“Brentano stands to Husserl in very much the same relation in which, say Frege stands to Wittgenstein: one can no more hope to gain a sympathetic understanding of Wittgenstein’s presuppositions, preoccupations, and procedures in ignorance of his inheritance from Frege than one can hope to gain an understanding of Husserl’s in ignorance of his inheritance from Brentano. And in both the cases the reason is the same: neither Wittgenstein nor Husserl enjoyed a widely-based, formal education or training in philosophy; on the contrary, their respective philosophical outlooks were initially formulated in the context of, and in response to, an extremely narrow set of philosophical concerns—the concerns, predominantly, of a single philosopher. Husserl’s early philosophy is Brentanian through and through (though this is not of course to deny the influence of others on him—Bolzano, Lotze, Stumph, Kant, and Frege, amongst others).”
In the chapter, “Prolegomenon: Brentano’s Legacy,” Bell says that “at the most general level Husserl inherited from Brentano a vision of the nature, the goals, and the methods of philosophical enquiry; and more specifically he inherited from him doctrines concerning, for example, phenomena, intuitions, language, logic, science, truth, certainty, evidence, and analysis.”
Brentano was primarily a psychologist and his work was devoted to investigating the empirical laws which govern mental phenomena. However, most of his books are inclined more towards philosophy than empirical psychology. According to Bell, Husserl was introduced to the word “phenomenology” by Brentano:
“Although Husserl was undoubtedly influenced, and formatively, by Brentano’s so-called ‘psychology’, and although, more generally, Husserl was clearly excited by the revolutionary new ways of studying the human mind that were beginning to emerge at precisely the time he became interested in philosophy, it was not at all ‘empirical psychology’ which captured his imagination; rather he was fired by a distinctively philosophical discipline which Brentano liked to call ‘descriptive psychology’, or ‘psychognosy’, or, sometimes, “descriptive phenomenology’.
It is noteworthy that in the time of Brentano, phenomenology was primarily a discipline of empirical psychology—it was strictly focused on the study of mental and physical phenomena which means to the mental acts and their contents. It had very little to do with philosophy.