Intentionality

Intentionality is the property of the mind by which its mental states, such as perceptions, beliefs and desires, are directed at something: they are always about an object, whether external or internal.

The term comes from the Latin in-tendere, "to stretch toward." Reflection on the relation between thought and what is thought goes back to antiquity, but intentionality became a specific subject of study in modern philosophy, once consciousness came to occupy a privileged place in philosophical work. Before that, it was largely taken for granted that the subject has access to the world. Thomas Aquinas spoke of an "intentional being" of knowledge, in which the form of things is present in the mind without the mind becoming their matter.

Franz Brentano, in Psychology from an Empirical Standpoint (1874), presented it as the mark that distinguishes mental phenomena from physical ones: the former are directed at an object, the latter are not. Edmund Husserl made it the core of phenomenology, holding that every experience points toward an object. Jean-Paul Sartre went so far as to identify it with consciousness itself, while Martin Heidegger reframed it as a form of care or of being-in-the-world.

A central problem is intentional inexistence: if I think about Superman, who does not exist, what is my thought about? Three broad responses have been proposed: eliminativism, which denies that such states are possible; relationalism, which understands intentional states as relations to an object; and adverbialism, which understands them as ways of thinking or perceiving.

Current debate runs between naturalism, which aims to reduce intentional properties to properties studied by the natural sciences, and phenomenal intentionality theories, which ground intentionality in consciousness. The concept also returns in the philosophy of language and in artificial intelligence, where it is asked whether a system can have genuine intentionality or only manipulate symbols, as John Searle argued with his Chinese room thought experiment.