UC Berkeley

It has been universally assumed that sensible qualities—colors, smells, shapes and sizes—must either be “out there” or “in here”: they must either be features of the external world or modifications of perceivers’ minds. Neither option is satisfying, because both force us to relinquish the striking intuition that there is something shared by a tomato and an after-image, a beach ball and a phosphene, when each is said to look red or to look round. The central insight of my dissertation is that the choice between sensible qualities being “out there” or “in here” is a false one: it stems from a misunderstanding of the metaphysics of sensible qualities. The mind and the material world play distinct roles in the instantiation of sensible qualities: material bodies are the bearers of sensible qualities; minds perceive these qualities. Each guarantees an instance of the quality, but does so in a way that does not exclude the other. These observations concerning the metaphysical nature of sensible qualities have expansive ramifications for the philosophy of mind; for at bottom, they reveal that the mind and the world play supportive, rather than antagonistic, roles in the constitution of conscious phenomenology.

In my dissertation, I develop a historically motivated account of two kinds of sensible instances. The redness of an ordinary tomato is a mind-independent sensible instance because inherence in the physical tomato is all that is required for this instance to exist. I trace this notion of inherence back to Locke, arguing that for him, inherence in a substance is what explains the instantiation of a sensible quality. But now consider an experience of a red after-image. We cannot describe the phenomenology of this experience by appeal to an uninstantiated universal; for this fails to capture how the redness that you experience is right there in front of you, not in Platonic heaven. So there must be an actual instance of redness present. But, unlike in the case of the tomato, there is no suitable object for redness to inhere in. There is no material body that is red; nor can the mind serve as the bearer of redness, for this would have the absurd implication that the mind, when perceiving, is itself literally red. Arguing that this is the real insight behind Berkeley’s famous maxim esse est percipi, I defend the view that such an instance of redness exists, not in virtue of having any bearer (contra Locke), but rather as the object of a perceiver’s awareness. Just as in the case of pains, the very fact that a perceiver enjoys an experience of a red after-image guarantees an instance of redness of which she is aware.

Thus, sensible qualities turn out to be an ontologically flexible kind—some instances inhere in material bodies, others are the objects of a perceiver’s mental states. More importantly, however, the two modes of instantiation are not exclusive of each other even in the case of a particular instance. Consider, for example, a case in which one perceives a ripe tomato: in this situation, two conditions obtain, each of which is sufficient for the instantiation of redness. First, there is a material object—the tomato—that redness inheres in. But second, the perceiver is in a mental state whose existence guarantees an instance of redness. In such a case, given that there is only one instance of redness present, it must be over-determined. A perceived instance of redness, then, simultaneously inheres in a physical object and is the object of a perceiver’s awareness.

I use this framework to develop a novel version of naïve realism—the view that ordinary perception is constitutively an awareness of the mind-independent world—which acknowledges the rich phenomenology of hallucinations. There has been unanimous agreement that this combination of features is impossible to secure. For given the absence of a physical object, if a hallucination makes the perceiver aware of redness, it must make the perceiver aware of a mind-dependent instance of redness. Many have argued, though, that if the hallucinated instance is mind-dependent, it seems as though the instance of redness in the veridical perception must be as well, thereby falsifying naïve realism.

First, I argue that representationalism—the view most commonly endorsed by those who accept the argument—is unable to do justice to the phenomenology of experience. But then, I go on to show that the argument is invalid, thereby defending naïve realism. I argue that both veridical and hallucinatory acts of awareness are individually sufficient for their items, but it is only the instances in the hallucination that are mind-dependent. For remember that the instance of redness in the veridical case is over-determined: despite the sufficiency of the perceiver’s state, the presence of a material body that is itself sufficient for the instance in question means that this instance can outlive the experience, continuing to inhere, now unperceived, in the tomato. This makes the items of veridical perception mind-independent. Nonetheless, veridical perception and hallucination have the same phenomenal character, because both comprise an awareness of the same sensible qualities. The contribution that particular instances of these qualities make to conscious phenomenology is unaffected by their ontological status—that is, by whether or not they are mind-independent. In paying close attention to the underlying metaphysics, then, we have established the world-involving nature of perception while nonetheless respecting the mind’s capacity to generate phenomenal character.