[Footnote 2:  Eucken, Geschichte der Terminologie^ pp. 133-134.]

Wolff reaches his division of the sciences by combining the two psychological antitheses—­the higher (rational) and lower (sensuous) faculties of cognition and appetition.  On the first is based the distinction between the rational and the empirical or historical method of treatment.  The latter concerns itself with the actual, the former with the possible and necessary, or the grounds of the actual; the one observes and describes, the other deduces.  The antithesis of cognition and appetition gives the basis for the division into theoretical and practical philosophy.  The former, called metaphysics, is divided into a general part, which treats of being in general whether it be of a corporeal or a spiritual nature, and three special parts, according to their principal subjects, the world, the soul, and God,—­hence into ontology, cosmology, psychology, and theology.  The science which establishes rules for action and regards man as an individual being, as a citizen, and as the head or member of a family, is divided (after Aristotle) into ethics, politics, and economics, which are preceded by practical philosophy in general, and by natural law.  The introduction to the two principal parts is furnished by formal logic.

Philosophy is the science of the possible, i.e., of that which contains no contradiction; it is science from concepts, its principle, the law of identity, its form, demonstration, and its instrument, analysis, which in the predicate explicates the determinations contained in the concept of the subject.  In order to confirm that which has been deduced from pure concepts by the facts of experience, psychologia rationalis is supplemented by psychologia empirica, rational cosmology by empirical physics, and speculative theology by an experimental doctrine of God (teleology).  Wolff gives no explanation how it comes about that the deliverances of the reason agree so beautifully with the facts of experience; in his naive, unquestioning belief in the infallibility of the reason he is a typical dogmatist.

A closer examination of the Wolffian philosophy seems unnecessary, since its most essential portions have already been discussed under Leibnitz and since it will be necessary to recur to certain points in our chapter on Kant.  Therefore, referring the reader to the detailed accounts in Erdmann and Zeller, we shall only note that Wolff’s ethics opposes the principle of perfection to the English principle of happiness (that is good which perfects man’s condition, and this is life in conformity with nature or reason, with which happiness is necessarily connected); that he makes the will determined by the understanding, and assigns ignorance as the cause of sin; that his philosophy of religion, which argues for a natural religion in addition to revealed religion (experiential and rational proofs for the existence of God, and a deduction of his attributes), and sets up certain tests for the genuineness of revelation, favors a rationalism which was flexible enough to allow his pupils either to take part in orthodox movements or to advance to a deism hostile to the Church.