This article discusses the reasons why illusory contours are likely to result from adaptive perceptual mechanisms that have evolved across species to promote behavioral success.

There is a continuing debate in the field of perceptual organization as to whether the locus of global processing is early or late perceptual, as previous studies have yielded contrary results. The conducted behavioural study explored this issue with the paradigm of collating global processing with other process of perceptual organization, namely illusory contours processing. Interaction between these two processes of perceptual organization would indicate that global processing has an early perceptual locus, whereas the lack of such interaction (...) would suggest the late perceptual locus of global processing. In experiment 1, the effect of global dominance was obtained with the use of a compound figure composed of geometrical shapes with real edges. Results showed that the processing of the figure at the global level was faster and that it disrupted the processing of the figures from the local level. In experiment 1b, the compound figure was composed of local geometrical shapes generated with the use of the line-end induced illusory contours. Local elements with illusory contours did not affect the processing of the hierarchical structure and the effect of global precedence occurred without any changes. In experiment 2a, a global advantaged effect within a compound figure with local elements with real edges was obtained in the paradigm of attention divided between levels of the hierarchical structure. When illusory contours of local elements of a compound figure were introduced to this paradigm, this again had no effect on the perceptual global advantage. The results demonstrate the lack of interaction between global processing and illusory contour processing, indicating that the locus of global processing is rather late perceptual. (shrink)

Results from three experiments using spatial forced-choice techniques show that an illusory contour improves the detectability of a spatially superimposed, 1pixel-thin subthreshold line of either contrast polarity. Furthermore, the subthreshold line is found to enhance the visibility of an illusory contour bridging the gap between the two colinear edges of physically defined boundaries. Stimuli which do not induce illusory contours, but reduce uncertainty about the spatial position of the line, give rise to a slight detection facilitation, (...) but the threshold of 75% correct responses is not attained. The data indicate that superimposing illusory contours and 1pixel thin subthreshold lines produces interactions which are similar to classic subthreshold summation. This provides psychophysical evidence for the functional equivalence of illusory and real lines, as suggested by neurophysiological data from single-cell recordings in V1 and V2 of cats and primates. (shrink)

Light increment thresholds were measured on either side of one of the illusory contours of a white-on-black Kanizsa square and on the illusory contour itself. The data show that thresholds are elevated when measured on either side of the illusory border. These elevations diminish with increasing distance of the target spot from the white elements which induce the illusory figure. The most striking result, however, is that threshold elevations are considerably lower or even absent when (...) the target is located on the illusory contour itself. At an equivalent position in a control figure where no illusory contour is visible, such a threshold decrease does not occur. The present observations add empirical support to neural theories of illusory form perception. (shrink)

The perceived strength of darkness enhancement in the centre of surfaces surrounded or not surrounded by illusory contours was investigated as a function of proximity of the constituent elements of the display and their angular size. Magnitude estimation was used to measure the perception of the darkness phenomenon in white-on-grey stimuli. Darkness enhancement was perceived in both types of the stimuli used, but more strongly in the presence of illusory contours. In both cases, perceived darkness enhancement (...) increased with increasing proximity of the constituent parts of the display and with their angular size. These results suggest that the occurrence of darkness (or brightness) enhancement phenomena in the centre of the displays is not directly related to illusory contours, which only reinforce the subjective surface brightness/darkness. (shrink)

This article introduces an experimental paradigm to selectively probe the multiple levels of visual processing that influence the formation of object contours, perceptual boundaries, and illusory contours. The experiments test the assumption that, to integrate contour information across space and contrast sign, a spatially short-range filtering process that is sensitive to contrast polarity inputs to a spatially long-range grouping process that pools signals from opposite contrast polarities. The stimuli consisted of thin subthreshold lines, flashed upon gaps between (...) collinear inducers which potentially enable the formation of illusory contours. The subthreshold lines were composed of one or more segments with opposite contrast polarities. The polarity nearest to the inducers was varied to differentially excite the short-range filtering process. The experimental results are consistent with neurophysiological evidence for cortical mechanisms of contour processing and with the Boundary Contour System model, which identifies the short-range filtering process with cortical simple cells, and the long-range grouping process with cortical bipole cells. (shrink)

Detection thresholds for a small light spot were measured at various distances from the colinear inucer edges of white inducing elements on a dark background. The data show that thresholds are elevated when the target is located close to one or more inducing element(s). Threshold elevations diminish with increasing distance of the target from colinear edges and decreasing surface size of the inducing elements. gradients show the same tendencies. Tbe present observations add empirical support to the idea that illusory (...) figures are determined by local mechanisms that operate at early stages of perceptual information processing and decision. (shrink)

We present a neuro-geometrical model for generating the shape of Kanizsa's modal subjective contours which is based on the functional architecture of the primary areas of the visual cortex. We focus on V1 and its pinwheel structure and model it as a discrete approximation of a continuous fibration π: R × P → P with base space the space of the retina R and fiber the projective line P of the orientations of the plane. The horizontal cortico-cortical connections of (...) V1 implement what the geometers call the contact structure of the fibration π, and defines therefore an integrability condition which can be shown to correspond to Field's, Hayes', and Hess' psychophysical concept of association field. We present then a variational model of curved modal illusory contours based on the idea that virtual contours are “geodetic” integral curves of the contact structure. (shrink)

The perception of brightness differences in Ehrenstein figures and of illusory contours in phase-shifted line gratings was investigated as a function of the contrast polarity of the inducing elements. We presented either continuous lines or line-like arrangements composed of aligned dashes or dots whose spacing was varied. A yes/no procedure was used in which naive observers had to decide whether or not they perceived a brightness difference in a given Ehrenstein figure or an illusory contour in a (...) phase-shifted line grating. The results show that brightness differences are perceived to some extent in Ehrenstein figures with inducers of opposite polarity of contrast; however, the percentage of yes response was systematically lower and response times were longer than for figures with inducers of the same polarity. Phase-shifted line gratings with lines of opposite polarity of contrast yielded stronger illusory contours and shorter response times than those with lines of the same polarity. When the sign of contrast was not the same within a given line of induction, neither differences in brightness nor illusory contours were perceived. The results suggest that the mechanisms that lead to apparent differences in brightness are more sensitive to input of the same contrast polarity, the mechanisms generating illusory contours more sensitive to input of opposite polarity. The data are discussed in the light of a multistage approach to illusory form perception and some implications for cortical models of illusory contour integration are discussed. (shrink)

Contour adaptation is a recently described paradigm that renders otherwise salient visual stimuli temporarily perceptually invisible. Here we investigate whether this illusion can be exploited to study visual awareness. We found that CA can induce seconds of sustained invisibility following similarly long periods of uninterrupted adaptation. Furthermore, even fragmented adaptors are capable of producing CA, with the strength of CA increasing monotonically as the adaptors encompass a greater fraction of the stimulus outline. However, different types of adaptor patterns, such as (...) distinctive shapes or illusory contours, produce equivalent levels of CA suggesting that the main determinants of CA are low-level stimulus characteristics, with minimal modulation by higher-order visual processes. Taken together, our results indicate that CA has desirable properties for studying visual awareness, including the production of prolonged periods of perceptual dissociation from stimulation as well as parametric dependencies of that dissociation on a host of stimulus parameters. (shrink)

In visual science the term filling-inis used in different ways, which often leads to confusion. This target article presents a taxonomy of perceptual completion phenomena to organize and clarify theoretical and empirical discussion. Examples of boundary completion (illusory contours) and featural completion (color, brightness, motion, texture, and depth) are examined, and single-cell studies relevant to filling-in are reviewed and assessed. Filling-in issues must be understood in relation to theoretical issues about neuralignoring an absencejumping to a conclusionanalytic isomorphismCartesian materialism, (...) a particular neural stage that forms the immediate substrate of perceptual experience enactiveanimatesubpersonal” considerations about internal processing, but rather by considerations about the task of vision at the level of the animal or person interacting with the world. (shrink)

Representationalism emerges unscathed from Pessoa et al.'s attack. They fail to undermine a key reason for its influence: it has the theoretical resources to explain many illusory visual experiences such as illusory contours and features. Furthermore, in attempting to undermine representationalism, the authors seem to erect an unduly inflated distinction between neural accounts of perception and personal-level accounts of perception.

A fundamental characteristic of human visual perception is the ability to group together disparate elements in a scene and treat them as a single unit. The mechanisms by which humans create such groupings remain unknown, but grouping seems to play an important role in a wide variety of visual phenomena, and a good understanding of these mechanisms might provide guidance for how to improve machine vision algorithms. Here, we build on a proposal that some groupings are the result of connections (...) in cortical area V2 that join disparate elements, thereby allowing them to be selected and segmented together. In previous instantiations of this proposal, connection formation was based on the anatomy (e.g., extent) of receptive fields, which made connection formation obligatory when the stimulus conditions stimulate the corresponding receptive fields. We now propose dynamic circuits that provide greater flexibility in the formation of connections and that allow for top-down control of perceptual grouping. With computer simulations we explain how the circuits work and show how they can account for a wide variety of Gestalt principles of perceptual grouping, texture segmentation tasks, amodal illusory contours, and ratings of perceived groupings. We propose that human observers use such top-down control to implement task-dependent connection strategies that encourage particular groupings of stimulus elements in order to promote performance on various visual tasks. (shrink)

This informative and conceptually stimulating target article is very useful. I merely query whether the term “illusory contours” is appropriate for gap filling; “illusory surfaces” seems better – and “fictional surfaces” better still. These seem to be rule based rather than knowledge based, suggesting indeed the importance of distinguishing rules (analogous to syntax in language) from knowledge (equivalent to semantics) for classifying perceptual phenomena.

Often, sensory input underdetermines perception. One such example is the perception of illusory contours. In illusory contour perception, the content of the percept includes the presence of a contour that is absent from the informational content of the sensation. (By “sensation” I mean merely information-bearing events at the transducer level. I intend no further commitment such as the identification of sensations with qualia.) I call instances of perception underdetermined by sensation “underdetermined perception.” The perception of illusory (...) contours is just one kind of underdetermined perception. The focus of this chapter is another kind of underdetermined perception: what I shall call "active perception". Active perception occurs in cases in which the percept, while underdetermined by sensation, is determined by a combination of sensation and action. The phenomenon of active perception has been used by several to argue against the positing of representations in explanations of sensory experience, either by arguing that no representations need be posited or that far fewer than previously thought need be posited. Such views include, but are not limited to those of Gibson (1966, 1986), Churchland. (shrink)

Integration information theories posit that the integration of information is necessary and/or sufficient for consciousness. In this paper, we focus on three of the most prominent information integration theories: Information Integration Theory, Global Workspace Theory, and Attended Intermediate-Level Theory. We begin by explicating each theory and key concepts they utilize. We then argue that the current evidence indicates that the integration of information is neither necessary nor sufficient for consciousness. Unlike GWT and AIR, IIT maintains that conscious experience is both (...) necessary and sufficient for consciousness. We present empirical evidence indicating that simple features are experienced in the absence of feature integration and argue that it challenges IIT’s necessity claim. In addition, we challenge IIT’s sufficiency claim by presenting evidence from hemineglect cases and amodal completion indicating that contents may be integrated and yet fail to give rise to subjective experience. Moreover, we present empirical evidence from subjects with frontal lesions who are unable to carry out simple instructions and argue that they are irreconcilable with GWT. Lastly, we argue that empirical evidence indicating that patients with visual agnosia fail to identify objects they report being conscious of present a challenge to AIR’s necessity claim. (shrink)

The troubles of our time have many causes, economic, political, cultural. All are intimately connected. Of the cultural causes, one of the most important has been disillusionment about human nature. The old view which exalted man to something a little lower than the angels has given way in many quarters to the conviction that in essentials he is no higher than the beasts, and that anyhow the very notion that anything can be ethically higher than anything else is illusory. (...) I believe that in each of these attitudes to human nature there is a distorted half-truth, in both a blindness to the half-truth of the other. In this essay I shall try to map out the main contours of human nature, so as to emphasize that, although man is at bottom identical with the beasts, he is also in a limited but all-important manner unique. I shall also argue that one consequence of his uniqueness is moral experience, and that in human nature properly understood, a moral goal is very clearly revealed. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Fictions of Discourse: Reading Narrative TheoryCarol S. GouldFictions of Discourse: Reading Narrative Theory, by Patrick O’Neill; x & 188 pp. Toronto: University of Toronto Press, 1994, $35.00 paper.Patrick O’Neill serves up a rich stew of narratology, reader-reception theory, and a postmodern theory of truth. Many narratologists have taken the postmodern turn, while others have pursued a reception-theory route. Either path requires careful navigation, and the combined one even (...) more so. Classical narratology focuses on the textual structure with its network of various narratological relations. Reader-reception theory assigns to the reader a leading role in the creation of the text. O’Neill in various ways challenges or at least reformulates the notions of both text and reader, endorsing as he does a postmodern theory of truth which he terms the “Zeno Principle.” This principle is that “narrative discourse is always potentially subversive of the story it would seem to reconstruct” (p. 7). The Zeno Principle is a version of what he understands to be the Heisenberg Principle, namely that “discourse (including theoretical discourse) at least potentially subverts the story it sets out to narrate, and ultimately itself also” (p. 9). O’Neill contends that his narratological project will support the Zeno Principle. If successful, though, his endeavor will of course meet the usual self-destructive fate of such theories. But its self-annihilation seems not to discourage O’Neill, who finds all theories essentially “ludic.” O’Neill’s undertaking is ambitious; I shall focus on just a few of his moves.First of all, it is no surprise to hear that postmodernism is not new nor even that it has a classical pedigree. But it will probably astound—not to say sadden—the reader to see O’Neill locate its origins in the paradoxes of Zeno—the fifth-century Eleatic, the logician so well known for defending the epistemic primacy of reason, one of the uncontested intellectual progenitors of Plato, who remains the explicit target of Derridean fire. This is not simply a persnickety objection to O’Neill’s terminology, but a reflection on the broad implications he draws from his narratological investigations.Plato, working in the Eleatic (Zenoian) tradition, draws our attention to the perspectival nature of literature and would extend this to all empirical discourse. Any empirical narrative—history, biography, or literature—is in principle illusory because merely perspectival. Plato, true intellectual heir of Zeno, anticipates the narratological enterprise in this respect, while demonstrating [End Page 532] the exclusive epistemic integrity of logical thought. One finds this of course in his Republic, but nowhere are his narratological sympathies more evident than in the Symposium, with its many tiers of narration. He prefigures, then, the modern insight that all narrative is, in Wayne Booth’s terms, rhetoric and in narratological terms, focalized.If we grant with Zeno, Plato, and other friends of rationality that empirical discourse is perspectival or focalized, we can see that narrative must place us in some hypothetical vantage point: from another standpoint, the world looks different and assumes new contours and mood. Once we acknowledge that no one point of view is more privileged than another, our perceptions seem less stable. Lolita, for example, told from the viewpoint of the nymphet herself, would be a different story. Moreover, any narrative must be mediated by narrative perspective, and as O’Neill indicates, the narrative vantage point may not be that of the narrator or implied author. As he puts it, “Voice and vision... [may] derive from separate points of origin” (p. 84).In a sense, then, all empirical discourse is subversive. But does it follow that all theoretical discourse is therefore subversive? O’Neill scrutinizes fictional discourse, and helpfully so for us. But the perspectival nature of literary or empirical narrative hardly suffices to cast doubt on the notion of truth per se. The real Zeno Principle is the Platonic one that however arbitrarily empirical perspective might shift, rational intuition does not. If one wants to challenge that view, one must defend the Protagoras Principle, the true classical articulation of postmodernism. Aristotle, after all, wrestles with this in his Metaphysics rather than in his Poetics.O’Neill... (shrink)

Mental capacities for perceiving, remembering, thinking, and planning involve the processing of structured mental representations. A compositional semantics of such representations would explain how the content of any given representation is determined by the contents of its constituents and their mode of combination. While many have argued that semantic theories of mental representations would have broad value for understanding the mind, there have been few attempts to develop such theories in a systematic and empirically constrained way. This paper contributes to (...) that end by developing a semantics for a ‘fragment’ of our mental representational system: the visual system’s representations of the bounding contours of objects. At least three distinct kinds of composition are involved in such representations: ‘concatenation’, ‘feature composition’, and ‘contour composition’. I sketch the constraints on and semantics of each of these. This account has three principal payoffs. First, it models a working framework for compositionally ascribing structure and content to perceptual representations, while highlighting core kinds of evidence that bear on such ascriptions. Second, it shows how a compositional semantics of perception can be compatible with holistic, or Gestalt, phenomena, which are often taken to show that the whole percept is ‘other than the sum of its parts’. Finally, the account illuminates the format of a key type of perceptual representation, bringing out the ways in which contour representations exhibit domain-specific form of the sort that is typical of structured icons such as diagrams and maps, in contrast to typical discursive representations of logic and language. (shrink)

In a recent article, Kim Sterelny and Philip Kitcher5 defend a version of genic selectionism and attempt to refute the criticisms I made of that doctrine. Their defense has two components. First, they find fault with the account I gave of the units-of-selection controversy-an account which uses the idea of probabilistic causality as a tool of explication. Second, they provide a positive account of their own of what that controversy concerns, one which they think allows genic selectionism to emerge as (...) a successful thesis. I believe that the position they sketch is mistaken, both in its general orientation and in its details. I believe that the Sterelny/ Kitcher position misunderstands what the biological question of the units of selection is about and that their criticisms of my own proposal are mistaken as well. (shrink)

Book Information Contours of Agency: Essays on Themes from Harry Frankfurt. Edited by Sarah Buss and Lee Overton. MIT Press. Cambridge MA. 2002. Pp. 381.

We provide a new link between deductive and probabilistic reasoning fallacies. Illusory inferences from disjunction are a broad class of deductive fallacies traditionally explained by recourse to a matching procedure that looks for content overlap between premises. In two behavioral experiments, we show that this phenomenon is instead sensitive to real-world causal dependencies and not to exact content overlap. A group of participants rated the strength of the causal dependence between pairs of sentences. This measure is a near perfect (...) predictor of fallacious reasoning by an independent group of participants in illusory inference tasks with the same materials. In light of these results, we argue that all extant accounts of these deductive fallacies require non-trivial adjustments. Crucially, these novel _indirect_ illusory inferences from disjunction bear a structural similarity to seemingly unrelated _probabilistic reasoning_ problems, in particular the conjunction fallacy from the heuristics and biases literature. This structural connection was entirely obscure in previous work on these deductive problems, due to the theoretical and empirical focus on content overlap. We argue that this structural parallelism provides arguments against the need for rich descriptions and individuating information in the conjunction fallacy, and we outline a unified theory of deductive illusory inferences from disjunction and the conjunction fallacy, in terms of Bayesian confirmation theory. (shrink)

Illusory Abiding: The Cultural Construction of the Chan Monk Zhongfeng Mingben. By Natasha Heller. Harvard East Asian Monographs, vol. 368. Cambridge, Mass.: Harvard Univ. Asia Center, Harvard Univ. Press, 2014. Pp. xiv + 471. $49.95.

In addition to their conduct, organizations can be stigmatized for conduct they did not engage in. Advancing a conceptual foundation of illusory conduct stigma, I explain how it stems from a perceptional process that is distinct from the one underlying conduct stigma. I use conspiracy theory as an illustrative source of illusory conduct stigma and explain how the former evolves in the absence of evidence, differs from an official narrative, and incorporates organizations. The study proposes that organizations are (...) likely targets when they have higher status, larger size, and recent media coverage, and the targeting is persistent when organizations are complex, diversified, and carry strong emotional appeal. Moreover, organizations are at times participants in the production, facilitation, and forbearance of illusory conduct stigma. The study contributes by explicating how organizations are affected as well as how they participate in the development and propagation of illusory conduct stigma. (shrink)

Descartes held that it is impossible to make true statements about what we perceive, but I go over alleged cases of illusory experience to show why such a skeptical conclusion (and recourse to God) is overblown. The overreaction, I contend, stems from an insufficient awareness of the habitual expectations brought to any given experience. These expectations manifest themselves in motor terms, as perception constantly prompts and updates an embodied posture of readiness for what might come next. Such habitual anticipations (...) work best when they efface themselves, so it is easy to blame perception when our expectations get frustrated. I illustrate this misdirected blame with the example of a stick partially in water: it is only because we expect the stick to be straight that its appearance as bent is deemed problematic. I thus conclude that, if we factor in the habitual interpretations operative in perception and switch to a processual view that allows practical engagement, we can deflate the worries that led Descartes to rule out perceptual truths. Distancing myself from the naïve “sign” of folk semiotics, my critique draws inspiration from the triadic semiotic model developed in some late medieval schools of Portugal. (shrink)

l argue that, contra Chalmers,a skeptical scenario involving deception is a genuine possibility,even if he is correct that simulations are real. I call this new skeptical position “Illusory World Skepticism.” Illusory World Skepticism draws from the simulation argument,together with work in physics,astrobiology, and AI,to argue that we may indeed be in an illusory world—a universe scale simulation orchestrated by a deceptive AI—the technophilosopher’s ultimate evil demon. In Section One I urge that Illusory World Skepticism is a (...) bone fide skeptical possibility. In Section Two, I explore features of quantum computation. Then, in Sections Three and Four, I draw from the discussion of quantum computation and assume that the simulation argument is correct,applying considerations from the fields of astrobiology and AI safety to illustrate that illusory world skepticism constitutes what I call “a serious epistemic threat”, a scenario that cannot be dismissed as requiring that knowledge is certainty or which seems to just depict a remote, fictional situation. (shrink)

Despite the fact about colour, that it is one of the most obvious and conspicuous features of the world, there is a vast number of different theories about colour, theories which seem to be proliferating rather than decreasing. How is it possible that there can be so much disagreement about what colours are? Is it possible that these different theorists are not talking about the same thing? Could it be that more than one of them is right? Indeed some theorists, (...) e.g. Leo M. Hurvich, D. L. McAdam and K. Nassau, say that the term ‘colour’ is used to identify a range of different properties, e.g. pigments, properties of light, and sensations. Such a view has its attractions, but it raises the question of what it is that unites these various concepts – what is it that would make them all concepts of colour? What is it that justifies using the same terms, ‘yellow’, ‘blue’, ‘pink’, mauve’, and so on?This paper aims to address this question, arguing that its answer supports the conclusion that the best theory of colour is a form of anti‐realism: the Illusory theory of colours. There are two parts to this thesis, one negative, the other positive. The negative part is that there are no colours, as they are ordinarily conceived. The positive part is that, nevertheless, the world is such that ‘it is as if there are such colours’. Such a theory has important implications. One is that it doesn’t fall neatly into the usual taxonomy of philosophical theories. In particular, it does not deserve the label ‘eliminativist’. Another is that it allows some space for the views expressed by Hurvich, McAdam and Nassau, but not quite in the sense that they intend. (shrink)

The plethora of tripartite bodies in postcommunist countries seems to suggest the emergence of an East European corporatism. Analysis of arrangements in Bulgaria, Czech Republic, Hungary, Slovakia, and Poland indicates instead the prevalence of illusory corporatism. Token negotiations, nonbinding agreements, and exclusion of the private sector demonstrate that tripartite procedures are deployed to introduce neoliberal, not social democratic, outcomes. A path-dependent argument stressing labor's weak class identity best explains these outcomes. East European labor, unlike historic Western counterparts, is marked (...) by a weak sense of class interests, disinclination to organize the private sector, and declining support from the workforce, making it unable to emerge as a strong force. It is not labor but the new elites that seek tripartism, hoping thereby to share burdens, conform to European norms, and demonstrate responsiveness to society. Formal tripartism also follows from the legacy of state socialism, giving symbolic voice to the formerly included now headed for exclusion. In the end, tripartism helps secure labor's acceptance of its own marginalization. (shrink)

According to mental model theory, illusory inferences are a class of deductions in which individuals systematically go wrong. Mental model theory explains them invoking the principle of truth, which is a tendency not to represent models that falsify the premises. In this paper we focus on the illusory problems based on conditional sentences. In three experiments, we show that: (a) rather than not representing models that falsify the conditionals, participants have a different understanding of what falsifies a conditional (...) (Experiment I); (b) specifically, participants think that a conditional with an impossible antecedent or consequent is false (Experiment 2); (c) if the domain of the conditionals in the illusory problems are expanded to show that their antecedents and consequents are possible, the participants find it easy to reach the correct conclusions (Experiment 3). According to our results, the illusory inferences based on conditional premises, differently from those based on disjunctive premises, are caused by a difference between the understanding of natural language factual conditionals and the truth table of the factual implication; the principle of truth is not necessary to explain them. (shrink)

The psychological study of reasoning with quantifiers has predominantly focused on inference patterns studied by Aristotle about two millennia ago. Modern logic has shown a wealth of inference patterns involving quantifiers that are far beyond the expressive power of Aristotelian syllogisms, and whose psychology should be explored. We bring to light a novel class of fallacious inference patterns, some of which are so attractive that they are tantamount to cognitive illusions. In tandem with recent insights from linguistics that quantifiers like (...) “some” are treated as wh-questions, these illusory inferences are predicted by the erotetic theory of reasoning, which postulates that a process akin to question asking and answering is behind human inference making. (shrink)

It has been suggested that the difference between misremembering (Orwellian) and misrepresentation (Stalinesque) models of consciousness cannot be differentiated (Dennett, 1991). According to an Orwellian account a briefly presented stimulus is seen and then forgotten; whereas, by a Stalinesque account it is never seen. At the same time, Dennett suggested a method for assessing whether an individual is conscious of something. An experiment was conducted which used the suggested method for assessing consciousness to look at Stalinesque and Orwellian distinctions. A (...) visual illusion, illusory line motion, was presented and participants were requested to make judgments that reflected what they were aware of. The participants were able to make responses indicating that they were aware of the actual stimulus in some conditions, but only of the illusion in others. This finding supports a claim that the difference between the Orwellian and Stalinesque accounts may be empirically observable, and that both types of events may occur depending on task and stimulus parameters. (shrink)

By using a provability predicate of PA, we define ThmPA(M) as the set of theorems of PA in a modelMof PA. We say a modelMof PA is (1) illusory if ThmPA(M) ⊈ ThmPA(ℕ), (2) heterodox if ThmPA(M) ⊈ TA, (3) sane ifM⊨ ConPA, and insane if it is not sane, (4) maximally sane if it is sane and ThmPA(M) ⊆ ThmPA(N) implies ThmPA(M) = ThmPA(N) for every sane modelNof PA. We firstly show thatMis heterodox if and only if it (...) is illusory, and that ThmPA(M) ∩ TA ≠ ThmPA(ℕ) for any illusory modelM. Then we show that there exists a maximally sane model, every maximally sane model satisfies ¬ConPA+ConPA, and there exists a sane model of ¬ConPA+ConPAwhich is not maximally sane. We define that an insane model is (5) illusory by nature if its every initial segment being a nonstandard model of PA is illusory, and (6) going insane suddenly if its every initial segment being a sane model of PA is not illusory. We show that there exists a model of PA which is illusory by nature, and we prove the existence of a model of PA which is going insane suddenly. (shrink)