Christian Wolff and the Science of All Possible Things

What makes philosophy a science? According to the received interpretation, Christian Wolff considers the scientific method alone to be the key to rendering philosophical knowledge scientific. By contrast, this paper argues that the scientific character of Wolffian philosophy also depends on its object, namely on its being “the science of all possible things”. By comparing and analyzing the various formulations in which Wolff, between 1709 and 1728, proposed this famous definition of philosophy, the paper shows how the different meaning Wolff ascribed over time to the modal concept of “possible” has eventually obscured the original sense of that very definition. Thus, Wolff’s idea of philosophy as the science of possible things turns out to be rooted in the causal conception of modalities that belonged to Wolff before his adoption of Leibniz’s logical modalities. According to Wolff, philosophy is a science not only because it proceeds by demonstrations, but also because it explains the possibility (or producibility) of effects from their possible causes.