Not perception (perceptio), but conception (conceptio) alone gives science; that which we can “conceive” is true; the understanding as such cannot err, but undoubtedly the imagination can lead us to confuse the merely perceived with that which is conceived.  The method of science is geometrical demonstration, which starts from (genetic) definitions, and from their analysis obtains axioms, from their combination, theorems.  That which is thus proved a priori must, as already remarked, be confirmed a posteriori.  The highest of all sciences is natural philosophy, since it considers not sense-objects only, not (like mathematics) the objects of reason only, but the actual itself in its true character.  Hence it is the divine science, while the human sciences busy themselves only with our ideas or the relations of things to us.

%2.  Christian Wolff.%

Christian Wolff was born at Breslau in 1679, studied theology at Jena, and in addition mathematics and philosophy, habilitated at Leipsic in 1703, and obtained, through the instrumentality of Leibnitz, a professorship of mathematics at Halle, in 1706.  His lectures, which soon extended themselves over all philosophical disciplines, met with great success.  This popularity, as well as the rationalistic tendency of his thinking, aroused the disfavor of the pietists, Francke and Lange, who succeeded, in 1723, in securing from King Frederick William I. his removal from his chair and his expulsion from the kingdom.  Finding a refuge in Marburg, he was called back to Halle by Frederick the Great a short time after the latter’s ascension of the throne.  Here he taught and wrote zealously until his death in 1754.  In his lectures, as well as in half of his writings,[1] he followed the example of Thomasius in using the German language, which he prepared in a most praiseworthy manner for the expression of philosophical ideas and furnished with a large part of the technical terms current to-day.  Thus the terms Verhaeltniss (relation), Vorstellung (representation, idea), Bewusstsein (consciousness), stetig (continuus), come from Wolff, as well as the distinction between Kraft (power) and Vermoegen (faculty), and between Grund (ground) and Ursache (cause),[2] Another great service consisted in the reduction of the philosophy of Leibnitz to a systematic form, by which he secured a dissemination for it which otherwise it would scarcely have obtained.  But he did not possess sufficient originality to contribute anything remarkable of his own, and it showed little self-knowledge when he became indignant at the designation Leibnitzio-Wolffian philosophy, which was first used by his pupil, Bilfinger.  The alterations which he made in the doctrines of Leibnitz are far from being improvements, and the parts which he rejected are just the most characteristic and thoughtful of all.  Such at least is the opinion of thinkers