The Foundations of Perception

 

Yesterday, I gave a general overview of my forthcoming book. Today, I’ll lay out the foundations on which the rest of the book builds: the general and particular elements of perception. Chapter 1 addresses the particular elements of perception, Chapter 2 its general elements.

The phenomenon of perceptual particularity has received remarkably little attention in recent philosophical work. It is high time that this change. After all, the central role of perception in our epistemic and cognitive lives is to provide us with knowledge of particulars in our environment, justify our beliefs about particulars, ground demonstrative reference, and yield singular thoughts. Chapter 1 argues for the particularity thesis:

Particularity thesis:        A subject’s perceptual state M brought about by being perceptually related to the particular α is constituted by α.

The particularist accepts, the generalist rejects the particularity thesis. The particularity thesis entails that if Kim first sees cup1 and then sees cup2, then she is in two distinct token perceptual states—even if she does not notice the switch. More generally, the thesis entails that if M is a perceptual state brought about by being perceptually related to the particular α, and M* is a state brought about by being perceptually related to a numerically distinct particular β (and not perceiving α), then M and M* are distinct perceptual states—even if α and β are qualitatively identical.

The relevant particulars perceived can be objects, events, or property-instances in our environment. It is uncontroversial that objects and events are particulars. Arguably, however, we are not just perceptually related to objects and events, but also to property-instances—for example, instances of shapes, sizes, and color properties. To support this idea, note that the perceptual relation is a kind of causal relation. So when we perceive, say, the shape of the cup in front of us, that shape must be causally efficacious—otherwise we could not perceive it. Thus, given plausible assumptions about causation, the shape of the cup must be a concrete spatio-temporal particular rather than a universal.[1]

A key distinction is between phenomenological particularity and relational particularity.[2] When a subject consciously perceives her environment, she is perceptually conscious of a particular. Now, our experience can be as of a particular, even if we are not in fact perceptually related to a particular. After all, when we suffer a non-veridical hallucination as of, say, a yellow rubber duck, it sensorily seems to us that there is a yellow rubber duck where in fact there is no such duck. So our phenomenal character can be as of a particular even if we are not perceptually related to that particular. In this sense, perceptual experiences are (as) of particulars. We can call this aspect of phenomenal character phenomenological particularity.

Phenomenological particularity:       A mental state manifests phenomenological particularity if and only if it phenomenally seems to the subject that there is a particular present.

A mental state manifests phenomenological particularity if and only if the particularity is in the scope of how things seem to the subject: phenomenological particularity does not require that there be a particular that seems to the subject to be present, just that it seems to the subject that there is a particular present. Every perceptual experience (as) of a particular manifests phenomenological particularity. Indeed it is unclear what it would be to have a perceptual experience that seems to be of a material, mind-independent particular without it sensorily seeming to the subject that such a particular is present. If a subject has an experience that is intentionally directed at a particular and subjectively indistinguishable from perceiving a particular, it will seem to her as if she is experiencing a particular—regardless of whether she is in fact perceptually related to a particular, or is suffering an illusion or hallucination as of a particular. So phenomenological particularity is a feature of any perceptual experience—be it a perception, a hallucination, or an illusion.

We can distinguish the uncontroversial idea that perceptual experience manifests phenomenological particularity from the controversial idea that perception is characterized by relational particularity. A mental state is characterized by relational particularity if and only if the mental state is constituted by the particular perceived. More precisely:

Relational particularity:         A subject’s perceptual state M brought about by being perceptually related to the particular α is characterized by relational particularity if and only if M is constituted by α.

It is relational particularity that generalists and particularists disagree about, not phenomenological particularity: the particularity thesis entails, and the generalist denies, that accurate perceptual states are characterized by relational particularity. My argument in support for the particularity thesis goes as follows:

 

The Particularity Argument

I. If a subject S perceives particular a, then S discriminates and singles out a (as a consequence of being perceptually related to a).

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

 

There is a lot to be said in support of each of the three premises and I do that in Chapter 1 of the book. Here I will just say that perception grounds demonstrative reference, definite descriptions, de re mental states such as singular thoughts, and it fixes the reference of singular terms. Moreover, perception provides us with knowledge of particulars in our environment and justifies singular thoughts about particulars. By providing an argument for the thesis that perceptual states are constituted by particulars that does not itself depend on perception playing these epistemological and cognitive roles, Chapter 1 gives an explanation of how it is that perception can play these roles in our epistemic and cognitive lives.

Chapter 2 provides an account of the general elements of perception by developing the notion of perceptual capacities. Drawing on work in cognitive psychology, neuroscience, and developmental psychology, the chapter develops a comprehensive theory of perceptual capacities. This theory includes an account of the function of perceptual capacities, their individuation and possession conditions, the physical and informational base of perceptual capacities, as well as their repeatability, fallibility, and the asymmetry of their employment in perception on the one hand and hallucination and illusion on the other.

In a nutshell the idea is that perceptual capacities function to discriminate and single out mind-independent particulars that is, particulars of a specific type in our environment. A perceptual capacity is individuated by the mind-independent particulars that the perceptual capacity functions to single out. A subject possesses a perceptual capacity if and only if she would be in a position to discriminate and single out a particular of the type that the capacity functions to discriminate and single out if she were perceptually related to such a particular (and various conditions hold).

Perceptual capacities are fallible: so if a subject possesses a perceptual capacity, she can employ it either while fulfilling its function or while failing to fulfill its function, such that there is no difference at the level of employing the capacity but only a difference at the level of fulfilling its function. The subject employs the capacity without fulfilling its function if she fails to single out the particular that she purports to single out by employing the capacity. She employs the capacity while fulfilling its function if she singles out the particular that she purports to single out. While perceptual capacities are fallible, there is an asymmetry between employing perceptual capacities in perception and employing the same capacity in hallucination or illusion: The employment of a perceptual capacity in cases in which the capacity fulfills its function is metaphysically more basic than the employment of the capacity in cases in which the capacity fails to fulfill its function. A necessary condition for a capacity to be a perceptual capacity is that it is repeatable.

If a subject is employing a perceptual capacity, then there is a physical base of employing the capacity that is constituted by physical processes, events, and structures (such as the neural activity) of the subject who is employing the capacity. Finally, if a subject is employing a perceptual capacity, then there is an informational base of employing the capacity that is constituted by the subpersonal psychological mechanism (information processing, computations, and other subpersonal functional states, events, and processes) of the subject who is employing the capacity.

There is good evidence that perceptual content and perceptual capacities are nonconceptual. The thesis that perceptual content is constituted by employing perceptual capacities allows for a substantive way of analyzing perceptual content as nonconceptual. However, the thesis is also compatible with understanding (at least some) perceptual capacities as conceptual capacities. Indeed one of the benefits of analyzing perceptual content as constituted by perceptual capacities is that it allows one to sidestep the largely terminological debate over whether perceptual content is conceptual or nonconceptual.

The rest of the book exploits this view of the general and particular elements of perception to develop a unified account of content (Part II), consciousness (Part III), and evidence (Part IV). Tomorrow, I’ll blog about Part II.

 

[1] For a defense of the thesis that property-instances are particulars to which we are perceptually related in much the way that we can be perceptually related to objects and events, see my paper “Ontological Minimalism about Phenomenology”. Philosophy and Phenomenological Research, 83 (1): 1-40 (2011).

[2] I introduce this distinction in my paper “The Particularity and Phenomenology of Perceptual Experience”. Philosophical Studies, 149 (1): 19-48 (2010) and develop it further in “Perceptual Particularity”. Philosophy and Phenomenological Research, 93 (1): 25-54 (2016).

 

Header image: Gerhard Richter, Abstraktes Bild (1995)

11 Comments

  1. Nico Orlandi

    Hi Susanna! Thanks for the great post and for the wonderfully rich book. I have a general question about perceptual capacities and then also a question about premise II of the particularity argument.

    The general question about perceptual capacities is whether you think that they constitute a unified natural kind. I suspect that the book will answer this question. But I am wondering whether you think that perceptual capacities in the different modalities, and even within a single modality, have enough in common to make up a unified set.

    About premise II, I worry about whether it relies on an act-object conflation. The premise says:

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

    My worry is: discriminating and singling out are acts (or processes) that pick out the object a and that produce the mental state M. While it may be plausible to think (in externalist spirit) that the content of the mental state M is constituted by the object picked out, why think that the mental state is also constituted by discriminating and singling out?

    • Hi Nico, Thanks for dropping in. And thank you for raising these excellent concerns with your typical razor sharpness.

      In response to your general question: you’re right, of course, that perceptual capacities differ significantly from each other. Perceptual capacities come in many varieties: there are perceptual capacities to discriminate luminance, motion, quantities, size, pitch, tone, and distances to name just a few. Despite their differences, I do believe they form a natural kind in that they all have the same type of function (to discriminate and single out environmental particulars), the same individuation conditions (they’re individuated by the mind-independent particulars they function to single out), the same possession conditions, the same kind of physical base and informational base conditions, they are all fallible and their relation between their employment in perception vs their employment in hallucination and illusion is asymmetric etc.

      • In response to your question about Premise II of the particularity argument:

        Say you are seeing a field of flowers that are shades of red and yellow. You can employ your capacity to discriminate between red and yellow and thus be aware of a field of red and yellow flowers. Alternatively, you can employ your capacity to discriminate between crimson, scarlet, and vermilion, and between lemon, mustard, and chartreuse and thus be aware of the colors in front of you in a more fine-grained way.

        Both are perfectly fine ways of perceiving the colors of the flowers. The second way will give rise to a mental state that is more fine-grained with regard to the color of the flowers.

        To make the case more carefully, say f I see a patch of vermilion. I can discriminate and single it out by using my perceptual capacity to discriminate and single out red from other colors. Or I can discriminate and single it out by using my more fine-grained perceptual capacity discriminate and single it out by using my perceptual capacity to discriminate and single out vermilion from other colors. Both are good ways to single out the patch of vermilion. But I will see the patch in different ways.

        Insofar as which perceptual capacities I employed has an affect on how I’m aware of the color of the flowers, it would be odd to say that the perceptual state brought about by employing these capacities is constituted only be the particulars singled out and not also by the perceptual capacities employed by means of which these particulars are singled out.

        There are other more technical ways of motivating the idea that connect to Frege’s distinction between sense and reference, but the ideas above are perhaps the most intuitive ways of motivating the idea.

        Thanks again for raising these questions!

    • Hi Dirk,

      Great question. There are complex interactions between neural structures and computational networks, such as subpersonal psychological mechanisms: neural structures carry the information on which computational networks operate. While there are such complex interactions we can distinguish between the level of information processing and the physical, neural level that grounds the information processing.

Comments are closed.