In Prolegomena to Pure Logic, Husserl criticizes logical psychologism. This criticism would point to the achievement of a pure logic. However, after that first reading, there is an authentic discussion about the problem of truth, which would be misunderstood by psychologism. Indeed, psychologism holds that truth is an integral part of the subject. Husserl, on the other hand, argues that truth is an idea and, as such, absolutely independent of the subject who thinks. Starting from a review of Prolegomena, the paper analyzes, first, the critique of psychologism; second, it compares the notions of truth in dispute; and, third, he concludes that the Prolegomena serve as an introduction to the theory of truth that develops in Husserl's early phenomenology.