Franz Clemens Honoratus Hermann Brentano (January 16, 1838 Marienberg am Rhein (near Boppard) - March 17, 1917 Zürich) was an influential figure in both philosophy and psychology. His influence was felt by other figures such as Edmund Husserl and Alexius Meinong who followed and adapted Brentano's views.
Franz Brentano studied philosophy at the universities of Munich, Würzburg, Berlin (with Trendelenburg) and Münster. He had a special interest in Aristotle and scholastic philosophy. He wrote his dissertation in Tübingen On the manifold sense of Being in Aristotle.
Subsequently he began to study theology and entered the seminar in Munich and then Würzburg, preparing to become a Roman Catholic priest (ordained August 6, 1864). In 1865 - 1866 he writes and defends his habilitation essay and theses and begins to lecture at the university of Würzburg. His students in this period include among others Carl Stumpf and Anton Marty.
Between 1870 and 1873 Brentano is heavily involved in the debate on papal infallibility. As strong opponent of such a dogma, he eventually gives up his priesthood. Following his religious struggles, also Stumpf (who was studying at the seminar at the time) is drawn away from the church.
In 1874 he publishes his major work: "Psychology from an empirical standpoint" and from 1874 to 1895 he teaches at the university of Vienna. Among his students are Edmund Husserl, Alexius Meinong, Christian von Ehrenfels and many others (see School of Brentano for more details). While beginning his carreer as a full ordinary professor, he is forced to give up his Austrian citizenship and his professorship in 1880 to be able to marry. He is permitted to return to the university only as a Privatdozent.
After his retirement he moves to Florence in Italy and at the outbreak of the First World War he transfers to Zürich, where he dies in 1917.
Work and Thought
Brentano is best known for his reintroduction of the concept of intentionality—a concept derived from Scholastic philosophy—to contemporary philosophy in his lectures and in his work Psychologie vom Empirischen Standpunkte (Psychology from an Empirical Standpoint). While often simplistically summarised as "aboutness" or the relationship between mental acts and the external world, Brentano defined it as the main characteristic of psychical phenomena, by which they could be distinguished from physical phenomena. Every mental phenomenon, every psychological act has a content, is directed at an object (the intentional object). Every belief, desire etc. has an object that they are about: the believed, the wanted. Brentano used the expression "intentional inexistence" to indicate the status of the objects of thought in the mind. The property of being intentional, of having an intentional object, was the key feature to distinguish psychical phenomena and physical phenomena, because physical phenomena lack intentionality altogether.
Theory of Perception
He is also well known for claiming that Wahrnehmung ist Falschnehmung (literally 'truth-grasping is false-grasping') that is to say perception is erroneous. In fact he maintained that external, sensory perception could not tell us anything about the de facto existence of the perceived world, which could simply be illusion. However, we can be absolutely sure of our internal perception. When I hear a tone, I cannot be completely sure that there is a tone in the real world, but I am absolutely certain that I do hear. This awareness, of the fact that I hear, is called internal perception. External perception, sensory perception, can only yield hypotheses about the perceived world, but not truth. Hence he and many of his pupils (in particular Carl Stumpf and Edmund Husserl) thought that the natural sciences could only ever yield hypotheses and not universal, absolute truths as in pure logic or mathematics.
Albeit this may seem strange in view of the above, Brentano held the firm belief that the method of philosophy should be the method of the natural sciences.