Philosophy of Perception

A Contemporary Introduction

William Fish

• Publisher: Routledge
• Year: 2021
• ISBN:
  9781351049481
• Edition: 2
• Topic: Philosophy
• Subtopic: Epistemology in Philosophy

The philosophy of perception investigates the nature of our sensory experiences and their relation to reality. In the second edition of this popular book, William Fish introduces the subject thematically, setting out the major theories of perception together with their motivations and attendant problems. While providing historical background to debates in the field, this comprehensive overview focuses on recent presentations and defenses of the different theories, and looks beyond visual perception to take into account the role of other senses.

The second edition organizes the contents into two main parts: the first deals with philosophical theories of perception, and the second covers key topics and issues in perception as they are discussed in philosophy, cognitive science, and psychology. Two completely new chapters have been added – one on color and color vision; and a second on the interaction between sense modalities – and other chapters have been significantly updated to include discussion of topics such as pre-twentieth-century philosophy of perception, phenomenal intentionality, color adverbialism, predictive processing approaches to perception, ecological approaches to perception, and in-depth discussions of the non-visual senses. Additional updates include fuller and easier-to-understand explanations of some important views that were glossed over in the first edition and greater coverage of research from the last 25 years. All chapter summaries, references, and Suggested Reading lists at the end of each chapter have been brought up to date and the volume now includes a more extensive index at the back of the book.

Key Features and Benefits:

• The only single-authored textbook on philosophy of perception currently available
• Devoted to contemporary theories and topics, but with appropriate historical coverage for fuller understanding of contemporary work
• Each chapter includes a chapter overview, questions for further consideration, and an annotated list of Suggested Reading

Includes coverage of topics like:

• the phenomenal principle
• perception and hallucination
• perception and content
• naïve realism and disjunctivism
• intentionalism and representationalism
• the nature of content
• qualia theories and phenomenal intentionality
• perception and empirical science
• color and color science
• theories of non-visual perception
• Molyneux's problem
• cross-modal illusions
• multimodality

Key Changes to the Second Edition

• The division of the book into two major parts: Part I on philosophical theories of perception, Part II on key interdisciplinary topics in perception
• The addition of two new chapters on color and color vision, and interaction between different sense modalities
• More topics from the last 25 years of philosophy of perception
• Combined chapters on belief acquisition theories and intentional theories into one larger chapter
• More material on the growing intersection of the philosophy and psychology of perception
• Includes coverage of Molyneux's problem and of cross-modal illusions
• Updated chapter summaries, references, and Suggested Reading lists at the end of each chapter
• A summary table and a more extensive index

1 Introduction

Overview

In this chapter we begin by introducing two hats that a philosophical theory of perception needs to wear. The first is the epistemological hat, which focuses on perception’s role of providing us with information about the external world; the second is the phenomenological hat, which focuses on the conscious aspects of perceptual experiences. By focusing on these two hats – these two different jobs that a theory of perception must play – we can identify “tests” for an adequate philosophical theory of perception.

The remainder of the chapter then considers the way that philosophical thinking about perceptual experience developed from Aristotle through the Modern Philosophers, as the theories that were developed and the assumptions that shaped them also serve to set the scene for the development of the philosophy of perception as an independent sub-discipline in the twentieth century.

Over the course of this book, we will be thinking philosophically about our capacity for sense perception – our capacity to perceive the world and our bodies by means of our sense organs.

The Two Hats

If one is of a scientific bent, one might wonder just what the role of philosophical theorizing about perception is: Isn’t empirical science in the process of discovering what the nature of a perceptual experience is and what is going on when we perceive? The relationship between the philosophy of perception and the associated sciences of the mind will be discussed in more detail in Part II, but for now, let us simply note that philosophical thinking about perception has a remit that is broader than that of the sciences. In particular, philosophical theorizing about perception is informed in part by considerations from other branches of philosophy.

So whilst philosophers are indeed concerned with many of the questions that concern empirical investigators – questions of how our capacity to perceive is related to our brains, bodies, and environment, for instance – philosophical theories of perception are also explicitly fashioned to take more philosophical considerations into account. Two considerations that are of particular importance to the philosophy of perception are the following:

Epistemology: One of the main reasons for philosophical interest in perception is that it is the primary source of our knowledge of the world in which we live. So any philosophical theory of perception is going to both inform, and be informed by, epistemological considerations. One consideration for a theory of perception, then, will be how well it can make sense of perception’s role as a source of empirical knowledge.

Phenomenology: Perceptual experiences are paradigmatically conscious experiences: they have a phenomenology or there is, in Nagel’s influential terminology, something it is like to perceive (1974/1979). And given that there is something it is like to perceive, we can ask what it is like to perceive: what, specifically, it is like to see a pink elephant, to smell coffee, or to touch sandpaper? A further test of a philosophical theory of perception will be how accurately it can capture what it is like to have perceptual experiences.

To put it metaphorically, these considerations suggest that an adequate philosophical theory of perception has (at least) two different hats to wear – an epistemological hat and a phenomenological hat. How successfully a particular theory wears each of these hats will therefore be an important choice point when it comes to assessing different theories of perception.

Of course, these are not the only important considerations to bear in mind when it comes to evaluating a theory of perception. In addition, there are metaphysical considerations to take into account, such as the fact that any theory of perception will claim that certain things exist, and can hence be assessed in part by querying whether or not these ontological commitments are metaphysically acceptable given the alternatives available. Furthermore, as we shall see, certain philosophical theories of perception incorporate metaphysical commitments about the world itself; if there are reasons to think that these commitments are mistaken, this will constitute a problem with that theory of perception. And finally, whilst it is true that philosophers of perception have a range of concerns that distinguish them from empirical scientists, the conceptual tools they use in philosophical thinking about perceptual experience have often been forged by empirical science. So despite the differences in emphasis, science does exert a significant influence on the philosophy of perception, in part by providing conceptual tools that are then utilized in developing philosophical theories, and in part by discovering various phenomena that philosophical theories of perception are then required to accommodate.

The Interaction of Phenomenology, Epistemology, Metaphysics, and Science: Vision in Modern Philosophy

Before we move on to consider the way the philosophy of perception developed as a distinct sub-discipline in the twentieth century, it would be instructive to sketch how these considerations – phenomenology, epistemology, metaphysics, and the science of the time – worked together to shape discussions of the nature of perception in the Modern philosophers. These discussions exert a significant influence on subsequent theorizing in the philosophy of perception in at least two ways. First, they show a tendency to focus on vision as the paradigmatic case of perception; second, they incorporate a particular way of conceiving of the relationship between perception and the world, and hence frame our conception of the concerns that philosophical theories of perception are expected to address.

Prior to the scientific revolution, thinking about perception (like science in general) had been dominated by Aristotelian considerations. For Aristotle, although vision does involve a causal process, it is a process by which the sensible qualities of external objects – such as their colors – are transferred from the object to the perceiver’s mind (1984: Book II). On Aristotle’s hylomorphic view, objects themselves are composites of matter and immaterial form. When we perceive objects, we receive the form of the object without its matter. This process proceeds as follows: air is transparent as it contains a substance which, when fire (or something resembling fire) is present in it, can be “set in movement” – changed or affected – by color. So the first stage of this causal process is that the colored object affects the transparent medium. The now affected transparent medium can then act on the perceiver in turn, which on Aristotle’s view it does by altering – again, changing or affecting – the perceiver’s sense organ. The sense thereby “receives the sensible form of things without the matter” (674), similar to the way in which sealing wax can receive the design of a signet ring without receiving the metal that the ring is made of. In this way, the colors of objects, but not the objects themselves, are transmitted from the object to the medium and from the medium to our eyes, which for animals such as us constitutes our seeing the object.

The Aristotelian view began to fall out of favor as the scientific revolution gathered steam during the early Modern period, however. In place of this hylomorphic physics, a more austere mechanistic physics was developed in which matter had only basic properties, such as size and shape, position and motion. On such a view, there is no scope for vision to involve sensible qualities such as color being transmitted to the perceiver, as objects that possess only basic properties do not actually have such qualities to be transmitted. So where Aristotle thought that what is transferred to the mind is the form of what we perceive, on the modern mechanistic view the way in which perceptible objects are perceived is by mechanical contact: by a process of things bumping and pushing, coming into contact with one another. Descartes thus explains the mechanisms of visual perception by analogy to the way a blind man navigates his environment by means of a stick. What matters here, Descartes suggests, is simply how one thing pushes against another – objects affect the stick by resisting its movements and the stick, in turn, pushes against the man’s hand: nothing needs to “issue from the bodies and pass along his stick to his hand” (1637/2001: 153). Sight, suggests Descartes, works in a similar way: when light is reflected from an object, this affects the light in a particular way (in Descartes’ view, by giving the particles that constitute it a unique “spin” that correlates with one of the different colors that we experience when we perceive objects). When these particles reach a perceiver’s eye, they push on the retina, and this particular “pushing” excites the nerves of the retina in a distinctive way, which in turn excites the brain, causing the perceiver to have certain sensations.

But the motions which are thus excited in the brain by the nerves affect the soul or mind, which is intimately conjoined with the brain, in different ways, according to their own diversity. And the different affections of our mind, or thoughts, immediately following upon these motions, are called perceptions of the senses, or in common speech, sensations.

(1644/1985: 280)

So sensations do correlate with some feature of the nature of the object – different objects affect the brain in different ways according to their own diversity – but whilst these sensations do enable us to perceive the world, like the sensations the blind man receives from his stick, Descartes cautions us against simply assuming that they resemble the objects with which we began.

So in Descartes, we find a philosophical theory of visual perception that is both constrained by features of the science at the time – in particular, the austere metaphysical picture of the nature of matter – yet is also shaped by the conceptual tools it makes available, such as the mechanistic view of causation as involving particles engaged in billiard ball-type collisions or interactions. When viewed through a philosophical lens, however – in particular, when we ask how well the theory wears the epistemological and phenomenological hats – this picture appears less than satisfactory.

As far as the phenomenological hat is concerned, to the extent that the theory has any kind of story to tell about what it is like for us to perceive, it is essentially stipulative; according to the theory, it is the sensations that are ultimately caused by the perceptual process that account for what it is like to have conscious perceptual experiences. To this extent, then, the theory could be claimed to capture what it is like for us to perceive – it is a matter of the particular sensations that occur at the end of the causal chain. Yet we might have two concerns with such a view. First is that there is no non-stipulative explanation of why it is like this to have any given experience – this is just accounted for by the nature of the sensations that happen to occur when human minds are affected in a certain way; there is no deeper explanation of why this kind of experience corresponds with these aspects of the world. Second, when we talk about “what it is like” to perceive, it can be natural to think that part of capturing the phenomenology of perception would be to capture the sense that, in vision at least, when we experience our environment, our experiences appear to give us some kind of access to the nature of the external world. Yet, as Descartes makes clear, on this picture there is no reason to think that our experiences resemble the external world at all.

We might also choose to express this underlying disquiet in epistemological terms: on the face of it, it appears as though one type of knowledge that we acquire from visual experience is knowledge of what the external world is really like. Yet when we look at this theory, we find that it is not clear that it can accommodate this. The story it has about how we get knowledge of the world on the basis of perception turns on the analogy to the blind man’s stick. In this case, we know that the sensations caused by the stick meeting a sidewalk kerb do not in any way resemble that kerb, yet despite this, the man can still acquire knowledge about the location and size of the kerb on their basis, which can enable him to successfully navigate his environment. In this way, the perceptual process thus understood can give us knowledge of the external world. However, this knowledge is not quite what we were looking for from our discussion of the phenomenological hat: one thing that we cannot know from our perceptual experiences, thus understood, is what the world is really like – as Descartes says, we cannot assume that the sensations we enjoy bear any resemblance to the external objects themselves.

On this picture, then, our primary mode of conscious awareness in perception is awareness of sensations, which are understood as fundamentally distinct from, albeit caused by, external objects. To the extent that we can be said to be aware of external objects by having perceptual experiences, then our awareness of the world is indirect – we are aware of the world by being aware of the sensations that this world causes. This indirectness can also be framed as a challenge for epistemology. Our primary epistemic access is to the sensations; to the extent that we get knowledge about the world by enjoying these sensations, it is by inference. Just as the blind man infers that there is a curb in front of him by the sensations he receives through the stick (in conjunction with knowledge that these sensations correspond with curbs), we infer that there are objects present in our environment on the basis of the fact that we are having certain sensations, in conjunction with knowledge about the kinds of objects that these sensations correspond with.

Locke develops a similar picture, although he more directly addresses the phenomenological question of explaining what it is like to have visual experiences. Where Descartes had sensations, Locke has Ideas, which have usually been understood as mental objects – the things in our minds that we immediately perceive – that are caused by and represent (by resembling, in part) the objects in the world. Again, influenced by the conceptual tools provided by the science of his day, Locke held a broadly “atomic” theory of ideas, according to which experience furnishes the mind with a store of simple atomic ideas, which could then be combined into more complex “molecules” by the activity of the mind. So although Locke’s view also appears to involve an indirect awareness of the world, and thus often meets similar epistemological criticisms, he does have a more straightforward phenomenological story to tell: the things that we are directly aware of – the things we pre-theoretically take to be external objects – are in fact ideas or mental objects. In some dimensions, such as size, shape, motion, and location – Locke’s primary qualities – the ideas resemble their causes; both ideas and material objects possess primary qualities. In other cases, however, our ideas fail to resemble anything in the objects at all: where qualities such as color, smell, taste, and so on are concerned, these are qualities that are l...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Acknowledgments (First Edition)
• Acknowledgments (Second Edition)
• 1 Introduction
• Part I Philosophical Theories of Visual Perception
• Part II The Philosophy of Perception and the Sciences of the Mind
• 8 Perception and the Nonvisual Sense Modalities
• 9 Multimodality
• References
• Author Index
• Subject Index