Why did Gottlob Frege criticize Edmund Husserl’s Philosophy of Arithmetic?

The German logician Gottlob Frege criticized Edmund Husserl’s Philosophie der Arithmetik (1891) primarily because he believed Husserl confused logical considerations with psychological ones.1

Frege charged Husserl with committing the error of psychologism—the view that the laws of logic and mathematics could be grounded in or derived from the study of mental processes and psychological acts. For Frege, who sought to establish a rigorous, objective foundation for mathematics through logic, this reliance on psychology was fundamentally misguided.12

This critique was highly significant for Husserl’s intellectual development. It prompted him to engage in a rigorous analysis and critical discussion of psychologism, eventually leading him to move away from his earlier psychological approach and toward the development of phenomenology, which sought to discover the essential structures of consciousness and meaning rather than merely describing psychological states.31