Aphantasia is a condition characterised by a deficit of mental imagery. Since several psychopathologies are partially maintained by mental imagery, it may be illuminating to consider the condition against the background of psychological disorder. After outlining current findings and hypotheses regarding aphantasia and psychopathology, this paper suggests that some support for defining aphantasia as a lack of voluntary imagery may be found here. The paper then outlines potentially fruitful directions for future research into aphantasia in general and (...) its relation to psychopathology in particular, including rethinking use of the SUIS to measure involuntary imagery, whether aphantasia offers protection against addiction, and whether hyperphantasia is a potential risk factor for maladaptive daydreaming, among others. (shrink)

Fictions evoke imagery, and their value consists partly in that achievement. This paper offers analysis of this neglected topic. Section 2 identifies relevant philosophical background. Section 3 offers a working definition of imagery. Section 4 identifies empirical work on visual imagery. Sections 5 and 6 criticize imagery essentialism, through the lens of genuine fictional narratives. This outcome, though, is not wholly critical. The expressed spirit of imagery essentialism is to encourage philosophers to ‘put the image (...) back into the imagination’. The weakened conclusion is that while an image is not essential to imagining, it should be returned to our theories of imagination. (shrink)

The problem of amodal perception is the problem of how we represent features of perceived objects that are occluded or otherwise hidden from us. Bence Nanay (2010) has recently proposed that we amodally perceive an object's occluded features by imaginatively projecting them into the relevant regions of visual egocentric space. In this paper, I argue that amodal perception is not a single, unitary capacity. Drawing appropriate distinctions reveals amodal perception to be characterized not only by mental imagery, as Nanay (...) suggests, but also by genuinely visual representations as well as beliefs. I conclude with some brief remarks on the role of object-directed bodily action in conferring a sense of unseen presence on an object's occluded features. (shrink)

Recent research in psycholinguistics suggests that language processing frequently involves mental imagery. This paper focuses on visual imagery and discusses two issues regarding the processing of polysemous words (i.e. words with multiple related meanings or senses) – co-predication and sense-relatedness. It aims to show how mental imagery can illuminate these two issues.

Poetry evokes mental imagery in its readers. But how is mental imagery precisely related to poetry? This article provides a systematic treatment. It clarifies two roles of mental imagery in relation to poetry—as an effect generated by poetry and as an efficient means for understanding and appreciating poetry. The article also relates mental imagery to the discussion on the ‘heresy of paraphrase’. It argues against the orthodox view that the imagistic effects of poetry cannot be captured (...) by prosaic paraphrase, but points to features of poetry that can shape aspects of mental imagery that are liable to be lost in paraphrase. (shrink)

In this article we examine obsessive compulsive disorder (OCD). We examine and reject two existing models of this disorder: the Dysfunctional Belief Model and the Inference‐Based Approach. Instead, we propose that the main distinctive characteristic of OCD is a hyperactive sub‐personal signal of being in error, experienced by the individual as uncertainty about his or her intentional actions (including mental actions). This signalling interacts with the anxiety sensitivities of the individual to trigger conscious checking processes, including speculations about possible harms. (...) We examine the implications of this model for the individual's capacity to control his or her thoughts. (shrink)

What is the relationship between perception and mental imagery? I aim to eliminate an answer that I call perceptualism about mental imagery. Strong perceptualism, defended by Bence Nanay, predictive processing theorists, and several others, claims that imagery is a kind of perceptual state. Weak perceptualism, defended by M. G. F. Martin and Matthew Soteriou, claims that mental imagery is a representation of a perceptual state, a view sometimes called The Dependency Thesis. Strong perceptualism is to be (...) rejected since it misclassifies imagery disorders and abnormalities as perceptual disorders and abnormalities. Weak Perceptualism is to be rejected since it gets wrong the aim and accuracy conditions of a whole class of mental imagery–projected mental imagery–and relies on an impoverished concept of perceptual states, ignoring certain of their structural features. Whatever the relationship between perception and imagery, the perceptualist has it wrong. (shrink)

We often ascribe possibility to the scenes that are displayed by mental or nonmental sensory images. The paper presents a novel argument for thinking that we are prima facie justified in ascribing metaphysical possibility to what is displayed by suitable visual images, and it argues that many of our imagery‐based ascriptions of metaphysical possibility are therefore prima facie justified. Some potential objections to the arguments are discussed, and some potential extensions of them, to cover nonvisual forms of imagery (...) and nonmetaphysical forms of possibility, are endorsed. (shrink)

What triggers the execution of actions? What happens in that moment when an action is triggered? What mental state is there at the moment of action-execution that was not there a second before? My aim is to highlight the importance of a thus far largely ignored kind of mental state in the discussion of these old and much-debated questions: motor imagery. While there have been a fair amount of research in psychology and neuroscience on motor imagery in the (...) last 30 years or so, it is only recently that we start to understand the important role motor imagery plays in action initiation. And if, as these findings suggest, motor imagery plays an important role in action initiation, we can make progress not only in understanding action initiation in general but also in understanding what goes wrong in akratic actions and in relapse actions. Finally, this new picture of action-initiation also has far-reaching consequences for the relation between motivation and causation in naturalistic action-explanations. (shrink)

This paper offers a general theory of privacy, a theory that takes privacy to consist in being free from certain kinds of intrusions. On this understanding, privacy interests are distinct and distinguishable from those in solitude, anonymity, and property, for example, or from the fact that others possess, with neither consent nor permission, personal information about oneself. Privacy intrusions have both epistemic and psychological components, and can range in value from relatively trivial considerations to those of profound consequence for an (...) individual’s dignity, integrity, and autonomy. Thus while the focus of this theory is privacy per se— privacy as being free from certain kinds of intrusions—it has significant implications, discussed briefly, for what properly counts as the content of moral or legal rights to privacy. (shrink)

Maurice Merleau-Ponty is often interpreted as claiming that opportunities for action are directly present in perceptual experience. However, he does not provide much evidence for how or why this would occur, and one can doubt that this is an appropriate interpretation of his phenomenological descriptions. In particular, it could be argued the Merleau-Pontyian descriptions mistakenly attribute pre-perceptual or post-perceptual elements such as allocation of attention or judgment to the perceptual experience itself. This paper argues for the Merleau-Pontyian idea that opportunities (...) for action are present in perceptual experience. It further argues that the phenomenological descriptions can be supported and explained via reference to contemporary research on motor imagery. In particular, it will be argued that non-conscious, covert motor imagery is used to prepare for and regulate skilled actions, and that it is plausible that this imagery combines with perception (likely vision) to create a single experience of the environment as enabling action. The paper will also show that contemporary views on motor imagery are broadly compatible with Merleau-Ponty’s aims. (shrink)

The claim that common sense regards free will and moral responsibility as compatible with determinism has played a central role in both analytic and experimental philosophy. In this paper, we show that evidence in favor of this “natural compatibilism” is undermined by the role that indeterministic metaphysical views play in how people construe deterministic scenarios. To demonstrate this, we re-examine two classic studies that have been used to support natural compatibilism. We find that although people give apparently compatibilist responses, this (...) is largely explained by the fact that people import an indeterministic metaphysics into deterministic scenarios when making judgments about freedom and responsibility. We conclude that judgments based on these scenarios are not reliable evidence for natural compatibilism. (shrink)

This paper introduces a novel conceptualisation of mental imagery; namely, that is grease for the mind’s gears (MGT). MGT is not just a metaphor. Rather, it describes an important and overlooked higher-order function of mental imagery: that it aids various mental faculties discharge their characteristic functional roles. MGT is motivated by reflection on converging evidence from clinical, experimental and social psychology and solves at least two neglected conceptual puzzles about mental imagery. The first puzzle concerns imagery’s (...) architectural promiscuity; that is, its ability to assist diverse mental faculties and perform many different functions when doing so. The second puzzle concerns how to square imagery’s architectural promiscuity with its psychopathological relevance; that is, its being a maintaining cause, and possibly even a partial constituent, of several psychological disorders, including post-traumatic stress disorder, bipolar disorder and major depressive disorder. Mental imagery helps and harms human psychology to extreme degrees and this is something that calls for elucidation. MGT says that instead of facing perplexing heterogeneities here, we instead face a significant unity. On this score, MGT is argued to be superior to the currently dominant conception of imagery in the philosophical literature; namely, as a perception-like state of mind. (shrink)

Historically, mental imagery has been defined as an experiential state - as something necessarily conscious. But most behavioural or neuroimaging experiments on mental imagery - including the most famous ones - don’t actually take the conscious experience of the subject into consideration. Further, recent research highlights that there are very few behavioural or neural differences between conscious and unconscious mental imagery. I argue that treating mental imagery as not necessarily conscious (as potentially unconscious) would bring much (...) needed explanatory unification to mental imagery research. It would also help us to reassess some of the recent aphantasia findings inasmuch as at least some subjects with aphantasia would be best described as having unconscious mental imagery. (shrink)

Mental imagery often occurs during testimonial belief transmission: a testifier often episodically remembers or imagines a scene while describing it, while a listener often imagines that scene as it’s described to her. I argue that getting clear on imagery’s psychological roles in testimonial belief transmission has implications for some fundamental issues in the epistemology of testimony. I first appeal to imagery cases to argue against a widespread “internalist” approach to the epistemology of testimony. I then appeal to (...) the same sort of case to argue for an alternative, externalist view. (shrink)

One distinct interest in self-knowledge concerns whether one can know about one’s own mental states and processes, how much, and by what methods. One broad distinction is between accounts that centrally claim that we look inward for self-knowledge (introspective methods) and those that claim that we look outward for self-knowledge (transparency methods). It is here argued that neither method is sufficient, and that we see this as soon as we move beyond questions about knowledge of one’s beliefs, focusing instead on (...) how one distinguishes, for oneself, one’s veridical visual memories from mere (non-veridical) visual images. Given robust psychological and phenomenal similarities between episodic memories and mere imagery, the following is a genuine question that one might pose to oneself: “Do I actually remember that happening, or am I just imagining it?” After critical analysis of the transparency method (advocated by Byrne 2010, following Evans 1982) to this latter epistemological question, a brief sketch is offered of a more holistic and inferential method for acquisition of broader self-knowledge (broadly following the interpretive-sensory access account of Carruthers 2011). In a slogan, knowing more of the mind requires using more of the mind. (shrink)

Visualizings, the simplest imaginings which employ visual imagery, have certain characteristic features; they are perspectival, for instance. Also, it seems that some but not all of our visualizings are imaginings of seeings. But it has been forcefully argued, for example by M.G.F. Martin and Christopher Peacocke, that all visualizings are imaginings of visual sensations. I block these arguments by providing an account of visualizings which allows for their perspectival nature and other features they typically have, but which also explains (...) how we can visualize things without thereby imagining visual sensations. (shrink)

In this paper, I explore Bach’s idea (Bach, 2000) that null appositives, intended as expanded qua-clauses, can resolve the puzzles of belief reports. These puzzles are crucial in understanding the semantics and pragmatics of belief reports and are presented in a section. I propose that Bach’s strategy is not only a way of dealing with puzzles, but also an ideal way of dealing with belief reports. I argue that even simple unproblematic cases of belief reports are cases of pragmatic intrusion, (...) involving null appositives, or to use the words of Bach, ‘qua-clauses’. The main difference between my pragmatic approach and the one by Salmon (1986) is that this author uses the notion of conversational implicature, whereas I use the notion of pragmatic intrusion and explicature. From my point of view, statements such as ‘‘John believes that Cicero is clever’’ and ‘‘John believes that Tully is clever’’ have got distinct truth-values. In other words, I claim that belief reports in the default case illuminate the hearer on the mental life of the believer, that includes specific modes of presentation of the referents talked about. Furthermore, while in the other pragmatic approaches, it is mysterious how a mode of presentation is assumed to be the main filter of the believer’s mental life, here I provide an explanatory account in terms of relevance, cognitive effects, and processing efforts. The most important part of the paper is devoted to showing that null appositives are required, in the case of belief reports, to explain certain anaphoric effects, which would otherwise be mysterious. My examples show that null appositives are not necessitated at logical form, but only at the level of the explicature, in line with the standard assumptions by Carston and Recanati on pragmatic intrusion. I develop a potentially useful analysis of belief reports by exploiting syntactic and semantic considerations on presuppositional clitics in Romance. (shrink)

What is the mental representation that is responsible for implicit bias? What is this representation that mediates between the trigger and the biased behavior? My claim is that this representation is neither a propositional attitude nor a mere association. Rather, it is mental imagery: perceptual processing that is not directly triggered by sensory input. I argue that this view captures the advantages of the two standard accounts without inheriting their disadvantages. Further, this view also explains why manipulating mental (...) class='Hi'>imagery is among the most efficient ways of counteracting implicit bias. (shrink)

It is often observed that images—including mental images—are in some sense representationally ambiguous. Some, including Jerry Fodor, have added that mental images only come to have determinate contents through the contribution of non-imagistic representations that accompany them. This paper agrees that a kind of ambiguity holds with respect to mental imagery, while arguing (pace Fodor) that this does not prevent imagery from having determinate contents in the absence of other, non-imagistic representations. Specifically, I argue that mental images can (...) represent determinate types of outlays of properties without help from any non-imagistic representations, yet can only become involved in the representation of particular objects through pairing with a non-imagistic representation of the right sort. These points are defended through reflection on the “Picture Principle,” the nature of depiction, and general principles for typing and individuating mental states. (shrink)

Hallucination is a big deal in contemporary philosophy of perception. The main reason for this is that the way hallucination is treated marks an important stance in one of the most hotly contested debates in this subdiscipline: the debate between 'relationalists' and 'representationalists'. I argue that if we take hallucinations to be a form of mental imagery, then we have a very straightforward way of arguing against disjunctivism: if hallucination is a form of mental imagery and if mental (...) imagery and perception have some substantive common denominator, then a fortiori, perception and hallucination will also have a substantive common denominator. (shrink)

Defined as vicarious sensorimotor experiencing, mental imagery is a powerful source of aesthetic enjoyment in everyday life and, reportedly, one of the commonest things readers remember about literary narratives in the long term. Furthermore, it is positively correlated with other dimensions of reader response, most notably with emotion. Until recent decades, however, the phenomenon of mental imagery has been largely overlooked by modern literary scholarship. As an attempt to strengthen the status of mental imagery within the literary (...) and, more generally, aesthetic discipline, this dissertation proposes an analysis positioned at a confluence of literary theory and the cognitive sciences, especially the emergent research framework of embodied cognition. Questions asked throughout the dissertation include the following: a) What are the basic varieties of mental imagery in the reading of literary narrative? b) By what contents or narrative strategies are they most likely to be prompted? c) What is it like to experience a mental image of a particular variety? d) What are its psychophysiological underpinnings? e) How does a mental image of a particular variety relate to perception? f) How does it relate to higher-order meaning-making? Four prototypical imagery varieties are distinguished on the basis of two variables with two values each (referential vs. verbal domain; inner vs. outer stance). Gradual transitions and in-between imagery varieties are acknowledged. The imagery typology and related hypotheses are grounded in introspection but carefully supported with indirect empirical evidence and, whenever possible, formulated so as to facilitate direct validation. (shrink)

Bulk collection involves the mining of large data sets containing personal data, often for a security purpose. In 2013, Edward Snowden exposed large scale bulk collection on the part of the US National Security Agency as part of a secret counter-terrorism effort. This effort has mainly been criticised for its invasion of privacy. I argue that the right moral argument against it is not so much to do with intrusion, as ineffectiveness for its official purpose and the lack of oversight (...) by security cleared legislators. It also lends itself to government "domination" (in Pettit's sense) of those who are subject to it. (shrink)

The paper examines the relationships between the contents of imaginative episodes and the mental images that often play a central role within them. It considers, for example, whether the presence of mental imagery is required for a mental episode to count as an imagining.

The objective of this article is twofold. In the first part, I discuss two issues central to any theoretical inquiry into mental imagery: embodiment and consciousness. I do so against the backdrop of second-generation cognitive science, more specifically the increasingly popular research framework of embodied cognition, and I consider two caveats attached to its current exploitation in narrative theory. In the second part, I attempt to cast new light on readerly mental imagery by offering a typology of what (...) I propose to be its four basic varieties. The typology is grounded in the framework of embodied cognition and it is largely compatible with key neuroscientific and other experimental evidence produced within the framework. For each imagery variety, I make some elementary suggestions as to how it may typically be cued by distinct narrative strategies. (shrink)

I examined the proposition that there are psychological limits on what scientific problems can be solved, and that these limits may be based on a failure to be able to produce imagable, observation-based models for any possible solution, a position suggested by philosopher Colin McGinn in an argument attempting to prove that the mind-body problem is unsolvable. I examined another likely candidate for an unsolvable problem -- the ultimate origin of the universe (i.e., what might have preceded the Big Bang (...) or any other starting point; why there should be something rather than nothing) -- by exploring the reasoning of physicists about this problem and measuring visual imagery frequency and vividness, with the expectation that those who most believed the problem unsolvable would be more frequent/vivid imagers and therefore more affected by the apparent impossibility of producing an imagable solution. Eight physicists were interviewed and imagery frequency and vividness measurements performed using Cohen & Saslona's IDQ-IHS and Marks's VVIQ, respectively. All subjects considered the problem unsolvable within today's physics and all but one thought the problem still meaningful, though none were optimistic about a solution. The one subject who dismissed the problem had the lowest imagery frequency score, and there was also a significant rank order correlation (r = 0.83, p < .02) between degree of belief in problem unsolvability (extended to include viewing the problem as meaningful and not already solved) and a composite imagery frequency/vividness score, though the sample was too small to control for some possible confounding factors. (shrink)

It has been repeatedly suggested that synesthesia is intricately connected with unusual ways of exercising one’s mental imagery, although it is not always entirely clear what the exact connection is. My aim is to show that all forms of synesthesia are forms of (often very different kinds of) mental imagery and, further, if we consider synesthesia to be a form of mental imagery, we get significant explanatory benefits, especially concerning less central cases of synesthesia where the inducer (...) is not sensory stimulation. (shrink)

Mental images, or envisioning things with your "mind's eye," are now studied via multiple levels of observation and involve computational neuroscience, robotics and many disciplines that complement philosophy and form integral parts of cognitive science. MENTAL IMAGERY AND CREATIVITY offers an historical analysis of the use of "mental images" in science. This book also gives many useful illustrations, depicting roles of imagery with 21st century technology, including the usage of imagery, fMRIs and internet connections, allowing people to (...) control virtual avatars or robots at remote distances. Imagery formations and brain imaging techniques allow non-communicative patients, who appear to be in vegetative states, to communicate effectively, despite brain damage. Notwithstanding many 21st century developments of imagery combined with technology and science, many speculative accounts of imagery arose in the 20th century. Philosophic developments, regarding the relation between mental imagery and creativity, are provided in order to compare and contrast speculative and rational foundations. Creativity is defined in relation to problem-solving, inventiveness, art, discovery and cognitive formations of ranges of possibilities, arising before and after realizations (i.e., when one recognizes real and unreal events or solutions), involving images of events, solutions and alternatives. (shrink)

It is clear that visual imagery is somehow significantly visual. Some theorists, like Kosslyn, claim that the visual nature of visualisations derives from features of the neural processes which underlie those episodes. Pylyshyn claims, however, that it may merely reflect special features of the contents which we grasp when we visualise things. This paper discusses and rejects Pylyshyn's own attempts to identify the respects in which the contents of visualisations are notably visual. It then offers a novel and very (...) different account of what is distinctively sensory about the contents of sensory images. The paper's alternative account is used in explaining various pieces of phenomenological and behavioural data concerning visualisation. Finally, it is tentatively suggested that the proposed account of the contents of sensory images may also shed light upon some of the neurological data involving visualisation and sensory imagery more generally. (shrink)

Unconscious logical inference seems to rely on the syntactic structures of mental representations (Quilty-Dunn & Mandelbaum 2018). Other transitions, such as transitions using iconic representations and associative transitions, are harder to assimilate to syntax-based theories. Here we tackle these difficulties head on in the interest of a fuller taxonomy of mental transitions. Along the way we discuss how icons can be compositional without having constituent structure, and expand and defend the “symmetry condition” on Associationism (the idea that associative links and (...) transitions are perfectly symmetric). In the end, we show how a BIT (“bare inferential transition”) theory can cohabitate with these other non-inferential mental transitions. (shrink)

Aphantasia is a condition that is often characterized as the impaired ability to create voluntary mental images. Aphantasia is assumed to selectively affect voluntary imagery mainly because even though aphantasics report being unable to visualize something at will, many report having visual dreams. We argue that this common characterization of aphantasia is incorrect. Studies on aphantasia are often not clear about whether they are assessing voluntary or involuntary imagery, but some studies show that several forms of involuntary (...) class='Hi'>imagery are also affected in aphantasia (including imagery in dreams). We also raise problems for two attempts to show that involuntary images are preserved in aphantasia. In addition, we report the results of a study about afterimages in aphantasia, which suggest that these tend to be less intense in aphantasics than in controls. Involuntary imagery is often treated as a unitary kind that is either present or absent in aphantasia. We suggest that this approach is mistaken and that we should look at different types of involuntary imagery case by case. Doing so reveals no evidence of preserved involuntary imagery in aphantasia. We suggest that a broader characterization of aphantasia, as a deficit in forming mental imagery, whether voluntary or not, is more appropriate. Characterizing aphantasia as a volitional deficit is likely to lead researchers to give incorrect explanations for aphantasia, and to look for the wrong mechanisms underlying it. (shrink)

Human beings have the ability to ‘augment’ reality by superimposing mental imagery on the visually perceived scene. For example, when deciding how to arrange furniture in a new home, one might project the image of an armchair into an empty corner or the image of a painting onto a wall. The experience of noticing a constellation in the sky at night is also perceptual-imaginative amalgam: it involves both seeing the stars in the constellation and imagining the lines that connect (...) them at the same time. I here refer to such hybrid experiences – involving both a bottom-up, externally generated component and a top-down, internally generated component – as make-perceive (Briscoe 2008, 2011). My discussion in this paper has two parts. In the first part, I show that make-perceive enables human beings to solve certain problems and pursue certain projects more effectively than bottom-up perceiving or top-down visualization alone. To this end, the skillful use of projected mental imagery is surveyed in a variety of contexts, including action planning, the interpretation of static mechanical diagrams, and non-instrumental navigation. In the second part, I address the question of whether make-perceive may help to account for the “phenomenal presence” of occluded or otherwise hidden features of perceived objects. I argue that phenomenal presence is not well explained by the hypothesis that hidden features are represented using projected mental images. In defending this position, I point to important phenomenological and functional differences between the way hidden object features are represented respectively in mental imagery and amodal completion. (shrink)

Nanay (2017) argues for unconscious mental imagery, inter alia based on the assumption that successful performance in imagery tasks requires the manipulation of mental imagery. I challenge this assumption with the help of results presented in Shepard and Metzler (1971), Zeman et al. (2010), and Keogh and Pearson (2018). The studies suggest that imagery tasks can be successfully performed by means of cognitive/propositional strategies which do not rely on imagery.

Mental imagery is early perceptual processing that is not triggered by corresponding sensory stimulation in the relevant sense modality. Multimodal mental imagery is early perceptual processing that is triggered by sensory stimulation in a different sense modality. For example, when early visual or tactile processing is triggered by auditory sensory stimulation, this amounts to multimodal mental imagery. Pulling together philosophy, psychology and neuroscience, I will argue in this paper that multimodal mental imagery plays a crucial role (...) in our engagement with musical works. Engagement with musical works is normally a multimodal phenomenon, where we get input from a number of sense modalities. But even if we screen out any input that is not auditory, multimodal mental imagery will still play an important role that musicians and composers often actively rely on. (shrink)

Do frogs have lips? In thinking of an answer to this question, many people form a mental image of a frog and scrutinise it to find the answer. But what are they doing when they do this? The imagery debate that Michael Tye addresses in this book is between two kinds of answer to this question: the "pictorialist" answer that images are in important ways like pictures, and the "descriptionalist" answer that they are more like descriptions. Versions of these (...) views have been held both by philosophers and psychologists. Tye's book aims to disentangle the various claims made by pictorialists and descriptionalists and to defend a theory which incorporates elements from the description and picture theories. (shrink)

Bayesian classifiers perform well when each of the features is completely independent of the other which is not always valid in real world applications. The aim of this study is to implement and compare the performances of each variant of the Bayesian classifier (Multinomial, Bernoulli, and Gaussian) on anomaly detection in network intrusion, and to investigate whether there is any association between each variant’s assumption and their performance. Our investigation showed that each variant of the Bayesian algorithm blindly follows its (...) assumption regardless of feature property, and that the assumption is the single most important factor that influences their accuracy. Experimental results show that Bernoulli has accuracy of 69.9% test (71% train), Multinomial has accuracy of 31.2% test (31.2% train), while Gaussian has an accuracy of 81.69% test (82.84% train). Going deeper, we investigated and found that each Naïve Bayes variants performances and accuracy is largely due to each classifier assumption, Gaussian classifier performed best on anomaly detection due to its assumption that features follow normal distributions which are continuous, while multinomial classifier have a dismal performance as it simply assumes discreet and multinomial distribution. (shrink)

The relationship between perceptual experience and memory can seem to pose a chal- lenge for conceptualism, the thesis that perceptual experiences require the actualization of conceptual capacities. Since subjects can recall features of past experiences for which they lacked corresponding concepts at the time of the original experience, it would seem that a subject’s conceptual capacities do not impose a limit on what he or she can experience perceptually. But this conclusion ignores the fact that concepts can be composed of (...) other simpler concepts that a subject possessed earlier, and that de- monstrative capacities can explain how a subject can experience a particular feature of her environment, even when she lacks a fully general concept for that feature. Using these resources, conceptualism can explain the relation between perceptual experience and memory. Nevertheless, a puzzle remains for the defender of conceptualism. A cer- tain view about the relation between perceptual experience and mental imagery in epi- sodic memory – that imagery in recall matches the experience retained in it – can make it difficult to understand how conceptualism could be true. For if a subject’s conceptual capacities determine what the phenomenology of an experience (or memory of it) is like, then one would expect a perceptual experience and its recall in memory to differ in phenomenology if they involve different concepts. In this essay, I solve this puzzle for conceptualism by undermining the assumption that there is a match between im- agery in episodic memory and the phenomenal character of experience. (shrink)

Traditionally, the “Imagery Debate” has opposed two main camps: depictivism and descriptivism. This debate has essentially focused on the nature of the internal representations thought to be involved in imagery, without addressing at all the question of action. More recently, a third, “embodied” view is moving the debate into a new phase. The embodied approach focuses on the interdependence of perception, cognition and action, and in its more radical line this approach promotes the idea that perception is not (...) a process involving internal world-models. The anti-representationalist version of the embodied paradigm covers, among others that we shall not discuss here, two quite different positions, namely the enactive approach and sensorimotor theory. Up to now these two anti-representationalist accounts have generally been confounded. In this paper we will argue that despite some important commonalities, enactive and sensorimotor accounts come with distinctive theoretical traits with regard to their approach to imagery. These become manifest when critically examining the role they assign to sensorimotor engagements with the world. We shall argue that enactive and sensorimotor approaches are different in their understanding of the role of embodied action, and these different notions of embodiment lead to different explanatory accounts of perception and imagery. We propose that, due to existing ambiguities in enactivism, the sensorimotor theory is a better framework for a skill-based approach to imagery. (shrink)

When we see an object, we also represent those parts of it that are not visible. The question is how we represent them: this is the problem of amodal perception. I will consider three possible accounts: (a) we see them, (b) we have non-perceptual beliefs about them and (c) we have immediate perceptual access to them, and point out that all of these views face both empirical and conceptual objections. I suggest and defend a fourth account, according to which we (...) represent the occluded parts of perceived objects by means of mental imagery. This conclusion could be thought of as a (weak) version of the Strawsonian dictum, according to which “imagination is a necessary ingredient of perception itself”. (shrink)

The aim of this paper is to argue that the phenomenal similarity between perceiving and visualizing can be explained by the similarity between the structure of the content of these two different mental states. And this puts important constraints on how we should think about perceptual content and the content of mental imagery.

Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is significant overlap between the perceptual and imaginative domains. The current evidence, however, is inconclusive: while evidence from transcranial brain stimulation seems to support this conclusion, neurophysiological evidence from brain lesion studies (e.g., from patients with brain lesions resulting in a loss of mental imagery but not a corresponding loss of perception and vice versa) indicates that there are (...) functional and anatomical dissociations between mental imagery and perception. Assuming that the mental imagery and perception do not overlap, at least, to the extent traditionally assumed, then the question arises as to what exactly mental imagery is and whether it parallels perception by proceeding via several functionally distinct mechanisms. In this review, we argue that even though there may not be a shared mechanism underlying vision for perception and conscious imagery, there is an overlap between the mechanisms underlying vision for action and unconscious visual imagery. On the basis of these findings, we propose a modification of Kosslyn’s model of imagery that accommodates unconscious imagination and explore possible explanations of the quasi-pictorial phenomenology of conscious visual imagery in light of the fact that its underlying neural substrates and mechanisms typically are distinct from those of visual experience. (shrink)

In this paper, I oppose the common assumption that visual descriptions in prose fiction are imageable by virtue of perceptual mimesis. Based on introspection as well as convergent support from cognitive science and other disciplines, I argue that visual description (and the mental imagery it elicits), unlike narrative (and the mental imagery it elicits), often stands in no positive relation to perceptual mimesis because it lacks a structural counterpart in perceptual experience. I present an alternative way of defining (...) the kind of mental imagery elicited by visual descriptions, and propose a number of text variables underlying the imageability or non-imageability of any such description. (shrink)

It has been suggested that certain problems may be unsolvable because of the mind's cognitive structure, but we may wonder what problems, and exactly why. The ultimate origin of the universe and the mind-body problem seem to be two such problems. As to why, Colin McGinn has argued that the mind-body problem is unsolvable because any theoretical concepts about the brain will be observation-based and unable to connect to unobservable subjective experience. McGinn's argument suggests a requirement of imagability -- an (...) observation basis -- for physical causal explanation that cannot be met for either of these problems. Acausal descriptions may be possible but not the causal analyses that provide the greatest explanatory satisfaction, a psychological phenomenon that seems tied to the strength of the underlying observation basis but is affected by other factors as well. (shrink)

The influence of imagery on perception depends on the content of the mental image. Sixty-three students responded to the location of the 2 hands of a clock while visualizing the correct or an incorrect clock. Reaction time was shorter with valid cueing. Could this have resulted from visual acquisition strategies such as planning visual saccades or shifting covert attention? No. in this study, a crucial control condition made participants look at rather than visualize the cue. Acquisition strategies should have (...) affected equally both types of cueing, but we observed that the effect of the visual cue was smaller and limited to a particular subcase in which one expects visual acquisition strategies. Thus, what matters is the similarity of the content of the mental image with the visual scene. In addition, an interaction involving the hand used for responding supports the notion that composite imagery is lateralized. (shrink)

We present a colorful and novel discussion of mathematical techniques of visualizing a fourth spatial dimension. We first discuss notions of dimensionality including the homotopy dimension for objects in an (infinity,1)-topos. We try to visualize the fourth spatial dimension using color, and illustrate this with four-dimensional ice-cream. We apply categorical negative thinking to what we have called (infinity,1)-visual epistemology. The aim is that visualizations of higher spatial dimensions can occur functorially. We illustrate with five images five conjectural methods for how (...) to visualize the fourth spatial dimension. (shrink)

How does visual imagination differ from visual perceptual experience? And how should we describe experiences of visual imagery? Moreover how can people who have visual imagery convey what it is like to have it to those who have never had it – congenital aphantisics? This paper addresses these questions using examples of illusions and other perceptual phenomena to hone in on the answers.

I articulate and defend a principle governing enforcement rights in response to a non‐culpable non‐just rights‐intrusion (e.g., wrongful bodily attack by someone who falsely, but with full epistemic justification, believes that he is acting permissibly). The account requires that the use of force reduce the harm from such intrusions and is sensitive to the extent to which the intruder is agent‐responsible for imposing intrusion‐harm.