E. J. Green

(Commentary on target article "Core Perception: Re-imagining Precocious Reasoning as Sophisticated Perceiving" by Bai, Hafri, Izard, Firestone, & Strickland.) Bai et al. claim that perceptual and core-cognitive object tracking operate according to common principles, including cohesion and spatiotemporal continuity. This claim is false: perceptual object continuity is not strictly governed by cohesion or spatiotemporal continuity. We must therefore either reject Bai et al.’s relocation of core-cognitive processes within perception or adopt more radically revisionary attitudes toward core cognition.

Perception puts us in touch with highly determinate properties of objects, such as fine‐grained color shades and detailed surface shapes. However, most of our immediate perceptual judgments concern more abstract properties, such as the property of being a dog, or of being red simpliciter. So, how does perception attune us to abstract properties despite its evident determinacy? This paper argues that perception can be sensitive to abstract properties in multiple, fundamentally different ways. We articulate a distinction between implicit and explicit perceptual abstraction and explore its ramifications for debates about the role of concepts in perception, the richness of perceptual content, and rationalist versus empiricist views of our innate representational repertoire. We also propose an empirical test for differentiating implicit from explicit perceptual abstraction. Finally, we outline a version of Conceptualism built on the implicit/explicit distinction, on which explicit perceptual abstraction involves the use of concepts, while implicit abstraction can occur non‐conceptually. We argue that this form of Conceptualism is both empirically viable and unscathed by prominent Non‐Conceptualist arguments.

How much of what we see is imagined? Perception is a constructive process, supplementing the information available in sensory inputs to build representations of the world, as when one perceives a cat behind a chain-link fence as a whole, intact object, though it produces only a fragmented image on the eye. A recent movement in cognitive science and the philosophy of mind argues that mental imagery supplies much of the material for constructing perceptual representations—filling in the missing parts of the cat, for instance. On this “Constitutive View” of imagery’s role in perception, perceptual representations routinely contain elements of mental imagery. This view rests on an expansive conception of what mental imagery is: roughly, imagery consists in perceptual processing that is not directly connected to sensory inputs. We challenge the Constitutive View. First, we argue that the expansive conception of imagery on which the view relies is problematic, for it fails to capture a unified psychological kind. We then consider whether phenomena such as perceptual completion, in which the occluded parts of the cat are “filled in,” support the Constitutive View. We argue that there is little explanatory utility in construing perceptual completion as a form of imagery. The constructive character of perception, we suggest, is best understood on its own terms, rather than by reference to imagery.

When we perceive an object, we perceive the object from a perspective. As a consequence of the perspectival nature of perception, when we perceive, say, a circular coin from different angles, there is a respect in which the coin looks circular throughout, but also a respect in which the coin's appearance changes. More generally, perception of shape and size properties has both a constant aspect—an aspect that remains stable across changes in perspective—and a perspectival aspect—an aspect that changes depending on one's perspective on the object. How should we account for the perspectival aspect of spatial perception? We present a framework within which to discuss the perspectival aspect of perception and put forward three desiderata that any account of the perspectival aspect of perception should satisfy. We discuss views on which the perspectival aspect of perception is analyzed in terms of constitutively mind‐dependent appearance properties as well as views on which the perspectival aspect of perception is analyzed in terms of representations of mind‐independent perspectival properties.

Perception puts us in touch with highly determinate properties of objects, such as fine-grained color shades and detailed surface shapes. However, most of our immediate perceptual judgments concern more abstract properties, such as the property of being a dog, or of being red simpliciter. So, how does perception attune us to abstract properties despite its evident determinacy? This paper argues that perception can be sensitive to abstract properties in multiple, fundamentally different ways. We articulate a distinction between implicit and explicit perceptual abstraction and explore its ramifications for debates about the role of concepts in perception, the richness of perceptual content, and rationalist versus empiricist views of our innate representational repertoire. We also propose an empirical test for differentiating implicit from explicit perceptual abstraction. Finally, we outline a version of Conceptualism built on the implicit/explicit distinction, on which explicit perceptual abstraction involves the use of concepts, while implicit abstraction can occur non-conceptually. We argue that this form of Conceptualism is both empirically viable and unscathed by prominent Non-Conceptualist arguments.

This chapter examines how our sense modalities interact in the perception of persistence. The chapter concentrates on two questions. The first concerns perceptual processing—do perceptual computations of object persistence ever integrate and compute over representations from more than one modality? It argues that this question should be answered affirmatively. The second question concerns perceptual experience—do experiences of object persistence ever exhibit a constitutively multisensory phenomenal character, or is the phenomenology of object persistence always uniquely associated with just one modality? The chapter argues that the available evidence underdetermines the answer to this question, but suggests ways it might be empirically resolved.

Conceptualism is the view that at least some perceptual representation is conceptual. This paper considers a prominent recent argument against Conceptualism due to Ned Block. Block’s argument appeals to patterns of color representation in infants, alleging that infants exhibit categorical perception of color while failing to deploy concepts of color categories. Accordingly, the perceptual representation of color categories in infancy must be non-conceptual. This argument is distinctive insofar as it threatens not only the view that all perception is conceptual, but also views that restrict the Conceptualist thesis to perceptual categorization. However, I contend that it fails at two stages. Block’s arguments for the perceptual representation of color categories in infancy, and against color concept deployment in infancy, are unpersuasive. Thus, Block has not vanquished Conceptualism. I draw out implications for debates about the perception-cognition border and for the question of whether explicit categorization occurs in perception.

In a companion paper (Byrne and Green 2023) we disentangled the main characterizations of naïve realism and argued that illusions provide the best proving ground for naïve realism and its main rival, representationalism. According to naïve realism, illusions never involve perceptual error. We assessed two leading attempts to explain apparent perceptual error away, from William Fish and Bill Brewer, and concluded that they fail. This paper considers another prominent attempt, from Craig French and Ian Phillips, and also sketches the case for representationalism.

It is widely thought that there are limits to how things can perceptually appear to us. For instance, nothing can appear both square and circular, or both pure red and pure blue. Adam Pautz has dubbed such constraints “laws of appearance.” But if the laws of appearance obtain, then what explains them? Here I examine the prospects for an empirical explanation of the laws of appearance. First, I challenge extant empirical explanations that appeal purely to the format of perceptual representation. I then develop a hybrid approach, on which the laws are explained not merely by format, but by two further factors: ecological constraints imposed by our environments, and computational constraints embodied by our perceptual systems. While the hybrid approach implies that the laws of appearance are contingent, I argue that this implication is empirically defensible, since even some of the most intuitively compelling laws have real-world counterexamples.

Molyneux’s question asks whether a person born blind who has learned to identify shapes by touch could, if suddenly granted sight, immediately identify shapes visually. This question has often been used to structure discussions of whether there is a “rational connection” between sight and touch—whether it is possible to rationally doubt whether the same shape properties are both seen and felt. I distinguish two questions under this general heading. The first concerns, roughly, whether the visual and haptic perception of shape is rationally connected in normally sighted perceivers. The second concerns, roughly, whether the visual and haptic perception of shape is rationally connected in all possible perceivers. I argue that real-world implementations of Molyneux’s question are irrelevant to the first question, but potentially relevant to the second. However, I also argue that the second question does not have the philosophical significance it is sometimes claimed to have. In particular, it cannot be used to adjudicate debates about whether the phenomenal character of perceptual experience is primarily determined “externally” by the worldly properties we perceive, or “internally” by physiological or functional properties of our brains.

Different authors offer subtly different characterizations of naïve realism. We disentangle the main ones and argue that illusions provide the best proving ground for naïve realism and its main rival, representationalism. According to naïve realism, illusions never involve perceptual error. We assess two leading attempts to explain apparent perceptual error away, from William Fish and Bill Brewer, and conclude that they fail. Another leading attempt is assessed in a companion paper, which also sketches an alternative representational account.

Christopher Hill's Perceptual experience is a must‐read for philosophers of mind and cognitive science. Here I consider Hill's representationalist account of spatial perception. I distinguish two theses defended in the book. The first is that perceptual experience does not represent the enduring, intrinsic properties of objects, such as intrinsic shape or size. The second is that perceptual experience does represent certain viewpoint‐dependent properties of objects—namely, Thouless properties. I argue that Hill's arguments do not establish the first thesis, and then I raise questions about the Thouless‐property view and its role in Hill's defense of representationalism.

A prominent view holds that perception and memory are distinguished at least partly by their temporal orientation: Perception functions to represent the present, while memory functions to represent the past. Call this view perceptual presentism. This chapter critically examines perceptual presentism in light of contemporary perception science. I adduce evidence for three forms of perceptual sensitivity to the past: (i) shaping perception by past stimulus exposure, (ii) recruitment of mnemonic representations in perceptual processing, and (iii) perceptual representation of present objects as possessing past properties. I argue that forms (i) and (ii) are consistent with perceptual presentism, while form (iii) poses a genuine threat to the view. While the empirical case for form (iii) remains inconclusive, I suggest that the most serious challenges to perceptual presentism derive from representations that integrate mnemonic and present-tensed elements in the performance of canonical perceptual functions, such as perceiving object continuity over time.

The ability to perceive the shapes of things as enduring through changes in how they stimulate our sense organs is vital to our sense of stability in the world. But what sort of capacity is shape constancy, and how is it reflected in perceptual experience? This paper defends a pluralist account of shape constancy: There are multiple kinds of shape constancy centered on geometrical properties at various levels of abstraction, and properties at these various levels feature in the content of perceptual experience, governing patterns of apparent shape similarity. I propose that the varieties of shape constancy are subserved by the syntactic complexity of perceptual shape representations. By assigning discrete constituents to various abstract shape parameters, these representations attune us to the preservation of certain abstract shape properties through changes in more determinate shape properties. Finally, I draw broader lessons concerning the nature and function of perceptual constancy.

“What is the structure of thought?” is as central a question as any in cognitive science. A classic answer to this question has appealed to a Language of Thought (LoT). We point to emerging research from disparate branches of the field that supports the LoT hypothesis, but also uncovers diversity in LoTs across cognitive systems, stages of development, and species. Our letter formulates open research questions for cognitive science concerning the varieties of rules and representations that underwrite various LoT-based systems and how these variations can help researchers taxonomize cognitive systems

Perceptual constancy has played a significant role in philosophy of perception. It figures in debates about direct realism, color ontology, and the minimal conditions for perceptual representation. Despite this, there is no general consensus about what constancy is. I argue that an adequate account of constancy must distinguish it from three distinct phenomena: mere sensory stability through proximal change, perceptual categorization of a distal dimension, and stability through irrelevant proximal change. Standard characterizations of constancy fall short in one or more of these respects. I develop an account of constancy that overcomes these problems. The account has two parts: an analysis of constancy mechanisms, and an analysis of the conditions under which a constancy capacity is exercised. I then employ this account to evaluate whether constancy is a necessary condition for perceptual representation, as some have conjectured. I argue that explanatory practice in perceptual psychology fails to support this view. Rather, it fits better with the weaker principle that representation requires specific tracking of a distal dimension.

Thepuzzle of cross‐modal shape experienceis the puzzle of reconciling the apparent differences between our visual and haptic experiences of shape with their apparent similarities. This paper proposes that we can resolve the cross‐modal puzzle by reflecting on another puzzle. Thepuzzle of perspectival characterchallenges us to reconcile the variability of shape experience through shifts in perspective with its constancy. An attractive approach to the latter puzzle holds that shape experience is complex, involving bothperspectivalaspects andconstantaspects. I argue here that parallel distinctions between perspectival and constant aspects of shape experience arise in sight and touch, and that perspectival aspects are modality‐specific while at least some constant aspects are constitutively multisensory. I then address a powerful challenge to the idea that aspects of spatial phenomenology are shared cross‐modally.

Perceptual representations pick out individuals and attribute properties to them. This paper considers the role of perceptual attribution in determining or guiding perceptual reference to objects. We consider three extant models of the relation between perceptual attribution and perceptual reference–all attribution guides reference, no attribution guides reference, or a privileged subset of attributions guides reference–and argue that empirical evidence undermines all three. We then defend a flexible-attributives model, on which the range of perceptual attributives used to guide reference shifts adaptively with context. This model underscores the remarkable and dynamic intelligence of our perceptual capacities. We elucidate implications of the model for the boundary between perception and propositional thought.

When we perceive an object, we perceive the object from a perspective. As a consequence of the perspectival nature of perception, when we perceive, say, a circular coin from different angles, there is a respect in which the coin looks circular throughout, but also a respect in which the coin's appearance changes. More generally, perception of shape and size properties has both a constant aspect—an aspect that remains stable across changes in perspective—and a perspectival aspect—an aspect that changes depending on one's perspective on the object. How should we account for the perspectival aspect of spatial perception? We present a framework within which to discuss the perspectival aspect of perception and put forward three desiderata that any account of the perspectival aspect of perception should satisfy. We discuss views on which the perspectival aspect of perception is analyzed in terms of constitutively mind‐dependent appearance properties as well as views on which the perspectival aspect of perception is analyzed in terms of representations of mind‐independent perspectival properties.

Cognitive scientists have long known that the modalities interact during perceptual processing. Cross-modal illusions like the ventriloquism effect show that the course of processing in one modality can alter the course of processing in another. But how do the modalities interact in the specific domain of object perception? This paper distinguishes and analyzes two kinds of multisensory interaction in object perception. First, the modalities may bind features to a single object or event. Second, the modalities may cooperate when differentiating an object or event from its surroundings. I critically evaluate evidence for various forms of multisensory binding. I then consider the case for multisensory differentiation. I argue that existing evidence for multisensory differentiation is inconclusive. I highlight ways that the issue might be empirically resolved.

We represent shape in both sight and touch, but how do these abilities relate to one another? This issue has been discussed in the context of Molyneux's question of whether someone born blind could, upon being granted sight, identify shapes visually. Some have suggested that we might look to real‐world cases of sight restoration to illuminate the relation between visual and tactual shape representations. Here, I argue that newly sighted perceivers should not be relied on in this way because they are unlikely to form the kinds of shape representations responsible for cross‐modal recognition in normally sighted perceivers. I then argue that the available evidence makes a compelling case for the type identity view, on which the visual and tactual representations responsible for cross‐modal recognition are type‐identical.

A venerable view holds that a border between perception and cognition is built into our cognitive architecture and that this imposes limits on the way information can flow between them. While the deliverances of perception are freely available for use in reasoning and inference, there are strict constraints on information flow in the opposite direction. Despite its plausibility, this approach to the perception-cognition border has faced criticism in recent years. This article develops an updated version of the architectural approach, which I call the dimension restriction hypothesis (DRH). According to DRH, perceptual processes are constrained to compute over a bounded range of dimensions, while cognitive processes are not. This view allows that perception is cognitively penetrable, but places strict limits on the varieties of penetration that can occur. The article argues that DRH enjoys both theoretical and empirical support, and also defends the view against several objections.

Objects are central in visual, auditory, and tactual perception. But what counts as a perceptual object? I address this question via a structural unity schema, which specifies how a collection of parts must be arranged to compose an object for perception. On the theory I propose, perceptual objects are composed of parts that participate in causally sustained regularities. I argue that this theory falls out of a compelling account of the function of object perception, and illustrate its applications to multisensory perception. I also argue that the account avoids problems faced by standard views of visual and auditory objects.

Many authors have posited an “object file” system, which underlies perceptual selection and tracking of objects. Several have proposed that this system internalizes principles specifying what counts as an object and relies on them during tracking. Here I consider a popular view on which the object file system is tuned to entities that satisfy principles of three-dimensionality, cohesion, and boundedness. I argue that the evidence gathered in support of this view is consistent with a more permissive view on which object files select and track according to well-known perceptual organization criteria. Further evidence supplies positive support for the permissive view.

The notion of an object file figures prominently in recent work in philosophy and cognitive science. Object files play a role in theories of singular reference, object individuation, perceptual memory, and the development of cognitive capacities. However, the philosophical literature lacks a detailed, empirically informed theory of object files. In this paper, we articulate and defend the multiple-slots view, which specifies both the format and architecture of object files. We argue that object files represent in a non-iconic, propositional format that incorporates discrete symbols for separate features. Moreover, we argue that features of separate categories are stored in separate memory slots within an object file. We supplement this view with a computational framework that characterizes how information about objects is stored and retrieved.

Many of the objects that we perceive have an important characteristic: When they move, they change shape. For instance, when you watch a person walk across a room, her body constantly deforms. I suggest that we exercise a type of perceptual constancy in response to changes of this sort, which I call structure constancy. In this paper I offer an account of structure constancy. I introduce the notion of compositional structure, and propose that structure constancy involves perceptually representing an object as retaining its compositional structure over time. I argue that compositional structure is represented in visual phenomenology, and I also assemble empirical evidence in support of the claim that compositional structure is recovered by the visual system. Finally, I draw out consequences of this account. I argue that structure constancy has implications for the predictive capacities of perception, and that the phenomenon places important constraints on viable accounts of both the format and reference frame of visual experience.