Abstract

This paper explores Locke’s thinking specifically about syllogisms and more generally about logic and proper logical method. Locke’s texts display a mixed attitude toward syllogisms. On the one hand, he was highly critical of syllogisms and their central role in Scholastic disputation. On the other hand, he sometimes allowed that syllogisms could effectively capture valid forms of inference and could be useful in certain contexts. This paper seeks to explain Locke’s mixed attitude by showing that he believed syllogisms were useful in the context of explanation but not in the context of discovery. Syllogisms could help to formalize and evaluate arguments already constructed using informal psychologistic methods, but they would not help to generate new arguments or to make new discoveries. The second part of the paper examines substantial changes to the fourth edition of the Essay in which Locke expands his critical remarks on syllogisms and related topics. Evidence is presented that strongly suggests Locke made these changes to the Essay in response to works published by John Sergeant. This discovery is important because it indicates Locke’s willingness to consider the views of his adversaries and reformulate his own views accordingly.