Edited by: Arnon Cahen, Ben Gurion University in the Negev, Israel; Michela C. Tacca, Heinrich-Heine University Düsseldorf, Germany
Reviewed by: Bence Nanay, University of Antwerp, Belgium; Sebastian Watzl, Harvard University, USA; Jack Lyons, University of Arkansas, USA
*Correspondence: Athanassios Raftopoulos, Department of Psychology, University of Cyprus, P.O. Box 20537, Nicosia, Cyprus. e-mail:
This article was submitted to Frontiers in Perception Science, a specialty of Frontiers in Psychology.
This is an open-access article distributed under the terms of the
In this paper, I examine the processes that occur in late vision and address the problem of whether late vision should be construed as a properly speaking perceptual stage, or as a thought-like discursive stage. Specifically, I argue that late vision, its (partly) conceptual nature notwithstanding, neither is constituted by nor does it implicate what I call pure thoughts, that is, propositional structures that are formed in the cognitive areas of the brain through, and participate in, discursive reasoning and inferences. At the same time, the output of late vision, namely an explicit belief concerning the identity and category membership of an object (that is, a recognitional belief) or its features, eventually enters into discursive reasoning. Using Jackendoff’s distinction between visual awareness, which characterizes perception, and visual understanding, which characterizes pure thought, I claim that the contents of late vision belong to visual awareness and not to visual understanding and that although late vision implicates beliefs, either implicit or explicit, these beliefs are hybrid visual/conceptual constructs and not pure thoughts. Distinguishing between these hybrid representations and pure thoughts and delineating the nature of the representations of late vision lays the ground for examining, among other things, the process of conceptualization that occurs in visual processing and the way concepts modulate perceptual content affecting either its representational or phenomenal character. I also do not discuss the epistemological relations between the representations of late vision and the perceptual judgments they “support” or “guide” or “render possible” or “evidence” or “entitle.” However, the specification of the epistemology of late vision lays the ground for attacking that problem as well.
In earlier work (Raftopoulos,
In this paper, I examine the processes that occur in late vision and discuss whether late vision should be construed as a perceptual stage or as a thought-like discursive stage. I argue that late vision, its (partly) conceptual nature notwithstanding, does not consist in pure thoughts, that is, propositional structures that are formed in the cognitive areas of the brain and participate in discursive reasoning and inferences. The content of the output of late vision, that is, an explicit belief concerning the identity of an object (recognitional belief), enters into discursive reasoning. Using Jackendoff’s (
In the first section, I sketch early vision. Then, I discuss late vision with an emphasis on its role in object recognition. The purpose is to examine some of the contents and processes of late vision and their timing. In the third section, I argue that late vision should be considered as a perceptual rather than as a discursive stage involving understanding, that is, a stage of thought processing involving pure thoughts and inferences from propositionally structured premises to the identity of objects. My argument is based on considerations regarding the sorts of contents and processes formed in early and late vision.
Early vision includes a feed forward sweep (FFS) in which signals are transmitted bottom-up. In visual areas (from LGN to IT) FFS lasts for about 100 ms. It also includes a stage at which lateral and recurrent processes that are restricted within the visual areas and do not involve signals from cognitive centers occur. Recurrent processing starts at about 80–100 ms and culminates at about 120–150 ms. Lamme (
By not involving signals from the cognitive areas of the brain, FFS and LRP are cognitively impenetrable/conceptually encapsulated, since the transmitting of signals within the visual system is not affected by top-down signals produced in cognitive areas. Early vision processing is not affected directly by top-down signals from cognitive states through attention – that is, attention does not affect the early visual processes although it may affect pre-perceptual and post-perceptual stages of vision. I have argued that this leads to the thesis that early vision has NCC, provided that concepts do not figure inherently in the perceptual system, a possibility that I have rejected (Raftopoulos,
The conceptually
This information reenters the extrastriate visual areas and modulates (at about 150 ms) perceptual processing facilitating the analysis of HSF, for example, by specifying certain cues in the image that might facilitate target identification (Barr,
A detailed analysis of the form that the hypothesis testing might take is provided by Kosslyn (
ERP experiments registering the time onset of various waveforms related to specific processes in the brain largely confirm this analysis. The N2 ERP component that signifies cognitively driven spatial–attentional effects on the extrastriate cortex is registered at about 170–200 ms. Thus, by 170 ms spatial attention directly modulates visual processing. However, cognitive top-down modulation of the extrastriate cortex, mainly V4, from the IT and parietal cortex is found as early as 150 ms, which, as we saw, is the first sign of the process of object identification.
Eventually there is considerable competition since only few items can enter in interactions with the higher hierarchically processing levels. Further selection becomes necessary when several stimuli reach the brain but only one response is possible. Attentional selection intervenes to resolve this competition. The selection results from the combination of bottom-up information processing with WM and long-term memory (LTM) that recover the meaning of input and relate it to the subject’s current goals. In the biased competition account of attention (Desimone and Duncan,
Recurrent interactions with areas outside the visual stream make storage in visual WM possible and give rise to GRP. In GRP, standing knowledge, that is, information stored in the synaptic weights of the neurons is activated (becoming part of WM) and modulates visual processing, which up to that point was conceptually encapsulated. Consequently, during GRP the conceptualization of perceptual content starts and the states formed during this stage have (perhaps partly) conceptual and eventually propositional contents
There are two sorts of completion. In modal completion the viewer has a distinct visual impression of a hidden contour or other hidden features even though these features are not occurrent sensory features. The perceptual system fills in the missing features, which thus become as phenomenally occurrent as the occurrent sensory features of the object. In amodal completion, one does not have a perceptual (imagination is not perception) impression of the object’s hidden features since the perceptual system does not fill in the missing features as it happens in modal perception; the hidden features are not perceptually occurrent.
There are cases of amodal perception that are purely perceptual, that is, bottom-up. In these cases, although no direct signals from the hidden features impinge on the retina (there is no local information available), the perceptual system can extract information regarding them from the global information contained in the visual scene without any cognitive involvement, as the resistance of the ensuing percepts to beliefs indicates. However, in such cases, the hidden features are not perceived. One simply has the visual impression of a single concrete object that is partially occluded and not the visual impression of various disparate image regions. Therefore, in these perceptually driven amodal completions there is no mental imagery involved, since no top-down signals from cognitive areas are required for the completion, and since the hidden features are not phenomenologically present.
There are also cases of amodal completion that are cognitively driven (Briscoe,
Before I proceed, allow me to delve on “mental imagery,” since the way it is used may cause some confusion concerning the top-down processes in late vision. Imagery is central in Kosslyn’s (
To decide the issue one should define mental imagery. Usually mental imagery is related to the mental construction of the image of an object or feature in its absence. The image formed from actual (perceptual) experience is called a percept to distinguish this image from an imagined or mental image. When a subject is asked to recall a visual object, the image formed in memory is called a mental image. The mental image is constructed via top-down processes (when, for example, subjects are presented with a lower case letter and are asked to form a mental image of the upper case letter, a task that is cognitively driven since it requires knowledge of the upper case letter), while the percept is constructed through a synergy of top-down and bottom-up processes. Thus, mental imagery is usually construed as (i) involving only top-down cognitively driven processes, and (ii) taking place in the absence of the imagined object or feature. This is how I use the term.
Kosslyn (
Mental imagery is perceptually and not propositionally coded, even though it may start with the activation of concepts in associative memory (Kosslyn,
Since late vision constitutively involves a synergy of bottom-up and top-down processing, whereas mental imagery, as I construe it, involves only top-down flow of information to early visual areas in the absence of sensory stimulation, I prefer (pace Kosslyn and Nanay) not to use “imagery” to designate the top-down activation of the visual cortex in late vision, even in those cases in which top-down processing completes hidden features of objects. Mental imagery differs from seeing in that it uses only the late processing components of the perceptual system when the early processing sensory-driven processes are unavailable (as when there is no sensory stimulation). Visual imagery activates the (inactive) visual processing areas to recreate to a certain extent a visual scene. As such, mental imagery, unlike late vision, involves only top-down processes. Although in both cases the early visual areas are reentered from signals emanating from cognitive centers, in late vision the cognitive centers are activated through bottom-up signals from the visual cortex, while in visual imagery the cognitive centers are activated in the absence of any sensory stimulation on the retina. Thus, I think that the top-down processes in late vision should be distinguished from mental imagery in that the former are essentially engaged by the existence of sensory stimuli on the retina, whereas in the latter there are no sensory stimuli.
Jackendoff (
The problem is whether object identification and C-completion that occur in late vision and are both dependent on concepts should be thought of as cases of vision or as cases of discursive understanding involving inferences. If late vision involves conceptual contents and if the role of concepts and stored knowledge consists, among other things, in providing some initial interpretation of the visual scene and in forming hypotheses about the identity of objects that are tested against perceptual information, one is tempted to say that this stage relies on inferences (this is what hypothesis testing amounts to) and, thus, differs in essence from the purely perceptual processes of early vision. Perhaps it would be better to construe late vision as a discursive stage involving thoughts, in the way of Jackson’s (
One might object that abandoning this usage of “to see” violates ordinary usage. A fundamental ingredient of visual experience consists in meaningful 3D solid objects. Adopting this proposal would mean that one should resist talking of seeing tigers and start talking about seeing viewer-centered visible surfaces. “By this criterion, much of the information we normally take to be visually conscious would not be, including the 3D shape of objects as well as their categorical identity” (Palmer,
The arguments to common language notwithstanding, I think that one should not assume either that late vision is an inferential discursive stage that constitutively involves thoughts in the capacity of premises in inferences whose conclusion is the content of the states of late vision (although implicit hypotheses play a role), or that late vision consists in discursively entertaining thoughts. The reason is twofold. First, I think that seeing an object is not the result of an inference, that is, a movement in thought from some premises to a conclusion and, thus, a discursive process, even though it involves concepts. Second, late vision is a stage in which conceptual modulation and perceptual processes form an inextricable link that differentiates late vision from discursive stages and renders it a different sort of a set of processes than understanding, even though late vision involves implicit beliefs regarding objects that guide the formation of hypotheses concerning object identity, and an explicit belief of the form “that O is F” eventually arises in the final stages of late vision. Late vision has an irreducible visual ingredient, which makes it different from discursive understanding. Before I discuss all these, let me clarify some terminological issues.
Traditionally judgments are occurrent states, whereas beliefs are dispositional states. To judge that O is F is to predicate Fness to O, while endorsing the predication (McDowell,
It follows that a belief
It is important for the discussion that follows to clarify another problem, namely, under which conditions are beliefs conscious or not. An intuitive answer is that, as a matter of course, one may entertain beliefs or judgments and use them for various purposes (for example to draw conclusions in inferences or guide actions) even though one is not conscious that one entertains these beliefs or judgments (as in the case of using implicit premises in an argument); these beliefs are implicit. Underneath this intuitive view one discerns the assumption that a state is conscious if the person who has it is conscious that she is in that state. Either that person has a second order thought that she is entertaining such a belief – that is, she has fact-awareness that she is entertaining that state – or she has a second order experience or inner sense that she is in such a state – that is, she has thing-awareness of the state – where “thing-awareness” and “fact-awareness” are used in the way Dretske (
being a certain sort of representation, it makes one aware of the properties (of x) and objects (x itself) of which it is a sensory representation…[A] certain belief is conscious, not because the believer is conscious of it (or conscious of having it), but because it is a representation that makes one conscious of the fact (that P) that it is a belief about…beliefs are conscious, not because you are conscious of them, but because, so to speak, you are conscious
Beliefs that are thought of as implicit but play a cognitive role in making a person aware of some facts or things are conscious (a first-order consciousness). Dretske does not claim that everything that happens to one when one becomes conscious of some object or event is conscious. However, a perceptual experience or a belief has to be conscious in order for a person to be made aware of things and events. I do not assess Dretske’s thesis, which is only among many views on consciousness (some of which are higher-order theories that Dretske resists), and I remain neutral as to how conscious state should be construed. By “implicit belief” I mean the belief held by a person who is not aware that she is having that belief.
My claim is that the processes in late vision are not inferential processes where “inference” is understood as discursive, that is, as a process that involves drawing propositions–conclusions from other propositions acting as premises by applying (explicitly or implicitly) inferential rules that are also represented. These inferences are distinguished from “inferences” as understood by vision scientists according to whom any transformation of signals carrying information according to some rule is a form of inference. “Every system that makes an estimate about unobserved variables based on observed variables performs inference… We refer to such inference problems that involve choosing between distinct and mutually exclusive causal structures as causal inference” (Shams and Beierholm,
I think that the states of late vision are not inferences from premises that include the contents of early vision states, even though it is usual to find claims that one infers that a tiger, for example, is present from the perceptual information retrieved from a visual scene. An inference relates some propositions in the form of premises with some other proposition, the conclusion. However, the objects and properties as they are represented in early vision do not constitute contents in the form of propositions, since they are part of the non-propositional NCC of perception. In late vision, the perceptual content is conceptualized but the conceptualization is not a kind of inference but rather the application of stored concepts to some input that enters the cognitive centers of the brain and activates concepts by matching their content. Thus, even though the states in late vision are formed through the synergy of bottom-up visual information and top-down conceptual influences, they are not inferences from perceptual content.
Late vision involves hypotheses regarding the identity of objects and their testing against the sensory information stored in iconic memory. One might think that inferences are involved since testing hypotheses is an inferential process even though it is not an inference from perceptual content to a recognitional thought. It is, rather, an argument of the form if A and B then (conclusion) C, where A and B are background assumptions and the hypothesis regarding the identity of an object respectively, and C is the set of visual features that the object is likely to have. A consists of implicit beliefs about the features of the hypothesized visual object. If C is what obtains in the visual areas, that is, if the predicted visual features match those that are stored in iconic memory then the hypothesis about the identity of the object is likely correct. However, the test basis or evidence against which these hypotheses are tested for a match, that is, the iconic information stored in the sensory visual areas, is not a set of propositions but patterns of neuronal activations whose content is non-propositional.
There is nothing inference-like in this matching. It is just a comparison between the activations of neuronal assemblies that encode the visual features in the scene and the activations of the neuronal assemblies that are activated top-down from the hypotheses. If the same assemblies are activated then there is a match. If they are not, the hypothesis fails to pass the test. This can be done through purely associational processes of the sort employed, say, in connectionist networks that process information according to rules and, thus, can be thought of as instantiating processing rules, without either representing these rules or operating on language-like symbolic representations. Since inferences are carried out through rules that are represented in the system, and operate on symbolic structures, the processing in a connectionist network does not involve inferences, although it can be described in terms of inference making. Thus, even though seeing an object in late vision involves the application of concepts that unify the appearances of the object and of its features under some category, it is not an inferential process. The processes in late vision despite their reliance on background beliefs do not entail by themselves a recognitional belief.
Spelke (
Being hardwired is another reason why perceptual processes should not be assimilated to inference making. Inferences presuppose that the subject applies explicitly or implicitly inferential rules that are represented in the subject. But the operations by means of which signals are transformed from one into the other in the visual system are not represented at all; they are just hardwired in the perceptual system. For this reason, perceptual operations should not be construed as inference rules, although they are describable in terms of inference rules.
Even if I am right that seeing in late vision is not the result of a discursive inference, it is still arguable that late vision should be better construed as a stage of discursive understanding rather than as a visual stage. If object recognition involves forming a belief about class-membership, even if the belief is not the result of an inference, why not say that recognizing an object is an experience-based belief that is a case of understanding rather than vision.
A first problem with this view is that late vision involves more than a recognitional belief. Suppose that S sees an animal and recognizes it as a tiger. In the parallel preattentive early vision, the proto-object that corresponds to the tiger is being represented amongst the other objects in the scene. The relevant activations enter the parietal and temporal lobes, and the prefrontal cortex, where the neuronal assemblies encoding the information about tigers are activated and this activation spreads through top-down signals to the visual areas of the brain where visual sensory memory stores the proto-objects extracted from the visual scene. The cells encoding the proto-object corresponding to the animal and its properties have their activations strengthened and win the competition against the assemblies encoding the proto-objects corresponding to the other objects in the scene. After a proto-object has been selected, the object recognition system forms hypotheses regarding the identity of the object. However, for the subject’s confidence to reach the threshold that will allow her to form beliefs about the identity of the object and report it, these hypotheses must be tested (Treisman,
To test these hypotheses the visual system allocates resources to features and regions that would confirm or disconfirm the hypotheses. Conceptual information about a tiger affects visual processing and after some hypothesis testing the animal is recognized as a tiger through the synergy of visual circuits and WM. At this point the explicit belief “O is F” is formed. This occurs after 300 ms, when the viewer consolidates the object in WM and identifies it with enough confidence to report it, which means that beliefs are formed at the final phases of late vision. However, semantic modulation of visual processing and the process of conceptualization that eventually leads to object recognition starts at about 130–200 ms. There is, thus, a time gap, between the onset of conceptualization and the recognition of an object, which is a prerequisite for the formation of an explicit recognitional belief.
As Treisman and Kanwisher (
The beliefs involved in late vision in the form of hypotheses are not in the stream of the perceiver’s consciousness; they are not explicit. The processing in late vision is done automatically and is outside both of the cognitive control of the viewer and of her awareness. Matching an input to a stored template is not under anyone’s cognitive control and is not a process of which one is aware; neither is the determination of the gist of a visual scene. The conceptualization of the content of perception is not under anyone’s control. Furthermore, for a thought to be conscious the person who has it must have access awareness to the contents of the thought; the perceiver reports, as it were, the content of her thoughts to herself. Thus, she must have some kind of a higher-order thought about the contents of her thought. Such a higher-order thought is not required in order to be able to recognize objects. Report awareness occurs in 500 ms, when the object has been categorized. This marks a difference between late vision and thought. Most of the contents and their transformations that occur during late vision cannot be in the realm of awareness, although the outcome of late vision is. Propositional inferences, by contrast, can be available to awareness.
A third reason why the beliefs formed in late vision are partly visual constructs and not pure thoughts is that the late stage of late vision in which explicit beliefs concerning object identity are formed constitutively involves visual circuits (that is, brain areas from LGN to IT in the ventral system). Pure thought involves primarily an amodal form of representation formed in higher centers of the brain, even though these amodal representations can trigger in a top-down manner the formation of mental images and can be triggered by sensory stimulation. The point is that amodal representations can be activated without a concomitant activation of the visual cortex (see Prinz,
The constitutive reliance of late vision on the visual circuits suggests that late vision relies on the presence of the object of perception; it cannot cease to function as a perceptual demonstrative that refers to the object of perception, as this has been individuated though the processes of early vision (Raftopoulos and Muller,
Note that the attributive and singular elements in perception correspond to the perceived objects and their properties and not to concepts concerning these objects and properties. The attributive elements (properties in perception) guide the contextual reference to particulars (the objects of perception) since the referent in a demonstrative perceptual reference is fixed through the properties of the referent as these properties are presented in perception – what I have called the non-conceptual mode of presentation of the object in perception (Raftopoulos and Muller,
The concepts that figure in perceptual beliefs in late vision need not correspond to perceptual attributives, that is, they need not be restricted to concepts that late vision employs when it takes over the mode of presentation of the perceptual content. Visual systems have perceptual attributives for features such as shape, size, spatial relations, color, motion, orientation, texture, and affordances (Pylyshyn,
I said that visual systems do not have perceptual attributives for category membership, which means that these higher-order properties cannot be visually represented; one does not perceive, say, tigerness, as Bayne (
The inextricable link between thought and perception in late vision explains the essentially contextual, in Perry’s (
Perception individuates objects in a visual scene by assigning object-files based primarily on spatio-temporal information. The perception itself has the demonstrative reference force of “that object” and, thus, perceptual objects are determined relationally (Burge,
Since recognitional beliefs rely on the presence of the object (reference to the object is fixed through a demonstrative as in “That x is F”), they are
It is sometimes argued that the main difference between thoughts and perceptions is that perceptual experiences, unlike thoughts, have a sensory quality to them (Dretske,
If the recognitional beliefs formed in late vision are not endorsed to become judgments, they are in some sense hypotheses. Suppose that upon viewing a scene containing an object O, S comes to believe that O is F. Since things may not be as they seem, S refrains from judging that O is F; S does not endorse the content of her perceptual belief. How is this recognitional belief different from the hypotheses or implicit beliefs that are constructed during the earlier stages of late vision in order to establish the identity of the object beyond the fact that the one is explicit, while the other is implicit?
In my view, the main difference consists in that the early hypotheses are tested against the iconic information stored in visual areas. This is an unconscious process that is outside the control of the viewer who is usually aware only of the content of the winner, that is, the content of the explicit recognitional belief. However, the recognitional belief of late vision must be tested against a different sort of evidence in order to become a judgment. It must be tested against other sorts of propositional structures, that is, pure beliefs in which the predicate terms function as pure attributions. The aim of the testing is to put aside various possible defeaters of the belief. For example, the viewer has to decide whether she is the victim of some hallucination, etc. The processes involved in this testing may be available to the viewer’s consciousness, they are usually under her control, and they have the form of inferences from propositional contents to propositional contents, unlike the processes in late vision. The viewer tries to determine whether she should take the content of her late vision at face value. This is why testing the recognitional belief against other pure beliefs is a discursive process that is within the space of reasons, whereas testing the implicit hypotheses to come up with a recognitional belief belongs to late vision. In this sense, the recognitional beliefs formed in late vision are at the interface between the space of reasons and the perceptual space and, thus, have a pivotal role to play in accounts of justification of perceptual judgments.
I can explain now my claim that a belief is a dispositional state as opposed to a judgment that is an occurrent state. I tried to express the thought that perception gives us a
There are two notions of belief here. The one is related to the expression of the content of a conceptual perceptual state, the recognitional belief, and the other is constitutively related to the notion of judgment. The relation of the belief in the first sense to late vision contents is not inferential. The relation of the same recognitional belief with the nexus of other beliefs is an inferential relation; if endorsed, the belief becomes a judgment. The belief is, thus, a disposition to make judgments (McDowell,
Johnston (
I do not claim that recognitional beliefs are always tested this way to become judgments. Under normal conditions they are not tested at all. One might argue, however, that the absence of testing means that the viewer thinks that there is no reason to doubt the recognitional belief, which in itself is a sort of implicit inference. Or, one might think that in these normal cases, the recognitional belief becomes automatically a judgment without any inferential involvement. Still, the distinction holds because on certain occasions the recognitional belief is inferentially tested against other beliefs in order to become a judgment and, thus, recognitional beliefs and perceptual judgments belong to different categories, the first being a state that has the potential to become a judgment, even if the potentiality is actualized on certain occasions automatically.
Nanay (
Briscoe (
If C-completion involves a pure perceptual thought about the hidden parts that results from an inference based on past experience and the current visual evidence, this is a case of visual understanding and not of visual awareness. I do not think that this possibility undermines my thesis that seeing the 3D sketch takes place in late vision. First, it is not clear whether there is empirical evidence for C-completion through pure thought and in the absence of any activation in visual areas. Second, if there are such cases, this only shows that sometimes C-completion does not occur in late vision but in discursive reasoning. Third, Briscoe’s example from which he argues that C-completion may involve a pure thought involves a picture of the backside of what looks like a horse. In this case C-completion takes the form of a pure thought that this is a horse without any visual awareness. This is clearly a case of an inference involving visual understanding that occurs in the space of reasons and not in late vision. My claim is, on the other hand, that seeing the 3D sketch is a case of C-completion that takes place in late vision and involves visual awareness. Thus, even if there are cases of C-completions through pure thoughts, there are sorts of C-completions, such as seeing the 3D sketch, that take place in late vision and are cases of visual awareness.
Consider the white surface of a wall seen in a shadow and perceived as gray. Even though the viewer knows that the gray shade is caused by the shadow cast on a white wall, the phenomenal character of her experience is that of gray. The phenomenal character of her experience of the situation dependent color property (Schellenberg,
Suppose now that one sees one’s hand moving back and forth. One sees the hand having the same size, a case of size constancy. If the constancy is due to cues that are available in the retinal image, the viewer is phenomenally aware of the same size despite differences in the viewing conditions. If size constancy is not effectuated through visual information and cognitive sources are needed, it is achieved in late vision; the viewer believes that the size is constant and has the phenomenal experience of a constant size. Should visual information be insufficient for perceptual constancies and should the non-visual information that ensures constancy be not available (as where attention is diverted elsewhere), the viewer would be aware of changes in size. This is what Epstein and Broota (
To recapitulate, in pure thought the beliefs formed result from discursive processes (which may include perceptual information cast in a propositional form) and their attributives are context free, while in late vision there are no discursive processes but only conceptually modulated visual processing and the relevant attributives are context bound. These differences result from the constitutive involvement in late vision of visual circuits, an involvement that is absent in pure thought. This view entails that in amodal completion, which is one of the processes that take place in late vision, the missing or occluded features are nor represented by pure perceptual beliefs, a view that is also supported by (partially) independent considerations offered by Nanay (
Some philosophers consider that there is a sharp distinction between vision and thought and attempt to explain various phenomena (such as modal and amodal completion, or cognitive effects on perception) either (exclusive “either…or”) as perceptual or thought-based. McPherson (
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
1 In Raftopoulos (
2 Concepts are constant, context independent, and freely repeatable elements that figure constitutively in propositional contents; they correspond to lexical items.
3 The P3 waveform is elicited about 250–600 ms and is generated in many areas in the brain and is associated with cognitive processing and the subjects’ reports. P3 may signify the consolidation of the representation of the object(s) in working memory.
4 This means that some conceptual content in late vision may not be propositionally structured, although recognitional beliefs have propositional structure. It is also possible that some states in late vision have both NCC and conceptual content. I will not elaborate on these issues here. Note that if some of the states of late vision can have conceptual contents that are not propositionally structured, my thesis that late vision does not involve inferences is strengthened because inferences relate propositional structures.
5 The view that the formation of the viewer independent representation of an object relies on object knowledge is common in theories of the formation of the 3D viewer independent representation. Biederman (
6 Briscoe’s paper analyzes Nanay’s (
7 The phenomenal/non-phenomenal distinction is orthogonal to the discussion on mental imagery since mental imagery, exactly like perception, can either be accompanied by consciousness, or it can be implicit (as in implicit perception). I wish to thank a reviewer for suggesting this.
8 Spelke echoes Rock’s (
9 In a
10 Note that Nanay (