PREFACE.

...so much so that there was almost no use for either the rules or the terms. Added to this was the abuse of these terms in the other branches of philosophy and even in what they call the Higher Faculties original: "Facultatibus superioribus"; at universities of the time, these were the professional schools of Theology, Law, and Medicine, which sat above the "Lower Faculty" of Arts and Philosophy.. From this arose that perverse opinion that Ontology original: "Ontologia"; the branch of metaphysics dealing with the nature of being. is merely a barbarous philosophical dictionary original: "Lexicon barbarum philosophicum"; a dismissive term for a collection of jargon that lacks clear meaning or utility. used to explain philosophical terms, most of which we could safely do without.

Nor did it help the reputation of First Philosophy original: "Philosophiæ primæ"; another name for Metaphysics or Ontology. that Descartes, despairing of the need to define those ontological terms that we cannot avoid using, declared that they required no definition at all. In his opinion, they belong to the class of things that are better understood through intuition than through a formal definition.

As soon as I had set the goal for myself to make philosophy both certain and useful to the human race, I began to investigate the nature of the evidence found in Euclidean demonstrations. I discovered that, besides the logical form which I recently outlined in my Logic The author refers to his own work, Philosophia rationalis sive Logica (1728)., these demonstrations depend entirely on ontological notions. For the first principles used by Euclides are nominal definitions original: "definitiones nominales"; definitions that identify a concept by name but do not yet prove that the thing defined is actually possible., which possess no truth in themselves, and axioms original: "axiomata"; fundamental truths accepted without proof., most of which are actually ontological propositions. Thus, I realized that all Mathematics original: "Mathesin"; here referring to the broad field of mathematical sciences. owes its certainty to First Philosophy, from which it borrows its primary principles. When I then [began] to demonstrate theorems in philosophy—