Although current debates in epistemology and philosophy of mind show a renewed interest in perceptual illusions, there is no systematic work in the philosophy of perception and in the psychology of perception with respect to the concept of illusion and the relation between illusion and error. This book aims to fill that gap.

We often feel that our perceptual experience is richer than what we can express. For instance, when flashed with a large set of letters, we feel that we can see them all, while we can report only a few. However, the nature of this subjective impression remains highly debated: while many favour a dissociation between two forms of consciousness , others contend that the richness of phenomenal experience is a mere illusion. Here we addressed this question with a classical (...) partial-report paradigm now modified to include unexpected items in the unreported parts of the stimuli. We show that even in the presence of unexpected pseudo-letters, participants still felt that there were only letters. Additionally, we show that this feeling reflects an illusion whereby participants reconstruct letters using partial letter-like information. We propose that the feeling of seeing emerges from the interplay between partially accessible information and expectations. (shrink)

de Anima III.10 characterizes akrasia as a conflict between phantasia (“imagination”) on one side and rational cognition on the other: the akratic agent is torn between an appetite for what appears good to her phantasia and a rational desire for what her intellect believes good. This entails that akrasia is parallel to certain cases of perceptual illusion. Drawing on Aristotle's discussion of such cases in the de Anima and de Insomniis , I use this parallel to illuminate the difficult (...) discussion of akrasia in Nicomachean Ethics VII.3, arguing that its account of akrasia as involving ignorance is compatible with, and in fact crucially supplements, the more straightforward account we find elsewhere in the corpus of akrasia as a struggle between desires. (shrink)

This chapter challenges the view that perceptual illusions are mistakes, by first of all emphasizing how the concept of illusions-as-mistakes relies on perspectives unavailable within illusory experiences and introduces norms fixed outside such experiences. A study of ‘rubber hand illusions’ suggests how illusions are not mistaken perceptions, but cases in which perceived objects makes a different kind of sense—in virtue of a norm that is not a fixed, objective standard but is ongoingly engendered within the (...) dynamics of living, perceptual behaviour. This leads to the view that perception is not founded on readymade norms that stand as a past fixed outside living dynamics. Rather, norms are rather a past that ongoingly emerges within living behaviour—they are what I call temporal spandrels of living temporality. (shrink)

Austere relationism rejects the orthodox analysis of hallucinations and illusions as incorrect perceptual representations. In this article, I argue that illusions of optimal motion present a serious challenge for this view. First, I submit that austere-relationist accounts of misleading experiences cannot be adapted to account for IOMs. Second, I show that any attempt at elucidating IOMs within an austere-relationist framework undermines the claim that perceptual experiences fundamentally involve relations to mind-independent objects. Third, I develop a representationalist (...) model of IOMs. The proposed analysis combines two ideas: Evans' dynamic modes of presentation and Fine's relational semantics for identity. (shrink)

I argue that a class of recently-discovered cross-modal illusions gives reason to posit a dimension of content shared across perceptual modalities and to abandon the traditional view according to which perceptual content is exclusively constituted by discrete modality-specific contents.

There are two related points at which J.J. Gibson’s ecological theory of visual perception remains remarkably underspecified: Firstly, the notion of information for perception is not explicated in much detail beyond the claim that it “specifies” the environment for perception, and, thus being an objective affair, enables an organism to perceive action possibilities or “affordances.” Secondly, misperceptions of affordances and perceptual illusions are not clearly distinguished from each other. Although the first claim seems to suggest that any (...) class='Hi'>perceptual illusion amounts to the misperception of affordances, there might be some relevant differences between various ways of getting things wrong. In this essay, Gibson’s notion of “specifying” information shall be reconstructed along the lines of Fred Dretske’s relational theory of information. This refined notion of information for perception will then be used to carve out the distinction between perceptual illusions and the misperception of affordances, with some help from the “Empirical Strategy” (developed by Purves et al.). It will be maintained that there are cases where perceptual illusions actually help an organism to correctly perceive an affordance. In such cases, the prima facie misrendered informational relations involved are kept intact by a set of appropriate transformation rules. Two of Gibson’s intuitions shall thus be preserved: the objectivity of informational relations and the empowerment of the organism as an active perceiver who uses those objective relations to his specific ends. (shrink)

In the last few years there has been an explosion of philosophical interest in perception; after decades of neglect, it is now one of the most fertile areas for new work. Perceptual Experience presents new work by fifteen of the world's leading philosophers. All papers are written specially for this volume, and they cover a broad range of topics to do with sensation and representation, consciousness and awareness, and the connections between perception and knowledge and between perception and action. (...) This will be the book on the philosophy of perception, a fascinating resource for philosophers and psychologists. (shrink)

Investigating perceptual and cognitive abilities of zoo animals might help to improve their husbandry and enrich their daily life with new stimuli. Developing new environmental enrichment programs and devices is hence necessary to promote species-specific behaviours that need to be maintained in controlled environments. As far as we are aware, no study has ever tested the potential benefits of motion illusions as visual enrichment for zoo animals. Starting from a recent study showing that domestic cats are spontaneously attracted (...) by a well-known motion illusion, the Rotating Snake (RS) illusion, we studied whether this illusion could be used as a visual enrichment for big cats. We observed the spontaneous behaviour of three lionesses when three different visual stimuli were placed in their environment: the RS illusion and two control stimuli. The study involved two different periods: the baseline and the RS period, in which the visual stimuli were provided to the lionesses. To assess whether the lionesses were specifically attracted by the RS illusion, we collected data on the number of interactions with the stimuli, as well as on the total time spent interacting with them. To investigate the effect of the illusion on the animals’ welfare, individual and social behaviours were studied and compared between the two periods. The results showed that two lionesses out of three interacted more with the RS stimulus than with the two control stimuli. The fact that the lionesses seemed to be more inclined to interact with the RS stimulus indirectly suggests the intriguing possibility that they were attracted by the illusory motion. Moreover, behavioural changes between the two periods were reported for one of the lionesses, highlighting a reduction in self-directed behaviours and an increase in attentive behaviours, suggesting positive welfare implications. Thus, behavioural observations made before and during the presentation of the stimuli showed that our visual enrichment actually provided positive effects in lionesses. These results call for the development of future studies on the use of visual illusions in the enrichment programs of zoo animals. (shrink)

The claim that perceptual illusions can motivate the existence of sense-data is both familiar and controversial. My aim is to carve out a subclass of illusions that are up to the task, and a subclass that are not. It follows that when we engage the former we are not simply incorrectly perceiving the world outside ourselves, we are directly perceiving a subjective entity: one’s grip on the external world has been marginalized – not fully lost, but once-removed. (...) However, admitting that various illusions do not give evi¬dence for sense-data considerably limits the power of the argument from illusion (Section 6) and brings out its distinctness from the argument from perceptual relativity (Section 7). To reach these conclusions we will examine the role of ambiguity in perception (Section 3), its connection to illusion (Section 4), and the link reference has to every element of this dis¬course (Sections 2 and 5). (shrink)

Three challenges to a unified understanding of delusions emerge from Radden's On Delusion (2011). Here, I propose that in order to respond to these challenges, and to work towards a unifying framework for delusions, we should see delusions as arising in inference under uncertainty. This proposal is based on the observation that delusions in key respects are surprisingly like perceptual illusions, and it is developed further by focusing particularly on individual differences in uncertainty expectations.

Emotions often misfire. We sometimes fear innocuous things, such as spiders or mice, and we do so even if we firmly believe that they are innocuous. This is true of all of us, and not only of phobics, who can be considered to suffer from extreme manifestations of a common tendency. We also feel too little or even sometimes no fear at all with respect to very fearsome things, and we do so even if we believe that they are fearsome. (...) Indeed, instead of shunning fearsome things, we might be attracted to them. Emotions that seem more thought-involving, such as shame, guilt or jealousy, can also misfire. You can be ashamed of your big ears even though we can agree that there is nothing shameful in having big ears, and even though you judge that having big ears does not warrant shame. And of course, it is also possible to experience too little or even no shame at all with respect to something that is really shameful. Many of these cases involve a conflict between one’s emotion and one’s evaluative judgement. Emotions that are thus conflicting with judgement can be called ‘recalcitrant emotions’. The question I am interested in is whether or not recalcitrant emotions amount to emotional illusions, that is, whether or not these cases are sufficiently similar to perceptual illusions to justify the claim that they fall under the same general heading. The answer to this depends on what emotions are. For instance, the view that emotions are evaluative judgments makes it difficult to make room for the claim that emotional errors are perceptual illusions. Fearing an innocuous spider would simply amount to making the error of judging that the spider is fearsome while it is in fact innocuous. This might involve an illusion of some sort, but it certainly does not amount to anything like a perceptual illusion. In this chapter, I argue that recalcitrant emotions are a kind of perceptual illusion.. (shrink)

Perceptual experiences are not immediately responsive to reasons. You see a stick submerged in a glass of water as bent no matter how much you know about light refraction. Due to this isolation from reasons, perception is traditionally considered outside the scope of epistemic evaluability as justified or unjustified. Is perception really as independent from reasons as visual illusions make it out to be? I argue no, drawing on psychological evidence from perceptual learning. The flexibility of (...) class='Hi'>perceptual learning is a way of responding to new epistemic reasons. The resulting perceptual experiences are epistemically evaluable as justified or unjustified. (shrink)

Cross-modal perceptual illusions occur when a stimulus to one modality impacts perceptual experience associated with another modality. Unlike synaesthesia, cross-modal illusions are intelligible as results of perceptual strategies for dealing with sensory stimulation to multiple modalities, rather than as mere quirks. I argue that understanding cross-modal illusions reveals an important flaw in a widespread conception of the senses, and of their role in perceptual experience, according to which understanding perception and perceptual experience (...) is a matter of assembling independently viable stories about vision, audition, olfaction, and the rest. (shrink)

Recent debates between representational and relational theories of perceptual experience sometimes fail to clarify in what respect the two views differ. In this essay, I explain that the relational view rejects two related claims endorsed by most representationalists: the claim that perceptual experiences can be erroneous, and the claim that having the same representational content is what explains the indiscriminability of veridical perceptions and phenomenally matching illusions or hallucinations. I then show how the relational view can claim (...) that errors associated with perception should be explained in terms of false judgments, and develop a theory of illusions based on the idea that appearances are properties of objects in the surrounding environment. I provide an account of why appearances are sometimes misleading, and conclude by showing how the availability of this view undermines one of the most common ways of motivating representationalist theories of perception. (shrink)

Many contemporary theorists charge that naïve realists are incapable of accounting for illusions. Various sophisticated proposals have been ventured to meet this charge. Here, we take a different approach and dispute whether the naïve realist owes any distinctive account of illusion. To this end, we begin with a simple, naïve account of veridical perception. We then examine the case that this account cannot be extended to illusions. By reconstructing an explicit version of this argument, we show that it (...) depends critically on the contention that perceptual experience is diaphanous, or more minimally and precisely, that there can be no difference in phenomenal properties between two experiences without a difference in the scenes presented in those experiences. Finding no good reason to accept this claim, we develop and defend a simple, naïve account of both veridical perception and illusion, here dubbed Simple, Austere Naïve Realism. (shrink)

Do contemporary big-budget blockbuster films like Gravity move something in us that is fundamentally the same as what avant-garde and experimental films have done for more than a century? In a powerful challenge to mainstream film theory, Cinema's Bodily Illusions demonstrates that this is the case. Scott C. Richmond bridges genres and periods by focusing, most palpably, on cinema's power to evoke illusions: feeling like you're flying through space, experiencing 3D without glasses, or even hallucinating. He argues that (...) cinema is, first and foremost, a technology to modulate perception. He presents a theory of cinema as a proprioceptive technology: cinema becomes art by modulating viewers' embodied sense of space. It works primarily not at the level of the intellect but at the level of the body. Richmond develops his theory through examples of direct perceptual illusion in cinema: hallucinatory flicker phenomena in Tony Conrad's The Flicker, eerie depth effects in Marcel Duchamp's Anémic Cinéma, the illusion of bodily movement through onscreen space in Stanley Kubrick's 2001, Godfrey Reggio's Koyaanisqatsi, and Alfonso Cuarón's Gravity. In doing so he combines insights from Maurice Merleau-Ponty's phenomenology of perception and James J. Gibson's ecological approach to perception. The result is his distinctive ecological phenomenology, which allows us to refocus on the cinema's perceptual, rather than representational, power. Arguing against modernist habits of mind in film theory and aesthetics, and the attendant proclamations of cinema's death or irrelevance, Richmond demonstrates that cinema's proprioceptive aesthetics make it an urgent site of contemporary inquiry. (shrink)

Are there illusions of duration? Certainly, many experiences of an event’s duration differ from its measure in clock duration, the measure of that event in seconds, minutes, hours, and so forth. However, I argue that an illusory duration requires more than difference from a real duration; it requires difference from a duration that is relevant to experience. It is plausible to hold that there are many kinds of real duration and reason to question the relevance of all of them. (...) In particular, the interpretation of experienced duration as illusory is typical because it is compared to clock time; the experience of duration goes wrong by being different from a clock measurement of duration. However, I argue that clock duration is not obviously relevant to evaluating the experience of duration.In response, one might hold that it is plausible to evaluate experience by clock duration because clocks more closely match reality than experiences do; on the scale of experience, clock time is no different to real duration. It is not that experienced duration is an illusion because it is merely different from clock duration; it is an illusion because it is different from real duration and we know this because of its difference from clock duration. It is like illusions of size: some object seems to be a size it is not and we know this by comparing it to an object we can otherwise accurately measure by meters.However, unlike size illusions, it is not clear what the ‘real duration’ is against which we should evaluate apparent duration. What is meant by ‘real duration’ involves either an appeal to the duration of substantial absolute time or some kind of duration in things, for example, duration which is the measure of change in some kind of process. is an irrelevant duration; few positions hold that we experience absolute time. As for, if real duration is a measure of change, then, for experienced duration to match clock duration, they must both agree on the relevant change. If there is a difference in what is treated as the real duration, then neither experience nor clocks can be treated as evaluable in terms of the other.Finally, we may have an illusory duration because there are cases of variation between experiences of the same duration. Yet, even here, we may be misled; we may not be directly comparing experiences. We compare the experienced durations through first measuring each in terms of clock duration. If there is a variability in the relationship between clock standard and some relevant standard for experience, then one expects anything accurately meeting one standard to differ from anything accurately meeting the other. The error is holding there is a stable relationship between the standards. This error is not a matter of our experience of duration, and so is not an illusion of duration. (shrink)

Are there illusions of duration? Certainly, many experiences of an event’s duration differ from its measure in clock duration, the measure of that event in seconds, minutes, hours, and so forth. However, I argue that an illusory duration requires more than difference from a real duration; it requires difference from a duration that is relevant to experience. It is plausible to hold that there are many kinds of real duration and reason to question the relevance of all of them. (...) In particular, the interpretation of experienced duration as illusory is typically because it is compared to clock time; the experience of duration goes wrong by being different from a clock measurement of duration. -/- However, I argue that clock duration is not obviously relevant to evaluating the experience of duration. One might hold that it is plausible to evaluate experience by clock duration because clocks more closely match reality than experiences do; on the scale of experience, clock time is no different to real duration. It is not that experienced duration is an illusion because it is merely different from clock duration; it is an illusion because it is different from real duration and we know this because of its difference from clock duration. It is like illusions of size: some object seems to be a size it is not, and we know this by comparing it to an object we can otherwise accurately measure by meters. -/- However, unlike size illusions, it is not clear what the ‘real duration’ is against which we should evaluate apparent duration. What is meant by ‘real duration’ involves either (a) an appeal to the duration of substantial absolute time or (b) some kind of duration in things, e.g., duration which is the measure of change in some kind of process. (a) is an irrelevant duration; few positions hold that we experience absolute time. As for (b), if real duration is a measure of change, then, for experienced duration to match clock duration, they must both agree on the relevant change. If there is a difference in what is treated as the real duration, then neither experience nor clocks can be treated as evaluable in terms of the other. -/- Finally, we may have an illusory duration because there are cases of variation between experiences of the same duration. Yet, even here, we may be misled; we may not be directly comparing experiences. We compare the experienced durations through first measuring each in terms of clock duration. If there is a variability in the relationship between clock standard and some relevant standard for experience, then one expects anything accurately meeting one standard to differ from anything accurately meeting the other. The error is holding there is a stable relationship between the standards. This error is not a matter of our experience of duration, and so is not an illusion of duration. (shrink)

This book aims to present trompe-l'oeil painting as an ambigous aesthetic ideal offered by early modern theory of art. It embodies the idea of an image identical to what it represents. It is interpreted in terms of perceptual and aesthetic illusion, mimesis, diegesis, play, irony and scientific illustration.

Perception of the external world is an essential part of the animal (including human) life, both as a source of knowledge and as a way to survive. Medieval authors accepted this view, and despite general concerns about the reliability of the senses in the acquisition of certain and objective knowledge, they thought that for the most part our perceptual system gets things right when it comes to the perceptual features of things—but not always. Our article focuses on thirteenth- (...) and fourteenth-century philosophical discussions of illusions and other types of perceptual errors. Reception of incorrect information, misjudgments concerning perceptual objects, the binding problem, and similar cases that explain perceptual errors will be analyzed. We discuss what might be called medieval Aristotelian/Avicennian theories of perception and the internal senses (drawing mainly from Albertus Magnus and Thomas Aquinas), as well as the so-called perspectivist accounts of perception, especially that by Alhacen. Finally, we take up a debate between Peter Auriol and his critics, which contains elements that can be seen as precursors of later skeptical worries. The concern here is that, just like in contemporary discussions leading to disjunctivism, the absence of a secure way to distinguish between veridical and non-veridical perception leads to a general worry about the reliability of our experience of the world. (shrink)

This book explores the important yet neglected relationship between the philosophy of time and the temporal structure of perceptual experience. It examines how time structures perceptual experience and, through that structuring, the ways in which time makes perceptual experience trustworthy or erroneous. -/- Sean Power argues that our understanding of time can determine our understanding of perceptual experience in relation to perceptual structure and perceptual error. He examines the general conditions under which an experience (...) may be sorted into different kinds of error such as illusions, hallucinations, and anosognosia. Power also argues that some theories of time are better than others at giving an account of the structure and errors of perceptual experience. He makes the case that tenseless theory and eternalism more closely correspond to experience than tense theory and presentism. Finally, the book includes a discussion of the perceptual experience of space and how tenseless theory and eternalism can better support the problematic theory of naïve realism. -/- Philosophy of Time and Perceptual Experience originally illustrates how the metaphysics of time can be usefully applied to thinking about experience in general. It will appeal to those interested in the philosophy of time and debates about the trustworthiness of experience. (shrink)

Despite their importance in the history of philosophy and in particular in the work of Aristotle and Kant, mental capacities have been neglected in recent philosophical work. By contrast, the notion of a capacity is deeply entrenched in psychology and the brain sciences. Driven by the idea that a cognitive system has the capacity it does in virtue of its internal components and their organization, it is standard to appeal to capacities in cognitive psychology. The main benefit of invoking capacities (...) in an account of the mind is that it allows for an elegant counterfactual analysis of mental states: it allows us to analyze mental states on three distinct yet interrelated levels. A first level of analysis pertains to the function of mental capacities. A second level of analysis pertains to the mental capacities employed, irrespective of the context in which they are employed. A third level of analysis pertains to the mental capacities employed, taking into account the context in which they are employed. This paper develops an account of perceptual capacities. This account involves an analysis of their function, their individuation and possession conditions, the relation between perceptual capacities and their employment, as well as their informational and neural base conditions. (shrink)

In rubber hand illusions and full body illusions, touch sensations are projected to non-body objects such as rubber hands, dolls or virtual bodies. The robustness, limits and further perceptual consequences of such illusions are not yet fully explored or understood. A number of experiments are reported that test the limits of a variant of the rubber hand illusion. Methodology/Principal Findings -/- A variant of the rubber hand illusion is explored, in which the real and foreign hands (...) are aligned in personal space. The presence of the illusion is ascertained with participants' scores and temperature changes of the real arm. This generates a basic illusion of touch projected to a foreign arm. Participants are presented with further, unusual visuotactile stimuli subsequent to onset of the basic illusion. Such further visuotactile stimulation is found to generate very unusual experiences of supernatural touch and touch on a non-hand object. The finding of touch on a non-hand object conflicts with prior findings, and to resolve this conflict a further hypothesis is successfully tested: that without prior onset of the basic illusion this unusual experience does not occur. Conclusions/Significance -/- A rubber hand illusion is found that can arise when the real and the foreign arm are aligned in personal space. This illusion persists through periods of no tactile stimulation and is strong enough to allow very unusual experiences of touch felt on a cardboard box and experiences of touch produced at a distance, as if by supernatural causation. These findings suggest that one's visual body image is explained away during experience of the illusion and they may be of further importance to understanding the role of experience in delusion formation. The findings of touch on non-hand objects may help reconcile conflicting results in this area of research. In addition, new evidence is provided that relates to the recently discovered psychologically induced temperature changes that occur during the illusion. (shrink)

Perception is conscious: perceiving involves a first-person experience of what’s perceived. It’s widely held that these perceptual experiences are independent of what's perceived. Viewing two visually indiscriminable #2 pencils would involve the same experience, despite viewing different objects. It’s also widely held that conscious perception enables thinking about what's perceiving. When you see one of those pencils you can think, THAT is a pencil. Some philosophers, including John McDowell and John Campbell, have suggested that these two features engender a (...) puzzle: how can perceptual experiences make perceived objects available for thought when they’re independent of those objects? This dissertation is a collection of four papers which address this question. -/- The first (chapter 2) argues that, under two minimal assumptions, conscious perception makes objects available for thought only if experience is not object independent. The second (chapter 3) argues that conscious perception makes objects available for thought by enabling voluntarily attention to them. The third (chapter 4) integrates empirical work on multiple-object tracking and philosophical work on attention to argue that conscious perception isn’t mediated by the construction of representations within the visual system. The fourth (chapter 5) uses philosophical methods and neurophysiology to give an account of the role of experience itself in how perception makes objects available for thought. A concluding chapter combines and extends results from the previous chapters to give a naive realist (vs representationalist) account of perceptual experience. -/- The questions about perceptual experience addressed in this dissertation (object dependent or independent? naive realist or representationalist?) are fundamental to our understanding of experience. Not only do they get at its basic nature, but their answers constrain how we might give scientifically respectable, or naturalistic, explanations of experience as well as how we might explain perceptual hallucinations and illusions. (shrink)

Much contemporary discussion of perceptual experience can be traced to two observations. The first is that perception seems to put us in direct contact with the world around us: when perception is successful, we come to recognize— immediately—that certain objects have certain properties. The second is that perceptual experience may fail to provide such knowledge: when we fall prey to illusion or hallucination, the way things appear may differ radically from the way things actually are. For much of (...) the twentieth century, many of the most important discussions of perceptual experience could be fruitfully understood as responses to this pair of observations. (shrink)