Crusius Christian August (1715–75), German philosopher, theologian, and a devout Lutheran pastor who believed that religion was endangered by the rationalist views especially of Wolff. He devoted his considerable philosophical powers to working out acute and often deep criticisms of Wolff and developing a comprehensive alternative to the Wolffian system. His main philosophical works were published in the 1740s. In his understanding of epistemology and logic Crusius broke with many of the assumptions that allowed Wolff to argue from how we think of things to how things are. For instance, Crusius tried to show that the necessity in causal connection is not the same as logical necessity. He rejected the Leibnizian view that this world is probably the best possible world, and he criticized the Wolffian view of freedom of the will as merely a concealed spiritual mechanism.
His ethics stressed our dependence on God and his commands, as did the natural law theory of Pufendorf, but he developed the view in some strikingly original ways. Rejecting voluntarism, Crusius held that God’s commands take the form of innate principles of the will (not the understanding). Everyone alike can know what they are, so (contra Wolff) there is no need for moral experts. And they carry their own motivational force with them, so there is no need for external sanctions. We have obligations of prudence to do what will forward our own ends; but true obligation, the obligation of virtue, arises only when we act simply to comply with God’s law, regardless of any ends of our own. In this distinction between two kinds of obligation, as in many of his other views, Crusius plainly anticipated much that Kant came to think. Kant when young read and admired his work, and it is mainly for this reason that Crusius is now remembered.
See also KANT, NATURAL LAW, PUFENDORF. J.B.S.