Rene Descartes (1596-1650) and John Poinsot (1589-1644) were contemporaries who stood, unbeknownst to themselves, at a crossroads in the history of philosophy. While Poinsot's work on semiotics became unfashionable after his death, Descartes' theory of ideas carried modern philosophy down a different path that proved to be a dead end. In "Descartes & Poinsot", John Deely contends that semiotics can lead us beyond the rationalist trap of modernity. This innovative volume reveals that Poinsot's forgotten philosophies provide the missing link between the ancient and the postmodern.