Roger Ariew

I discuss some of Leibniz's pronouncements about fringe phenomena__various monsters; talking dogs; genies and prophets; unicorns, glossopetrae, and other games of nature__in order to understand better Leibniz's views on science and the role these curiosities play in his plans for scientific academies and societies. However, given that Leibniz's sincerity has been called into question in twentieth-century secondary literature, I begin with a few historiographical remarks so as to situate these pronouncements within the Leibnizian corpus. What emerges is an image of Leibniz as a sober, cautious interpreter, a skeptic one might say, but one who is prepared to concede the possibility of many strange phenomena. Leibniz expects these fringe phenomena to take their place among the natural curiosities catalogued as part of a hoped for empirical database intended as means toward the perfection of the sciences.

I consider two events in late seventeenth-century philosophy: the condemnation of Cartesianism by the church, the throne, and the university and the noncondemnation of Gassendism by the same powers. What is striking about the two events is that both Cartesians and Gassendists accepted the same proposition deemed heretical. Thus, what was sufficient to condemn Cartesianism was not sufficient to condemn Gassendism. As a result, I suggest that to understand what is involved in condemnation one has to pay close attention to the intellectual and/or social context and to rhetorical strategy, not just to the propositions condemned. In this case, what is at stake are some of the central propositions of corpuscularianism and the mechanical philosophy.

Descartes' image of the tree of knowledge from the preface to the French edition of the Principles of Philosophy is usually taken to represent Descartes' break with the past and with the fragmentation of knowledge of the schools. But if Descartes' tree of knowledge is analyzed in its proper context, another interpretation emerges. A series of contrasts with other classifications of knowledge from the seventeenth and eighteenth centuries raises some puzzles: claims of originality and radical break from the past do not seem warranted. Further contrasts with Descartes' unpublished writings and with school doctrines lead to the ironic conclusion that, in the famous passage, Descartes is attempting to appeal to conventional wisdom and trying to avoid sounding novel.