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Thinkers

Franz Brentano

Phenomenological · Europe · 1838 to 1917

German-Austrian thinker who held that every mental act is directed at something, and that this marks the mind off from the physical.

What it is

Franz Brentano (1838 to 1917) was a German-Austrian philosopher and psychologist who is best known for bringing the idea of intentionality into modern philosophy. By intentionality he meant that every mental state is directed at something, whether a thing seen, a thought or a hope. He was born at Marienberg am Rhein and studied mathematics, philosophy and theology.

He began as a Catholic priest and left the priesthood in 1873. His book Psychology from an Empirical Standpoint (1874) is regarded as his main work. He was strongly influenced by Aristotle and the medieval Scholastics, and also by the empiricist and positivist movements of his century. The young Martin Heidegger was inspired by his early work on Aristotle.

The main ideas

  • Philosophy should be rigorous. He held that philosophy must be done in a scientific manner. At his thesis defence in 1866 he stated that the true method of philosophy is that of natural science.
  • Psychology as a science. He wanted a scientific psychology, which he defined as the science of mental phenomena, and argued that mental phenomena are the objects of inner perception while physical ones are known by outer perception.
  • Intentionality. Every mental phenomenon refers to a content or is directed toward an object. This idea, taken from medieval philosophy, became central to later philosophy of mind and to phenomenology.
  • One consciousness. We can have only one mental phenomenon at a time, and consciousness is also a unity across time, which is why we can hear a melody and not just a series of notes.
  • Three kinds of mental act. He sorted mental life into presentations, judgments, and love and hate, and tied logic, ethics and aesthetics to them as the true, the good and the beautiful.
  • Doubts about perception. He claimed that outer perception is "misconception", meaning that it cannot tell us how things really are.

What it looks like in practice

Try to think about nothing, and notice that every thought you have is a thought of something: a face, a worry, a tune. Brentano would say that this directedness is what marks the mental off from the physical, since a stone or a puddle is not about anything. This is an illustration of his line of questioning, not a passage from his writing.

Books and moments

  • Psychology from an Empirical Standpoint (1874) is his main work, setting out the study of mental phenomena and intentionality.
  • On the Several Senses of Being in Aristotle is an early work that inspired the young Martin Heidegger.

Questions and criticism

  • A hard word to pin down. His own wording of the intentionality thesis is, by common agreement, not wholly unambiguous.
  • Is the mental a separate class? If every mental state points at something, it is fair to ask how that applies to moods or feelings without a clear object.
  • Can perception be so unreliable? His claim that outer perception cannot be trusted raises the question of how science, which he admired, can rest on it.

Close neighbours

Aristotle and the medieval Scholastics are the thinkers he drew on most. The pages on Edmund Husserl, Martin Heidegger and Gottlob Frege show the phenomenological and logical traditions that took up or argued against his ideas.

Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.

Who they connect to

Influenced

  • Edmund Husserl · Husserl was his student in Vienna and took up his account of the directedness of mental acts.

Influenced by

  • Aristotle · He wrote his first book on Aristotle and took up his account of the soul.

Other Phenomenological thinkers

Sources we used

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