On Monday, I gave a general overview of the main ideas in my forthcoming book The Unity of Perception: Content, Consciousness, Evidence. The key idea developed in the book is that perception is constituted by employing perceptual capacities—for example the capacity to discriminate and single out instances of red from instances of blue. Perceptual content, consciousness, and evidence are each analyzed in terms of this basic property of perception. In this way, the book provides a unified account of perceptual content, perceptual consciousness, and perceptual evidence. What unifies the account are perceptual capacities. Due to the grounding role of perceptual capacities, I call the view capacitism. On Tuesday, I developed the foundations of the book: the general and particular elements that constitute perceptual states. Yesterday, I presented the view of singular perceptual content which the book puts forward. Today, I will focus on perceptual consciousness.

Part III of my book exploits the thesis that perception is constitutively a matter of employing perceptual capacities to address the problem of consciousness.[1] Orthodox views analyze consciousness in terms of sensory awareness of some entities. Such views differ widely on how they understand the nature of those entities. On one cluster of views, they are understood to be strange particulars, such as sense-data, qualia, or intentional objects. On a different cluster of views, they are understood to be abstract entities, such as properties. On a third cluster of views, they are mind-independent particulars in our environment, such as objects, property-instances, and events. What these views have in common is that they all analyze perceptual consciousness in terms of sensory awareness of some entities.

There are problems with all three versions of the orthodox view. In a nutshell, the problem with sense-data and qualia theories is the following: if the goal is to explain consciousness, it is unclear what the explanatory gain is of appealing to awareness of obscure entities, such as sense-data and qualia. On the face of it no explanatory progress has been made. In a nutshell, the problem with explaining consciousness in terms of sensory awareness of abstract entities is that abstract entities are not spatio-temporally located and not causally effective. It is unclear what it would be to be sensorily aware of such entities. In a nutshell, the problem with naïve realist views on which consciousness is analyzed in terms of awareness of mind-independent particulars is that such views leave mysterious how we could be conscious when we are hallucinating rather than perceiving.

Chapter 6 of my book breaks with this orthodoxy. It argues that perceptual consciousness is constituted by a mental activity, namely the mental activity of employing perceptual capacities. I call this view mental activism. Mental activism avoids the problems of the orthodox view of analyzing consciousness in terms of sensory awareness of some entity. Insofar as employing perceptual capacities constitutes representational content, mental activism is a form of representationalism. Standard representationalist views purport to explain perceptual consciousness in terms of a relationship—identity, grounding, supervenience—between perceptual consciousness and perceptual content. But they fail to explain in virtue of what this relationship holds. Some representationalist views have it that phenomenal character is identical to perceptual content (Tye 1995). Such an identity claim would amount to category mistake. More careful views have it that consciousness supervenes on or is grounded in representational content. However, these more careful views say almost nothing unless an explanation is given of what it is about representational content such that it grounds consciousness. Mental activism shows how employing perceptual capacities yields both consciousness and representational content. So what grounds consciousness in representational content is the fact that both stem from employing capacities. Thus, the view explains how and why consciousness is grounded in representational content.

The Argument for Mental Activism

I. If a subject S perceives a particular a, then S is employing a perceptual capacity C_α by means of which she discriminates and singles out a.

II. If S is employing C_α by means of which she discriminates and singles out a, then S’s phenomenal character is constituted by employing C_α by means of which she discriminates and singles out a.

From I-II.          If S perceives a, then S’s phenomenal character is constituted by employing perceptual capacity C_α by means of which she discriminates and singles out a.

III. If S suffers an illusion or a hallucination as of a, then S’s phenomenal character is constituted by employing C_α by means of which she purports to discriminate and single out a.

IV. If S perceives a or suffers an illusion or a hallucination as of a, then S’s phenomenal character is constituted by employing C_α, by means of which she (purports to) discriminates and singles out a.

V. Employing a perceptual capacity is a mental activity.

VI. If S perceives a or suffers an illusion or a hallucination as of a, then S’s phenomenal character is constituted by a mental activity.

From I-VI. Phenomenal character is constituted by a mental activity.

 

Mental activism posits a common element between perception, hallucination, and illusion at the level of employing perceptual capacities. However, at the level of the function of perceptual capacities, there is a primacy of the employment of capacities in perception over their employment in hallucination or illusion. In virtue of this primacy, mental activism is an externalist view of perceptual consciousness. So while at the level of employing perceptual capacities, perception, hallucination, and illusion are on a par, at the level of the function of perceptual capacities there is a primacy of perception over hallucination and illusion.

While standard views analyze perceptual consciousness in terms of awareness relations to peculiar entities, mental activism allows acknowledging that a hallucinating subject does not stand in a sensory awareness relation to anything despite being in a phenomenal state that purports to be of mind-independent particulars.

For a subject to be sensorily aware of a particular implies that the subject stands in a sensory awareness relation to that very particular. So a subject cannot be sensorily aware of the particular α without standing in a sensory awareness relation to α. Indeed, being sensorily aware of α entails the existence of α. In this sense, sensory awareness is factive.

If we recognize that perceptual consciousness need not be analyzed in terms of that of which we are sensorily aware, we can circumvent any commitment to both naïve realism and the peculiar entity view. Consider a subject who is in a phenomenal state, that is, an experiential state that is characterized by perceptual consciousness. We can all agree that for a subject to be in a phenomenal perceptual state is for her to be in an experiential state that purports to be of something. So far there is no reason to say that she is sensorily aware of something. After all, for a phenomenal state to purport to be of α does not imply that the subject is aware of α (or of anything else). Indeed, being in a phenomenal state does not entail the existence of that of which the mental state purports to be of. Moreover, being in a phenomenal state does not entail the existence of some other entity to which the subject stands in a sensory awareness relation. It follows that a subject can be in a phenomenal state without standing in a sensory awareness relation to any entity. So there is a structural difference between awareness of, on the one hand, and being in a phenomenal state, on the other. While awareness of is extensional, being in a phenomenal state is intensional.

As I argue in the book, there is no need to think that employing perceptual capacities entails the existence of the particulars that the perceptual capacities purport to single out. So mental activism allows that we can be in a mental state that is characterized by perceptual consciousness without being sensorily aware of any external, mind-independent particulars. A subject who is suffering a hallucination or an illusion as of what seems to her to be a mind-independent particular α employs a perceptual capacity that functions to single out mind-independent particulars under which α falls. Employing such a perceptual capacity accounts for the fact that it seems to the subject that α is present and accounts for her being intentionally directed at what seems to be an external, mind-independent particular without in fact being sensorily aware of α. Thus, mental activism avoids analyzing perceptual consciousness as constituted by (sensory awareness relations to) peculiar entities—be they phenomenal properties, external mind-independent properties, propositions, sense-data, qualia, or intentional objects. In avoiding analyzing perceptual consciousness as constituted by sensory awareness relations to peculiar entities, mental activism avoids the problems of orthodox common factor views.

So mental activism reconciles the following four theses. First, the view does not require positing that hallucinating or perceiving subjects stand in a sensory awareness relation to peculiar entities. In this respect, the view is ontologically more minimalist than any view that must appeal to such entities and thus upholds Quinean commitments to ontological minimalism. Second, the view satisfies the Aristotelian principle according to which the existence of any type depends on its tokens that in turn depend on concrete entities of the physical world. In this respect, the view is at an advantage over any view that must assume a Platonic ‘two realms’-view. Third, the view gives a positive account of the phenomenal character of hallucinations and, in this respect, is an improvement over naïve realism or austere relationalism. Finally, the view analyzes perceptual consciousness, in terms of employing perceptual capacities, where perceptual capacities are in turn individuated by the mind-independent particulars they function to single out. Thereby, mental activism amounts to a naturalized view of perceptual consciousness.

[1] Part III is based on material that is published in my paper “Perceptual Consciousness as a Mental Activity”, Noûs (2018).