Christian August Crisius, a German theologian and philosopher, born at Leuna, near Merse-burg, Jan. 10, 1715, died in Leipsic, Oct. 18, 1775. He was educated at Leipsic, where he was professor of theology at the time of his death. He was among the principal opponents of the reigning philosophy of Leibnitz and Wolf, which he challenged at once in the name of reason and faith, asserting its incompatibility with Christian dogmas; and he sought to establish a new philosophical scheme which should be perfectly orthodox. Philosophy is in his view the whole body of rational truths, whose objects are eternal, and is divided into logic, metaphysics, and disciplinary or practical philosophy. He subordinated the scholastic principle of contradiction to that of conceptibility (Gedenkbarkeit), founded logic upon psychology, attributed to the soul fundamental faculties and a liberty almost as complete as that of the Deity, and made the certainty of human knowledge consist in an inward constraint and inclination of the understanding, the guarantee of the truthfulness of which exists in the divine veracity.

The most important of his publications are: Entwurf der nothwendigen Ver-nunftwahrheiten (Leipsic, 1745); Logik, oder Weg zur Gewissheit und Zuverlassigkeit der menschlichen Erlcenntniss (1747); and Anlei-tung uber naturliche Begebenheiten ordentlich und vorsichtig zu denhen (1774).