PREFACE.

...is able to weigh it; he will sufficiently understand that our own thoughts have been more useful to us for understanding the ideas of others, than the ideas of others have been for discovering our own. By this very fact, it also becomes known how our own definitions shed light on things said more obscurely by others, so that they might be fully understood. This holds true not only in First Philosophy First Philosophy original: Philosophia prima; the study of the most fundamental principles of reality and being, often used interchangeably with metaphysics, but in all other forms of knowledge. We have given examples of this elsewhere, such as in our Oration on the Practical Philosophy of the Chinese original: Sinarum philosophia practica; a famous and controversial lecture Wolff gave in 1721, praising Confucian ethics and in our Leisure Hours original: Horis nostris subsecivis; a collection of Wolff's shorter academic essays and reflections. We shall provide more examples in the future, both in these very pages and in other philosophical works; those who make our ideas familiar to themselves through tireless study will experience this for themselves.

If there should happen to be any to whom the ontological ontological relating to Ontology, the branch of philosophy that studies the nature of being, existence, or reality principles proposed here seem sterile or of little importance, I would wish them to consider that the usefulness of principles does not appear until they have been applied to demonstrate other things. Therefore, those who judge their utility before they have attempted to apply them—or before an occasion for application has arisen—are rushing to a premature judgment. The elements of Euclid original: Euclidea; referring to Euclid’s Elements, the foundational text of geometry which uses a step-by-step logical structure seem much more "sterile" in isolation, such that no one ignorant of the rest of Mathematics Mathematics original: Matheseos could guess their use. But once you have advanced into the other branches of Mathematics, you discover their utility is so great that you would never have believed it possible. Certain principles concerning quantity original: quantitate, which are here derived from notions...