The Third Analytic of Men is a work by Ajencis, regarded by many to be his magnum opus. The Third Analytic interrogates the aspects of human nature that make knowledge possible, as well as the human weaknesses that make knowledge so difficult to attain. As Ajencis notes, "if all Men disagree on all matters, then most Men confuse deception for truth". He investigates the reasons, not only for deception in general, but for the erroneous sense of conviction that sustains it, giving what has come to be called the "selfish knower" thesis, the idea that convenience, conditioning, and appeal (as opposed to evidence and rational argumentation) are the primary motivation for the beliefs of the vast majority.