PREFACE.

...ciples deduced a priori a priori original: a priori; reasoning or knowledge which proceeds from theoretical deduction or first principles rather than from observation or experience, those are the ones into which all the universal Euclidean elements Referring to the fundamental geometric principles established by the Greek mathematician Euclid, which Wolff viewed as the gold standard for logical demonstration are resolved, and from which they—and indeed the whole of mathematical science mathematical science original: Mathesis; in the 18th century, this term referred to the broader study of quantity and order, often seen as the model for certain knowledge—derive all their clarity. Moreover, the other philosophical disciplines expect their own principles from ontology no less; without these principles, mere substitutes are offered in place of that evidence which alone suffices for true conviction. It can hardly be expressed how much assistance these ontological notions—which may be drawn from the present work—bring to one who is meditating or teaching; for this reason, I have been accustomed to call them by the name of guiding notions. For the rest, many things remain that could be added to these, but they must be deduced from what we have handed down here. Therefore, for those who make our teachings familiar to themselves, it will not be difficult to progress to further matters, once they have clearly perceived the laws of the scientific method scientific method original: methodi scientificæ; for Wolff, this meant the "demonstrative method," using clear definitions and syllogistic logic to move from known truths to new ones and have learned how to apply them in practice. Furthermore, the subsequent philosophical works will speak openly of the fertility of ontological principles, since the things to be demonstrated in those works are resolved into these same principles.

Marburg was the university city where Wolff lived and taught during his exile from Prussia (1723–1740) after his philosophical ideas were accused of leading to fatalism.