Brentano, Franz Clemens (1838–1917)

4. Types of being: substance, accident and boundary

In Brentano’s earlier writings he assumed that in addition to concrete individual things or entia realia, there are also ‘non-things’ or entia irrealia, falling into several different categories. They include: (1) ‘intentionally inexistent’ objects, such as that devil that is supposed to ‘exist in mind’ when one thinks about a devil; (2) those objects, often called ‘propositions’, thought to be designated by ‘that’-clauses or sentential gerundives (as in ‘that there are living beings on Venus’, or ‘there being living things on Venus’); (3) properties or universals, such as redness and being-both-round-and-square; and (4) states and events.

Brentano’s rejection of such ‘non-things’ was based upon two general principles. First, the only objects that we can think about, strictly speaking, are concrete individual things. We do think of concrete things; ‘think of’ is univocal; therefore whatever we think of is a concrete thing. ‘Concrete’ does not here imply materiality. God and the soul, according to Brentano, are concrete but non-material. Second, an adequate understanding of language will show us that any plausible statement that ostensibly refers to such non-things may be construed as pertaining only to concrete things. Brentano defends the second principle with considerable ingenuity.

The theory of ‘concrete predication’ tells us that all of our thoughts may be adequately expressed by using concrete terms in place of predicates. We may best understand this theory if we imagine that all predicates in our language have been replaced by terms, and consider a view of the world which might naturally suggest itself to us if our language were in fact of such a sort, as it very well could have been. ‘Concrete predication’ may recall what Aristotle had said of simple judgments: ‘An “affirmation” is a statement affirming something of something; a “negation” is a statement denying something of something’. In simple affirmative judgments, Aristotle said, we combine things; and in simple negative judgments we separate them. Since such statements as ‘Mary is thinking’ are for us a natural way of describing people, one might suppose that, when a person is thinking, they stand in a certain relation to the property of thinking. But if we say ‘Some persons are thinkers’ (Brentano uses ‘ein Denkendes’, which one might translate more literally as ‘a thinking-thing’) then it may be more natural to suppose that we are describing not a relation between an individual thing and a property, but a relation between those individual things that are persons and those individual things that are thinkers. What, then, is the relevant relation between persons and thinkers?

Brentano uses Aristotle’s term and says that the thinker is an ‘accident’ of its subject. Aristotle had said, however, that accidents are ‘in’ their subjects. Brentano saw that there was a reason for reversing this, claiming that accidents contain their subjects. The relation of substance to accident is similar in fundamental respects to that of part to whole. Brentano tells us what may seem surprising at first, that a substance is a part of its accidents. An accidental determination of a substance is a larger whole which is not necessary to its substance. If I happen to be thinking at the moment, I am a substance which, for now, is a thinker. The thinker is, at the moment, an accident of that substance which is identical with me. An accident is something containing its substance but not necessary to the substance.

A substance is necessary to its accidents. The accidents could not exist unless the subject exists – just as, according to the principle of ‘mereological essentialism’, every whole is ontologically dependent upon its parts. But no accident is necessary to its subject; hence the use of the word ‘accident’. The expression ‘X is an accident of Y’ does not then introduce any unfamiliar concept into ontology, but refers only to a more generalized version of the part–whole concept.

In addition to distinguishing those individuals that are accidents from those that are substances, Brentano points out that there are individuals of still another sort. These include the points, lines and surfaces that constitute the inner and outer ‘boundaries’ of spatial objects. Boundaries exhibit a unique type of ontological dependence. Every boundary is necessarily such that it is a boundary of some constituent of the thing of which it is a boundary; but this is not to say that, for any thing of which it is a boundary, the boundary is necessarily such that it is a constituent of it. The point is of fundamental importance to ontology and the theory of categories, and may be put more precisely. Every boundary x is necessarily such that it is a boundary of (and therefore a constituent of) some constituent y of the entity z of which it happens to be a boundary. But from this fact, it does not follow that there is a constituent w of z which is such that x is necessarily a constituent of w. For example, a spatial point P is necessarily such that it is a constituent of a constituent C of the line L of which P happens to be a constituent. But, for any constituent C of L that you might mention, P need not be a constituent of C; some smaller constituent of C would do just as well. Analogously, this holds for the relation of lines to surfaces and for the relation of surfaces to three-dimensional bodies.

By contemplating the concept of a boundary in this way, Brentano claimed, we acquire the concept of infinite divisibility by means of which we can then understand what it is for an entity to be ‘continuous’. The general problem of the continuum occupied Brentano throughout his philosophical career.