Aristotelian Predicate Calculus Restored Pieter Seuren This is about a surprising thing I discovered recently with regard to predicate calculus. For the past 100 years, Aristotelian Predicate Calculus (APC) has been replaced by modern, Russellian predicate calculus, for valid reasons. However, the faults of APC are easily restored in a way that differs from Russell's and involves only minimal changes to the Aristotelian Square, something that was, apparently, never noticed before. This result is significant, especially in the context of natural language semantic intuitions. I will also show how the original Aristotelian Square is automatically restored to its pristine form if the standard negation is replaced with a more restricted negation that leaves presuppositions untouched.