The Logic of Dead Humans: Abelard and the transformation of the Porphyrian Tree

Interest in philosophical anthropology in the early twelfth century was limited to the logical question of how to think and speak about dead humans. This question was prompted by the logic of living and dead humans based on the doctrine of substance found in Aristotle’s Categories and in the division of substance, as outlined by Porphyry to exemplify the logic of genus and species relations in the Isagoge. Abelard held the view that there is no such thing as a dead human, and this provoked an intense response from his contemporaries. Abelard’s contemporaries, including Alberic of Paris and other anonymous authors, mounted a number of arguments against Abelard’s views. The stakes were high for them: as realists about species and genera, Abelard’s denial that there are dead humans threatened their entire interpretation of the structure of species and genera, and thereby their theory of universals.