IV. Strawson on the traditional logic

In his Introduction to Logical Theory, Strawson argues that Aristotelian logic can be given a successful interpretation into ordinary English, but not into the symbolism of Principia Mathematica, on the grounds that Aristotelian logic and ordinary English share something absent in PM, namely, the doctrine of presupposition. It is argued that Strawson is mistaken. PM does justice to the logical rules of Aristotelian logic and also has a fully articulated doctrine of presupposition.