellectus may, perhaps, deserve a passing comment. Had Leibnitz said that intellect