Perceptual Content

It is Monday morning and I am riding the train through the post-industrial wasteland of northern New Jersey. I gaze out of the window and, suddenly, I see a deer. Let’s call it Frederik. The next morning, I am again on the train, riding through northern New Jersey. And, again, I see a deer. Let’s call it Ferdinand. It is the same time of day. Everything looks exactly the same on Tuesday as it did on Monday—including the deer. However, unbeknownst to me, the deer I see on Tuesday is not the same as the one I saw on Monday. So I am seeing different particulars.

As the particularity argument established, my perceptual state on Monday is constituted by Frederik, while my perceptual state on Tuesday is constituted by Ferdinand. There are many open questions. Assuming perceptual particularity is accounted for in terms of singular perceptual content, what is the nature of this singular perceptual content? When we suffer a non-veridical hallucination as of an object, then it seems to us that there is a particular object present, where in fact there is no such object. If veridical perceptual states have singular content, what is the content of a hallucination? Since in hallucination, we are not perceptually related to the particulars we seem to see, a hallucination cannot have singular content. What content, then, does a hallucination have? Finally, what accounts for the phenomenal character of hallucination, whereby it seems to us that a particular is present when no such particular is actually before us?

These questions can be put into focus by articulating two desiderata for any account of perception. One desideratum is to explain perceptual particularity, that is, to explain in virtue of what a perceptual state is constituted by the perceived particular. Let’s call this the particularity desideratum. The other desideratum is to explain what accounts for the possibility that perceptions of qualitatively identical yet numerically distinct particulars could have the same phenomenal character. Let’s call this the phenomenal sameness desideratum. More generally, the phenomenal sameness desideratum is to explain what accounts for the possibility that perceptions, hallucinations, illusions of distinct environments could have the same phenomenal character.

Chapter 3 argues that perceptual particularity is best accounted for in terms of perceptual content rather than in terms of epistemic, psychologistic, or ontological dependency properties. The argument goes as follows:

 

The Singular Content Argument

I. If a subject S perceives a particular a, then S discriminates and singles out a.

II. If S discriminates and singles out a, then S’s perceptual state M brought about by being perceptually related to a is constituted by discriminating and singling out a.

III. If M is constituted by discriminating and singling out a, then S represents a (under a mode of presentation) such that M has the property that its content is constituted by a.

From I-III. If S perceives a, then S’s perceptual state M brought about by being perceptually related to a has the property that its content is constituted by a.

 

Chapter 4 develops Fregean particularism, thereby providing the details of my account of singular perceptual content. Fregean particularism advances a new understanding of singular modes of presentation: the representational content of perceptual states is constituted by the perceptual capacities employed and the particulars (if any) thereby singled out. These modes of presentation can be individuated at the level of content types and token contents. Perceptions, hallucinations, and illusions with the same phenomenal character are constituted by employing the same perceptual capacities; they thereby share a content type. But the token content of perception, hallucination, and illusion differs at least in part. If one perceives a particular, one employs perceptual capacities that successfully single out that particular. Thereby, the token content is constituted by the particular singled out and thus is singular content. So perceptual particularity is accounted for. If one fails to single out a particular (perhaps because one is suffering an illusion or hallucination), the token content is gappy.

By showing how these aspects of perceptual experience can be integrated in terms of the perceptual capacities employed, Fregean particularism offers a non-disjunctivist account of perceptual content that synthesizes relationalist and representationalist insights. The history of philosophy is a history of false dichotomies. The dichotomy between relationalists and representationalists is one such false dichotomy. Relationalists argue that perceptual experience is constitutively a matter of a perceiver being related to her environment. Representationalists argue that perceptual experience is constitutively a matter of a perceiver representing her environment. However, the standard views in the debate are either austerely relationalist or austerely representationalist. According to austere representationalists, perception is constitutively representational but not constitutively relational (Dretske 1995, Tye 1995, Lycan 1996). According to austere relationalists, perception is constitutively relational but not constitutively representational (Campbell 2002, Martin 2003, Travis 2004, Brewer 2006). Fregean particularism avoids the pitfalls of both austere views by showing that perceptual relations to the environment and the content of experiential states are mutually dependent in any explanation of what brings about perceptual awareness of the environment. With relationalists, Fregean particularism argues that perception is constitutively relational, but with representationalists it argues that it is constitutively representational.

 

Fregean particularism is characterized by the following three conditions:

1. The content of any two perceptions e₁ and e₁* that have the same phenomenal character and in which the subject is perceptually related to the same particular α₁ in the same way will include the token singular mode of presentation MOP_rα(α₁), where MOP_rα(α₁) is constituted by employing the perceptual capacity C_α that functions to single out particulars of the type under which α₁ More specifically, MOP_rα(α₁) is the output of employing perceptual capacity C_α that takes particulars of the kind under which α₁ falls as inputs. So MOP_rα(α₁) is constituted by the perceptual capacity employed and the particular α₁ thereby singled out.

2. A perception e₂ that has the same phenomenal character as e₁, but in which the subject is perceptually related to the numerically distinct particular α₂ will be constituted by employing the same perceptual capacity C_α. However, since the input in e₂ is a different particular than in e₁, the ensuing token content MOP_rα(α₂) is different. This is the case, even if α₁ and α₂ are qualitatively identical. So singular modes of presentation are injective: if α₁≠α₂, then MOP_rα(α₁) ≠ MOP_rα(α₂).

3. A hallucination or an illusion that has the same phenomenal character as e₁ is constituted by employing the same perceptual capacity C_α but, since there is no relevant particular present, the perceptual capacity is employed baselessly. As a consequence, the token content MOP_rα(__) is gappy.[1]

 

So we can distinguish four different kinds of token contents of perceptual experience with same phenomenal character:

 

(content of perceiving object α₁ and property-instance π₁)          <MOP_rα(α₁), MOP_rπ(π₁)>

(content of perceiving object α₂ and property-instance π₂)          <MOP_rα(α₂), MOP_rπ(π₂)>

(content of hallucinating object α and property-instance π)         <MOP_rα(__), MOP_rπ(__)>

(content of perceiving α₁ and illusion of property-instance π)    <MOP_rα(α₁), MOP_rπ(__)>

 

Each of these four experiences instantiates the following content type:

 

(content_Type) <MOP_rα[___], MOP_rπ[___]>

where MOP_rα[___] can be tokened by MOP_rα(α₁), MOP_rα(α₂), MOP_rα(α₃), MOP_rα(__), or any other singular mode of presentation of a particular.

 

Chapter 5 takes a step back and traces the way in which excessive demands on the notion of perceptual content invite an austere relationalist account of perception. It argues that any account that acknowledges the role of discriminatory, selective capacities in perception must acknowledge that perceptual states have representational content. The chapter shows that on a relational understanding of perceptual content, the fundamental insights of austere relationalism do not compete with representationalism. Most objections to the thesis that perceptual experience has representational content apply only to austere representationalist accounts, that is, accounts on which perceptual relations to the environment play no explanatory role.

There are two steps to this argument. First I defend the content thesis:

 

Content Thesis:          A subject S’s perceptual state M brought about by being perceptually related to a particular a is constituted by content c in virtue of S representing a.

The Perceptual Content Argument

I. If a subject S perceives a particular a, then S discriminates and singles out a.

II. If S discriminates and singles out a, then S is employing perceptual capacity C_α by means of which S discriminates and singles out a.

III. If S is employing perceptual capacity C_α by means of which S discriminates and singles out a, then S’s perceptual state M brought about by being perceptually related to a and employing C_α is repeatable and has accuracy conditions.

IV. If S’s perceptual state M brought about by being perceptually related to a and constituted by employing C_α is repeatable and has accuracy conditions, then S’s perception is constitutively a matter of representing a in virtue of employing C_α.

V. If S’s perception is constitutively a matter of representing a in virtue of employing C_α, then S’s perceptual state M brought about by being perceptually related to a is constituted by content c in virtue of S representing a.

From I – V.       If S perceives a, then S’s perceptual state M brought about by being perceptually related to a is constituted by content c in virtue of S representing a.

 

Then I argue that perceptual content is relational content.

 

The Relational Content Argument

From I.        If a subject S perceives particular a, then S discriminates and singles out a.

VI. If S discriminates and singles out a, then S is perceptually conscious of a in virtue of discriminating and singling out a.

VII. If S is perceptually conscious of a in virtue of discriminating and singling out a, then S is perceptually conscious of a in virtue of employing perceptual capacity C_α by means of which she discriminates and singles out a.

VIII. Perceptual capacities are by their nature linked to what they single out in the case of an accurate perception.

From I – IV.     If S perceives a particular a, then S’s perceptual state M represents a in virtue of employing C_α.

IX. If S’s perceptual state M represents a in virtue of employing C_α and if perceptual capacities are by their nature linked to what they single out in the case of an accurate perception, then S’s perceptual state M is constituted by relational content rc in virtue of S being perceptually related to a and of S representing a

From I-IX.       If S perceives a (while not suffering from blindsight or any other form of unconscious perception), then S’s perceptual state M is constituted by relational content rc in virtue of S being perceptually related to a and of S representing a.

In the book, I defend each premise. Tomorrow I’ll blog about consciousness.

[1] For an earlier version of this view, see my paper “Perceptual Content Defended”. Noûs, 45 (4): 714-750 (2011).