“Of great importance is Brentano’s classification of psychic phenomena. There are three classes: presentations, judgments, and emotive acts. Of the first Brentano claims that all psychic phenomena are either presentations or involve presentations (a statement accepted by Husserl in an interpretation of presentations as “objectivating acts”). Judgments are conceived by Brentano as acts of affirmation or negation; thus he rejects a propositional theory of judgment. The third class (Akte der Gemütsbewegung) contains acts of volition as well as emotions, feelings, etc. These acts are conceived in analogy to judgments; they are either positive or negative (love vs. hate) and they are correct or incorrect (love is correct if its object is intrinsically worthy of being loved). This led Brentano to a conception of ETHICS as a discipline parallel to LOGIC. His basic ideas in ethics were first published as a paper he delivered in Vienna in 1889 ( Vom Ursprung sittlicher Erkenntnis; an English translation, Our Knowledge of Right and Wrong, already appeared in 1902). His ethics had a strong influence on Max Scheler and on G. E. Moore (1873-1958). In his later writings Brentano became more and more interested in developing his own ontology and theory of categories. He developed a position called “reism” according to which the basic category is that of res, which comprehends both concrete things and immaterial souls. This strict objectivistic attitude was initially not influential within the phenomenological movement, but it did become important for logic and ontology in Poland. In recent years these ideas have had great influence on philosophers such as Roderick Chisholm and Barry Smith.
Of great influence on Husserl was Brentano’s theory of wholes and parts, which he introduced in his “ontology,” the second part of his Würzburg lectures (in the 1870s Brentano inserted a descriptive part that he called “phenomenology” between the abovementioned “transcendental philosophy” and the “ontology”). Ontology has as its basic distinction that between collectiva and divisiva, which dichotomy is in turn classified as physical, logical, and metaphysical. The influence on Husserl’s formal and material ontology as developed in the third of his Logische Untersuchungen (1900-1901) is obvious, and it is likely that Husserl knew about these lectures via Stumpf, to whom he refers in this context and who had an extensive copy of these lectures.
The concept of Intentionality is only a problematic link between Brentano and phenomenology. This is already indicated by the fact that Brentano later gave up the term “intentional” because he thought that his views in this connection had been misunderstood. As a matter of fact Brentano does not talk about intention or intentionality, but rather uses expressions like “intentional inexistence” or “intentionally contain” that he introduced in order to distinguish psychic phenomena from physical phenomena. An isolated quality such as red is a physical phenomenon; red as belonging to consciousness is on the other hand a psychic phenomenon.
Intentional inexistence can be regarded as a mereological concept on two different levels. On the descriptive level, a psychic phenomenon is part of a complex consciousness to which belong, for instance, inner perception, acts of judgment, and emotive acts; on the metaphysical level, which also embraces entities that are not immediately given but inferred, it is conceived as part of a soul. In contexts like “intentional inexistence,” the term “intentional” does not determine the related expression “inexistence” (or “containment”) but modifies it, i.e., it changes its original meaning. If these words were used in this original meaning, the following conclusions would be valid: if something exists in something else, then both things exist; if something is contained in something other than it, there is a spatial relation between them. In the modified context of “intentional inexistence” and “intentional containment,” however, both conclusions are invalid. The intentional relation is thus, as Brentano explains in later writings, only “something relation-like” (etwas Relativliches). It is not, as in Husserl’s intentional acts, a matter of directedness toward an object transcendent to consciousness but, in contrast, something immanent to consciousness.”
From: Dieter Münch, “Franz Brentano” in: Lester Embree et alii (eds.), Encyclopedia of Phenomenology – Dordrecht: Kluwer, 1997, pp. 74-75.