Theoretical Difficulties for the Theory of Intentionality and Brentano's Problem

Brentano's ultimate problem is

Much of the contemporary history of the philosphy of mind has been various attempts to solve Brentano's problem. The fact that since Brentano's time we have discovered ways to make machines "think" has made many believe that the ultimate solution lies in understanding how computational manipulations of environmental information by the human brain can be performed according to physical laws alone.

The relation of mental functions to physical activities of the brain, however, is only part of Brentano's Problem. Brentano linked the concept of mental phenomena to intentionality. Brentano's problem is sometimes phrased as "how do explain intentionality in purely physical terms?" If we succeed in this, then (some claim) physicalism is true. Proving that some form of physicalism is true, is the holy grail of many contemporary philosophers. We need to bear in mind, then, that the complete statement of Brentano's Problem problem requires and understanding of

Intentionality, in turn, requires us to understand

The following brief discussion introduces these topics.

The Object Theory and the The Content Theory

There are two general theories of intentionality: the object theory and the content theory. Both have a certain measure of attractiveness -- and both have problems that (as far as I know) remain unsolved. In practice, the theories are not entirely separate, but it is useful to make an initial formulation as if they were.

The Object Theory

The example of the imagining a centaur is famous in the history of philosophy. The object theory, and the difficulities surrounding it, derive from philosophical reflection on this and similar examples of the use of our imagination.

Certainly, in one sense, there exists an object in our imagination; the object must be "real" or we would not be able to imagine it. There is a picture of something in my mind.

On the other hand, the centaur is known to be a mythical being and hence has no existence. Is my thought, then, actually directed toward a non-existing object? How can this be if an intentional act requires an object? Surely, the object toward which my thought is directed exists, otherwise, if the object theory is correct, there would be no thought at all.

Surely, we do not mean to imply that just because we imagine a centaur, that we bring into existence and actual centaur. I may inwardly "see" a centaur perfectly clealy, but that does not bring an actual centaur into existence in external reality. In what sense, then, are we to say that the imagined centaur is "real"? In what sense is it "an object"? If we insist (as is our first impulse) that those "objects toward which my thought is directed exist as a matter of certainty, is it not equally certain that some of those (mental) objects have corresponding objects in reality and others do not? Should we then say that all thoughts, whether they are directed toward imaginary or externally existing objects are all equally "valid" or "real"? This would seem to create great difficulties for the notion of truth; some of our thoughts must be true of the world (have objects in the real world corresponding to them) while others must not be. How can we differentiate those intentional acts which have corresponding objects in reality (e.g. in the case of perception, true memories) from those that involve imaginary objects or the products of hallucinations? The difficulties in answering these questions have caused many philosophers to conclude that the object theory of intentionality is hopelessly flawed.

The Content Theory

The content theory seeks to resolve some of the difficulties of the object theory. It utilizes the idea that there must be an intermediary between consciousness and its ultimate object. For a first approximation, this intermediary can be variously called a "sign," a "representation," a "vehicle" or, more generically, a "content" in the intentional act. Thus, the act of thinking of imagining an actually existing thing (say, a table) is easily described and explained: my image of the table is the vehicle, while the object of my intention is the table itself. To solve the problem of non-existing beings that can be the objects of thought, the content theory allows that content can exist or "be" without the corresponding object. In imagining a centaur, I have a mental image whose content is a centaur. The centaur "exists" as content in my mind, but there is no object outside of the mind corresponding to this thought.

Although some philosophers have accepted this as a "solution" to the problem of non-referring mental objects, it does not (in the view of other philosophers) adequately explain the genesis of meaning. How can mental representations (particularly images) obtain the meaning or content the appear to have? Surely, imagining a centaur is an act that can have meaning or content, but if there is no corresponding object to this content (either in the mind or in reality), how does this content come to have meaning? If we were to answer this question by saying "by virtue of the fact that the mind is directed toward a mental object to which it assigns meaning," we are thrown back to the obect theory of intentionality.

Thus, it seems, in my view, that both the object and the content theories are incomplete. Part of the reason for this, again in my view, is that many commentators have misunderstood Brentano's original formulation of problem of intentionality. In their misinterpretation of Brentano, they have broken apart (into subject and object) what Brentano understood as a single act. Furthermore, Brentano's problem does not involve (directly) our ability to imagine objects, such as a Centaur, that have no existence in the real world. The discussion below clarifies these points.

Brentano's Problem

In a famous passage, Brentano attempts to define mental phenomena in terms of intentionality:

Every mental phenomenon is characterized by what the Scholastics of the Middle Ages called the intentional (or mental) inexistence of an object, and what we might call, though not wholly unambiguously, reference to a content, direction toward an object (which is not to be understood here as meaning a thing), or immanent objectivity. (Brentano, 1874/1978, p. 88)

This passage has often been misinterpreted. The word "inexistence" in this context does not refer to the ability of the mind to conceive of objects that do not exist. That is a capacity of the mind, but not the definition of the mental, and not the topic Brentano is addressing here. The capacity in question is, as Brentano states, reference to a content or direction toward an object. The "in" of "inexistence" means that the presentation is in the mind; presentations capable of reference to non-present objects only exist in the mind.

Some philosophers regard images as non-intentional because they (or, more precisely, their raw appearances) have no intrinsic content. It is clear, however, that this describes mental images as if they existed apart from the lived-through experiences of the subject -- as if they were public images (percepts), rather than mental images. Public images have "content" (when a subject interprets them) in two senses: (1) the visual content, or the visible features that one may notice, inspect, or be aware of, and (2) the intentional content, or the content derived from what the image is understood to be an image of. To attend to (1) misses the point of what it is to be an image. We do not inspect the properties of the ink to determine what the sketch of Clinton is to connote. "Clinton," not "this sketch," is the intentional content of the image. The same is true of mental images; they have both visual and intentional content. It is, of course, possible to conceptually or theoretically strip away the consciousness of the raw appearances of mental images but (with a few exceptions) that is not the way we experience them. They have an intentional depth or content they are directed toward that is not actually separable from their being.

The meaning of introspecting mental objects needs to be clarified, since imagists have been accused of holding the characteristics of mental images to be given infallibly through introspection. Brentano, while he insisted on the general validity of inner consciousness as a form of understanding, did not even think introspection was possible. Introspection in the sense of inner observation (beobachtung) is not possible, because there are no separate inner objects that retain their properties independent of the acts of the subject. Brentano, like Wundt, insisted that we could not directly observe inner "objects" because the act of having an object was inseparable from the subject's attitude toward it. The only valid sense of introspection was "inner perception" (from wahrnemung, containing the roots for "true" and "to take"). I understand introspection to be absolutely certain only in the tautologous sense implied by Brentano's distinction: when we have a presentation, the only thing certain is that we have it. Everything else about it -- its causal history, and sometimes even its type - is subject to occasional error. The "properties" one does claim for images, then, belong not to objects per se, but are ways of characterizing our experiences and their general presumed causes and purposes.

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