The name René Descartes will forever be entwined with our hopes and fears about the technological project. While it was Francis Bacon who originated the idea of conquering nature for the sake of relieving man’s estate, it was Descartes who told us we might truly become “like masters and possessors of nature”; Descartes who gave us the mathematical physics that has proven to be the indispensable instrument of modern science; and Descartes who foresaw that the ultimate instrument of the Baconian project would have to be medicine, since health is the primary good of life and the foundation of all other goods. The technological project was from the start biotechnological—in intent if not in realized practice—and it is hard not to think of today’s “transhumanists” when we read Descartes’ quasi-promise that technology might spare us even the “enfeeblement of old age.”

But the mastery and possession of nature is not the only, perhaps not even the deepest, theme of Descartes’ thought. We find in Descartes, and especially in his epoch-making Discourse on Method, a reflectiveness about what it means to be human and about the political conditions of his own activity that far outstrips the reflections we find in the contemporary heirs of his rhetoric, or indeed even what Descartes claims to learn from his own science. No mere scientist could have written the Discourse on Method or could help us understand the full depth of its complex message—and particularly its political and social message.