PREFACE.

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...I would attempt to show, intending to derive the predicate from the determinations of the subject through legitimate reasoning, and I would try to reduce principles through repeated demonstrations back to indemonstrable truths. Through this work itself, I learned that in every kind of truth, just as in Mathematics original: "Mathesi"; here referring to the formal, deductive system of the mathematical sciences., one eventually arrives at the principles of First Philosophy original: "Philosophiæ primæ"; the branch of metaphysics now called Ontology..

Thus, I had no doubt that philosophy—and even less so those subjects commonly called the Higher Faculties original: "Facultates superiores"; at universities, these were the professional disciplines of Theology, Law, and Medicine.—could not be taught by a scientific method original: "methodo scientifica"; in this period, "scientific" specifically meant the rigorous, step-by-step deductive method used in geometry. so as to become certain and useful, until First Philosophy itself had been reduced to that same form.

Finally, when I first examined with singular zeal the discoveries of mathematicians, both ancient and modern, and then those of physicists—especially in experimental philosophy original: "Philosophia experimentali"; what we would today call empirical physics or the natural sciences.—considering how they had been deduced (or at least could have been deduced) from certain other presuppositions through specific analytical techniques original: "artificia analytica"; the systematic breakdown of complex problems into simpler elements., I understood that the general rules of the Art of Discovery original: "Artis inveniendi"; the branch of logic concerned with finding new truths or solving problems. must also be demonstrated from ontological notions. In due time, I shall provide ocular proof of this when I set forth the Art of Discovery and reduce the famous discoveries that exist to their proper rules.

Indeed, when I was forming a certain notion and investigating some examples of the Logic of Probabilities original: "Logicæ probabilium"; a logic dealing with likelihood and uncertainty rather than absolute certainty. (which Leibniz Gottfried Wilhelm Leibniz (1646–1716), a major German philosopher and mathematician whom the author follows closely. several times remarked was still lacking), I found no less that without [ontological] notions...