Appearance and Illusion

In my dissertation, I consider how best to account for two central intuitions about the nature of perceptual experience: direct perception, the idea that what we are immediately aware of in perception are objects in the world around us; and perceptual error, the idea that perception can sometimes be misleading or mistaken. Despite the intuitiveness of these ideas, they can seem to be in conflict with each other. If perception simply puts us into direct contact with objects in the environment, how could it ever be mistaken? Resolving this tension is central to the development of a satisfying theory of perceptual experience. I reject representationalist approaches to this problem, develop an alternative, relational view of perception based on the idea that perception involves acquaintance with objects in the environment, and relate this view to empirical theories of perception. I conclude by sketching an account of how a relational view of perception can account for perceptual justification and knowledge.

Veridical perception and illusory perception seem to be two sides of the same coin.

Journal of Consciousness Studies, 2002

In this paper I explore a brand of scepticism about perceptual experience that takes its start from recent work in psychology and philosophy of mind on change blindness and related phenomena. I argue that the new scepticism rests on a problematic phenomenology of perceptual experience. I then consider a strengthened version of the sceptical challenge that seems to be immune to this criticism. This strengthened sceptical challenge formulates what I call the problem of perceptual presence. I show how this problem can be addressed by drawing on an enactive or sensorimotor approach to perceptual consciousness. Our experience of environmental detail consists in our access to that detail thanks to our possession of practical knowledge of the way in which what we do and sensory stimulation depend on each other. Traditional scepticism about perceptual experience questions whether we can know that things are as we experience them as being. This paper targets a new form of scepticism about experience that takes its start from recent work in perceptual psychology and philosophy of mind. The new scepticism questions whether we even have the perceptual experience we think we have. According to the new scepticism, we have radically false beliefs about what our perceptual experience is like. Perceptual consciousness is a kind of false consciousness; a sort of confabulation. The visual world is a grand illusion. The new scepticism raises important questions for philosophy, psychology, and consciousness studies. What is the character of our perceptual experience? And who does the sceptic mean by 'we' anyway? Ordinary perceivers? Ordinary perceivers in unusual reflective contexts? Or psychologists and philosophers? These are surprisingly difficult questions. I argue, in what follows, that the new scepticism, and perhaps also the new perceptual psychology it has spawned, rests on a misguided and overly simplistic account of perceptual phenomenology.

2013

The central problem of the dissertation is the question whether our perceptual states have content. While debates about the nature of perceptual content have been common in the philosophy of perception, a recent discussion questioned whether perception has intentional content at all. Relationalism defends the view that perception is not a form of representation, that it cannot be accurate or inaccurate, that it does not have a content which would give to perception the ability to represent or misrepresent the world. Relationalism is a serious challenge for intentionalism, the view that perceptual states have intentional content and can be accurate or inaccurate. The present dissertation analyses the different aspects of this conflict between relationalism and intentionalism. The central claim of the book is that the relationalist explanation of perception is insufficient and that a theory of intentional content for perception is needed in order to explain the different aspects of perceptual experience, especially perceptual illusions. Relationalism must reduce cases where we fail to see to cases of blindness, i.e. cases where we do not stand in an appropriate relation to a certain object or property, cases where we are blind to that object or property. It will be claimed that certain cases of illusions can be explained as such cases of a failure to see due to blindness. But other types of illusions cannot be treated in the same way. It will be claimed that we need the notion of inaccurate (or false) content to explain at least a certain type of common perceptual illusions. It will also be claimed that only intentionalism can give a coherent explanation of such illusions. The critical part of the book against relationalism will be complemented by a positive defense of intentionalism and perceptual content. This second part of the book offers first a teleo-semantic account of the intentional content of perception. The view is defended here that the content of perceptual states depends on their causal relations and on the functions these states have for systems which use them. Finally, the nature of perceptual content is specified as a Russellian propositional content. The dissertation finishes with the claim that such a view of content counters the relationalist objections against intentional content. Perceptions can have content and can involve a direct relation to external objects and their properties.

Frontiers in Human Neuroscience, 2015

Although a visual illusion is often viewed as an amusing trick, for the vision scientist it is a question that demands an answer, which leads to even more questioning. All researchers hold their own chain of questions, the links of which depend on the very theory they adhere to. Perceptual theories are devoted to answering questions concerning sensation and perception, but in doing so they shape concepts such as reality and representation, which necessarily affect the concept of illusion. Here we consider the macroscopic aspects of such concepts in vision sciences from three classic viewpoints-Ecological, Cognitive, Gestalt approaches-as we see this a starting point to understand in which terms illusions can become a tool in the hand of the neuroscientist. In fact, illusions can be effective tools in studying the brain in reference to perception and also to cognition in a much broader sense. A theoretical debate is, however, mandatory, in particular with regards to concepts such as veridicality and representation. Whether a perceptual outcome is considered as veridical or illusory (and, consequently, whether a class of phenomena should be classified as perceptual illusions or not) depends on the meaning of such concepts.

Philosophical Issues, 2016

2017

Author(s): Sethi, Umrao | Advisor(s): Campbell, John J; Ginsborg, Hannah | Abstract: 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 do...

2012

This paper replies to objections from perceptual distortion (blur, perspective, double vision, etc.) against the representationalist thesis that the phenomenal characters of experiences supervene on their intentional contents. It has been argued that some pairs of distorted and undistorted experiences share contents without sharing phenomenal characters, which is incompatible with the supervenience thesis.

Philosophical Studies, 2007

Early modern empiricists thought that the nature of perceptual experience is given by citing the object presented to the mind in that experience. Hallucination and illusion suggest that this requires untenable mind-dependent objects. Current orthodoxy replaces the appeal to direct objects with the claim that perceptual experience is characterized instead by its representational content. This paper argues that the move to content is problematic, and reclaims the early modern empiricist insight as perfectly consistent, even in cases of illusion, with the realist contention that these direct objects of perception are the persisting mind-independent physical objects we all know and love.

Ecological …, 1992