Like Tschirnhausen and Thomasius, Wolff wrote a great part of his works in his mother tongue, while Leibnitz for the most part wrote only in Latin or French. This is an important matter, for, as we have already noticed (pp. 114 and 150), it is only when a nation possesses a science in its own language that it can really be said to belong to it; and in Philosophy most of all this is requisite. For thought has in it this very moment of pertaining to self-consciousness or of being absolutely its own; when one’s own language is the vehicle of expression, as when we talk of “Bestimmtheit” instead of “Determination,” and “Wesen” instead of “Essenz,” it is immediately present to our consciousness that the conceptions are absolutely its own; it has to deal with these at all times, and they are in no way foreign to it. The Latin language has a phraseology, a definite sphere and range of conception; it is at once taken for granted that when men write in Latin they are at liberty to be dull; it is impossible to read or write what men permit themselves to say in Latin. The titles of Wolff’s philosophic works are perpetually of this nature: “Rational thoughts on the powers of the human understanding and their right uses in the knowledge of the truth,” Halle, 1712, 8vo; “Rational thoughts on God, the world, and the soul of man, likewise on all things generally,” Frankfort and Leipzig, 1719; “On the action and conduct of men,” Halle, 1720; “On Social Life,” Halle, 1720; “On the operations of Nature,” Halle, 1723, and so on. Wolff wrote German and Latin quartos on every department of Philosophy, even on economics—twenty-three thick volumes of Latin, or about forty quartos altogether. His mathematical works make a good many more quartos. He brought into general use the differential and integral calculus of Leibnitz.