Brentano, Franz Clemens (1838–1917)

3. Intentionality

In the search for a positive criterion marking off mental from physical phenomena Brentano revived the Aristotelian-Thomistic conception of intentional inexistence in the Psychology. Every mental phenomenon is intentional, contains an object in itself, or no physical phenomenon does. In seeing something is seen, in judging something is accepted or rejected, in hoping something is hoped for and so on. Hence psychology cannot be reduced to or replaced by a physical science. Brentano maintained this demarcation principle but modified his conception of intentionality in a more epistemologically realist direction. A middle phase finds him rejecting the immanent conception of objects, accepting that the object of intentionality may be outside consciousness, and may be real, or an ens rationis, like a state of affairs, or even nonexistent. This middle view was most influential among his students.

Brentano’s student Twardowski went on to distinguish the mental acts themselves from their subjects, from their objects and their contents. Your seeing Jones would be, according to Twardowski’s account, a mental act that has you as its subject, Jones as its object and a visual image as its content. Every mental act then has an object, but not all such objects exist or are real. This view influenced Meinong’s theory of objects (see Meinong, A. §§2–4; Twardowski, K. §3).

However, Brentano himself later rejected all non-real and nonexistent objects (see §4 below). Since someone who judges (correctly) that unicorns do not exist seems to stand in a rejecting relation to something nonexistent, Brentano came to regard intentionality as not a relation but as merely relation-like, the similarity being that we think of relations in a similar way. In thinking of John touching Mary, we think directly of John and indirectly of Mary, but she too exists. In thinking of Mary rejecting unicorns we think directly of the unicorn-rejecting subject Mary and only indirectly of what she rejects. There are no non-real objects; they are fictions engendered by a careless use of language.

Brentano emphasizes that, in knowing that one is in a mental state, one knows directly and immediately that there is a certain individual thing – namely, the one who is in that state. And you, of course, are the one who is in your mental state. We may single out three different phases of this situation: (1) I can know that I hope for rain; (2) as a rational being, I can conceive what it is to hope for rain; and (3) that the only type of entity that can have the property of hoping for rain is an individual thing or substance.

Following Leibniz, Brentano distinguishes two types of certainty: the certainty we can have with respect to the existence of our conscious states, and the a priori certainty that may be directed upon axioms and other necessary truths. These two types may be combined in a significant way. At a given moment, I may be certain, on the basis of inner perception, that there is believing, desiring, hoping and fearing; and I may also be certain a priori that there cannot be believing, desiring, hoping and fearing unless there is a substance that believes, desires, hopes and fears. In such a case, it will be certain for me (Brentano says that I ‘perceive’) that there is a substance that believes, desires, hopes and fears. It is also axiomatic, Brentano says, that if one is certain that a given substance exists, then one is identical with that substance.