This is the Stanford Encyclopedia of Philosophy entry on the contents of perception.

Objects are central to perception and our interactions with the world. We perceive the world as parsed into discrete entities that instantiate particular properties, and these items capture our attention and shape how we interact with the environment. Recently there has been some debate about whether the sense of smell allows us to perceive odours as discrete objects, with some suggesting that olfaction is aspatial and doesn’t allow for object-individuation. This paper offers two empirically tractable criteria for assessing whether particular (...) objects are exhibited in perceptual experience— susceptibility to figure-ground segregation and perceptual constancies—and argues that these criteria are fulfilled by olfactory perception, and thus there are olfactory objects. I argue that there are, in fact, two different ways that olfaction allows for figure-ground segregation. First, I look at various Gestalt grouping principles, which are thought to govern when features are perceived as grouped into structured wholes, segregated from everything around them. I argue that these principles apply to olfactory experience, providing evidence of non-spatial figure-ground segregation. Second, I defend the contentious idea that a spatial variety of figure-ground segregation can also occur in olfaction. To see this, however, we need to look to empirical evidence showing that tactile stimulation and bodily movements play a crucial role in olfactory phenomenology. Finally, I draw on empirical evidence and olfactory phenomenology to argue that there are perceptual constancies in olfactory experience, allowing us to perceive odours as coherent objects that survive shifts in our perspectives on the world. (shrink)

Object perception deploys a suite of perceptual capacities that constrains attention, guides reidentification, subserves recognition, and anchors demonstrative thought. Objects for perception—perceptual objects—are the targets of such capacities. Characterizing perceptual objects for multisensory perception faces two puzzles. First is the diversity of objects across sensory modalities. Second is the unity of multisensory perceptual objects. This paper resolves the puzzles. Objects for perception are structured mereologically complex individuals. Perceptual objects are items that bear perceptible features and have perceptible parts arranged to (...) form a unified whole. This circumscribes the targets of object perception where neutral talk concerning intentional objects and objects of perception cannot. Nonetheless, it is more permissive than identifying perceptual objects with material bodies, which excludes too much and leans too heavily on vision. The account thus is tailored to capture the role of objects in perception beyond vision: tactual, auditory, and olfactory objects are individuals with differing structures. Its flexibility also enables the account to accommodate shared objects for multisensory perception: multisensory perceptual objects are mereologically complex individuals with hybrid structure. For instance, one can bimodally perceive a common whole with parts accessible to one but not both modalities. Each sense provides a partial perspective on a complex whole that is perceptible through the coordinated use of multiple senses. Understanding perceptual objects as structured mereologically complex individuals thus provides a theoretically useful notion of an object for multisensory perception that resolves the puzzles of diversity and of unity. (shrink)

While the objects of olfaction are intuitively individuated by reference to the ordinary objects from which they arise, this intuition does not accurately capture the complex nature of smells. Smells are neither ordinary three-dimensional objects, nor Platonic vapors, nor odors. Rather, smells are the molecular structures of chemical compounds within odor plumes. Molecular Structure Theory is offered as an account of smells, which can explain the nature of the external object of olfactory perception, what we experience as olfactory objects, and (...) what determines the olfactory quality of smells by which we can demarcate the spatiotemporal boundaries of smells. (shrink)

Olfaction represents odors, if it represents anything at all. Does olfaction also represent ordinary objects like cheese, fish and coffee-beans? Many think so. This paper argues that it does not. Instead, we should affirm an austere account of the intentional objects of olfaction: olfactory experience is about odors, not objects. Visuocentric thinking about olfaction has tempted some philosophers to say otherwise.

There is consensus within the chemosciences that olfactory perception is of the molecular structure of chemical compounds, yet within philosophical theories of smell there is little agreement about the nature of smell. The paper critically assesses the current state of debate regarding smells within philosophy in the hopes of setting it upon firm scientific footing. The theories to be covered are: Naïve Realism, Hedonic Theories, Process Theory, Odor Theories, and non-Objectivist Theories. The aforementioned theories will be evaluated based on their (...) explanations of the (a) the olfactory quality of a smell, (b) smells as distal entities, and (c) our experience of smells as intentional objects. The paper concludes with a defense of Molecular Structure Theory that demonstrating its superiority in accounting for each of these three aspects of smell. (shrink)

Quality-space theory (QST) explains the nature of the mental qualities distinctive of perceptual states by appeal to their role in perceiving. QST is typically described in terms of the mental qualities that pertain to color. Here we apply QST to the olfactory modalities. Olfaction is in various respects more complex than vision, and so provides a useful test case for QST. To determine whether QST can deal with the challenges olfaction presents, we show how a quality space (QS) could be (...) constructed relying on olfactory perceptible properties and the olfactory mental qualities then defined by appeal to that QS of olfactory perceptible properties. We also consider how to delimit the olfactory QS from other modalities. We further apply QST to the role that experience plays in refining our olfactory discriminative abilities and the occurrence of olfactory mental qualities in non-conscious olfactory states. QST is shown to be fully applicable to and useful for understanding the complex domain of olfaction. (shrink)

We perceive smells as perduring complex entities within a distal array that might be conceived of as smellscapes. However, the philosophical orthodoxy of Odor Theories has been to deny that smells are perceived as having a distal location. Recent challenges have been mounted to Odor Theories’ veracity in handling the timescale of olfactory perception, how it individuates odors as a distal entities, and their claim that olfactory perception is not spatial. The paper does not aim to dispute these criticisms. Rather, (...) what will be shown is that Molecular Structure Theory, a refinement of Odor Theory, can be further developed to handle these challenges. The theory is further refined by focusing on distal perception that requires considering the perceptual object as mereologically complex persisting odor against a background scene conceived of as a smellscape. What will be offered is an expansion of Molecular Structure Theory to account for distal smell perception within natural environments. (shrink)

Recent work in philosophy and cognitive science shows that knowledge is the norm of our social practice of assertion, in the sense that an assertion should express knowledge. But why should an assertion express knowledge? I hypothesize that an assertion should express knowledge because the point of assertion is to transmit knowledge. I present evidence supporting this hypothesis.

The philosophy of perception has been mostly focused on vision, to the detriment of other modalities like audition or olfaction. In this paper I focus on olfaction and olfactory experience, and raise the following questions: is olfaction a perceptual-representational modality? If so, what does it represent? My goal in the paper is, firstly, to provide an affirmative answer to the first question, and secondly, to argue that olfaction represents odors in the form of olfactory objects, to which olfactory qualities are (...) attributed. In order to do this I develop an empirically adequate notion of olfactory object that is sensitive to the peculiarities of olfaction, and defend it against various objections. (shrink)

Several theorists argue that one does not experience something as being at or coming from a distance or direction in olfaction. In contrast to this, I suggest that there can be a variety of spatial aspects of both synchronic and diachronic olfactory experiences, including spatial distance and direction. I emphasise, however, that these are not aspects of every olfactory experience. Thus, I suggest renouncing the widespread assumption there is a uniform account of the nature, including the spatial nature, of what (...) is experienced in olfactory experience. (shrink)

Amodal completion is the representation of those parts of the perceived object that we get no sensory stimulation from. While amodal completion is rife and plays an essential role in all sense modalities, philosophical discussions of this phenomenon have almost entirely been limited to vision. The aim of this paper is to examine in what sense we can talk about amodal completion in olfaction. We distinguish three different senses of amodal completion – spatial, temporal and feature-based completion – and argue (...) that all three are present and play a significant role in olfaction. (shrink)

The question of whether we can perceive absences, in addition to ‘positives’, has received recent attention in the literature on the nature of vision and audition. The aim is to demonstrate that there can be objectless forms of perceptual consciousness; specifically, to show that such episodes can be distinguished from those in which there is merely no perception at all. The current article explores this question for the domain of olfaction, and argues that there can be experiences of the absence (...) of odours, in addition to positive smell perception. Doing so sheds light upon the structure and spatial content of olfaction. (shrink)

Philosophical considerations regarding experiential spatial content have focused on exteroceptive sensations presenting external entities, and not on interoceptive experiences that present states of our own body. A notable example is studies on interoceptive touch, in which it is argued that interoceptive tactile experiences have rich spatial content such that tactile sensations are experienced as located in a spatial field. This paper investigates whether a similarly rich spatial content can be attributed to experiences of acute, cutaneous pain. It is argued that (...) such experiences of pain do not have field-like content, as they do not present distance relations between painful sensations. (shrink)

Most philosophers consider olfactory experiences to be very poor in comparison to other sense modalities. And because olfactory experiences seem to lack the spatial content necessary to object perception, philosophers tend to maintain that smell is purely sensational or abstract. I argue in this paper that the apparent poverty and spatial indeterminateness of odor experiences does not reflect the “subjective” or “abstract” nature of smell, but only that smell is not directed to particular things. According to the view defended in (...) this paper, odors are properties of stuffs. This view, motivated by several arguments grounded in the phenomenology of olfactory experience, explains in particular why odors appear to be located both in the air around our nose and in the objects from which they emanate. It also explains the power of smell in the task of discriminating chemical compounds. (shrink)

While there is a growing philosophical interest in analysing olfactory experiences, the mereological structure of odours considered in respect of how they are perceptually experienced has not yet been extensively investigated. The paper argues that odours are perceptually experienced as having a mereological structure, but this structure is significantly different from the spatial mereological structure of visually experienced objects. Most importantly, in the case of the olfactory part-structure, the classical weak supplementation principle is not satisfied. This thesis is justified by (...) referring to empirical results in olfactory science concerning the human ability to identify components in complex olfactory stimuli. Further, it is shown how differences between olfactory and visual mereologies may arise from the way in which these modalities represent space. (shrink)

I argue for sensory pluralism. This is the view that there are many forms of sensory interaction and unity, and no single category that classifies them all. In other words, sensory interactions do not form a single natural kind. This view suggests that how we classify sensory systems (and the experiences they generate) partly depends on our explanatory purposes. I begin with a detailed discussion of the issue as it arises for our understanding of thermal perception, followed by a general (...) account and defense of sensory pluralism. (shrink)

This chapter argues that olfactory experiences represent either everyday objects or ad hoc olfactory objects as having primitive olfactory properties, which happen to be uninstantiated. On this picture, olfactory experiences reliably misrepresent: they falsely represent everyday objects or ad hoc objects as having properties they do not have, and they misrepresent in the same way on multiple occasions. One might worry that this view is incompatible with the plausible claim that olfactory experiences at least sometimes justify true beliefs about the (...) world. This chapter argues that there is no such incompatibility. Since olfactory experiences reliably misrepresent, they can lead to true and justified beliefs about putatively smelly objects. (shrink)

The dual role of olfaction in both smelling and tasting, i.e. flavour perception, makes it an important test case for philosophical theories of sensory individuation. Indeed, the psychologist Paul Rozin claimed that olfaction is a “dual sense”, leading some scientists and philosophers to propose that we have not one, but two senses of smell: orthonasal and retronasal olfaction. In this paper I consider how best to understand Rozin’s claim, and upon what grounds one might judge there to be one or (...) two distinct olfactory modalities. I conclude that while Rozin may be right that humans have dual occurrences of an olfactory ‘sense’, the concept of a sense-modality, and hence the ‘sense’ of smell, is ambiguous between two different notions: a physiological sensory channel and an experiential modality, along the lines suggested by J. J. Gibson. Furthermore, recognising that these are complementary rather than competing conceptions of a sense-modality enables the formulation of a powerful ‘dual-concept’ framework for posing and addressing questions concerning the complex architecture of human multisensory experience. (shrink)

In the contemporary analytic discussions concerning human olfactory perception, it is commonly claimed that (1) olfactory experiences are representations having content and (2) olfactory experiences represent odours, like coffee odour or vanilla odour. However, despite these common assumptions, there seems to be an ontological controversy between two views: the first states that odours are perceptually represented as features and the second states that they are represented as objects. In this paper, I aim to systematically address the Bfeature or object^ status (...) of represented odours by concerning whether odours are represented (a) as subjects of properties, (b) as mereological wholes, and (c) entities persisting in a way characteristic for objects. I argue that olfactorily represented odours constitute a sui generis category and cannot be easily classified as objects or features. Such investigations constitute a step in establishing whether various human modalities are unified by organising the environment according to the same categories. (shrink)

Philosophical research into olfaction often focuses on its limitations. We explore instead an underappreciated capacity of the sense of smell, namely, its role in interpersonal experience. To illustrate this, we examine how smell can enable continuing connections to deceased loved ones. Understanding this phenomenon requires an appreciation of, first, how olfaction's limitations can facilitate experiences of the deceased person and, second, how olfaction enables experiences of what we refer to as the ‘olfactory air’ of a person. This way of experiencing (...) someone privileges their status as an environmentally situated human animal. (shrink)

The purpose of this paper is to demonstrate that Francis Hutcheson’s moral sense theory offers a satisfactory account of moral perception. I introduce Hutcheson’s work in §1 and indicate why the existence of a sixth sense is not implausible. I provide a summary of Robert Cowan and Robert Audi’s respective theories of evaluative perception in §2, identifying three problematic objections: the Directness Objection to Cowan’s ethical perception and the aesthetic and perceptual model objections to Audi’s moral perception. §3 examines Hutcheson’s (...) moral sense theory, focusing on his discussion of benevolence, the desire for the happiness of others. I deal with the unresolved issues in Hutcheson’s account by recourse to Charles Darwin’s evolutionary perspective on the moral sense in §4, arguing for the moral sense as the second-order faculty for judging benevolence. I return, in §5, to the objections, showing that moral sense theory solves all three problems and therefore offers a satisfactory account of moral perception. (shrink)

It is widely held that episodic memory is constitutively connected with space and time. In particular, many contend that episodic memory constitutively has spatial and/or temporal content: for instance, necessarily representing a spatial scene, or when a given event occurred, or at the very minimum that it occurred in the past. Here, I critically assess such claims. I begin with some preparatory remarks on the nature of episodic memory. I then ask: How, if at all, is episodic memory constitutively spatial? (...) And, how, if at all, is episodic memory constitutively temporal? In answer, I argue that episodic memory need not have any spatial content, nor (in any substantial sense) need it represent when its events occur, nor even that they occur in the past. Instead, only a relatively modest connection holds between episodic memory and time in virtue of the temporal structure of its objects. Finally, I critically assess whether considerations concerning the organization and encoding of episodic memory in creatures like us provide stronger reason to posit a constitutive link between our episodic memories and space or time. (shrink)

According to a common view, olfactory experiences lack well-developed spatial content. Nevertheless, there is also an important opposition to such a restricted perspective on olfactory spatiality, which claims that a view ascribing only rudimentary spatial content to olfaction arises from a narrow focus on short and passive olfactory experiences. In particular, it is claimed that due to the active and diachronic aspects of olfaction, olfactory experiences represent ‘smellscapes,’ i.e., spatially organized arrangements of odor plumes. This paper considers the thesis that (...) olfaction represents smellscapes by distinguishing weaker and stronger understandings of smellscapes. Weak smellscapes are odors standing in allocentric spatial relations, while strong smellscapes, in addition, are odors located at places having specific sizes and shapes. It is argued that only weak smellscapes are plausibly represented by human olfaction. (shrink)

The thesis that smells are objective and independent of perceivers may seem to be in tension with the phenomenon of perceptual variation. In this paper, I argue that there are principled reasons to think that perceptual variation is not a threat to objectivism about smells and is indeed integral to our perceptual relation to the objective world. I first distinguish various kinds of perceptual variation, and argue that the most challenging cases for the objectivist are those where an odourant smells (...) different in different conditions or to different perceivers but the odourant does not change, and there is neither misperception nor a simple failure to perceive a smell. I then argue that there is an independently plausible conception of olfactory experience on which even these challenging cases do not pose a threat to objectivism about smells. Following Kalderon’s work in the domain of colour perception, I argue that olfactory perception provides us with a partial perspective on the smells around us, where this perspective is constrained by the conditions of perception as well as by features of the perceiver. Within this framework, we can allow that perceivers with different sensitivities, or the same perceiver in different conditions, genuinely perceive the same objective smell even though this smell appears different to them. In turn, smells are best understood as qualitatively complex entities, different aspects of which can become perceptually available in different conditions and to different perceivers. (shrink)

According to a common opinion, human olfactory experiences are significantly different from human visual experiences. For instance, olfaction seems to have only rudimentary abilities to represent space; it is not clear whether olfactory experiences have any mereological structure; and while vision presents the world in terms of objects, it is a matter of debate whether there are olfactory object-representations. This paper argues that despite these differences visual and olfactory experiences share a hierarchical subject/property structure. Within this structure, olfactorily experienced odours (...) and visual objects have the same status: they are primary subjects which unify other represented elements into perceptual units. (shrink)

Thought: A Journal of Philosophy, EarlyView.

How should interaction between the senses affect thought about them? I try to capture some ways in which non sense-specific perception might be thought to make it impossible or pointless or explanatorily idle to distinguish between senses. This task is complicated by there being more than one view of the nature of the senses, and more than one kind of non sense-specific perception. I argue, in particular, that provided we are willing to forgo certain assumptions about, for instance, the relationship (...) between modes or kinds of experience, and about how one should count perceptual experiences at a time, at least one way of thinking about the senses survives the occurrence of various kinds of non sense-specific perception relatively unscathed. (shrink)

Many have suggested that, unlike the so-called higher-senses, the lower-senses are not capable of providing aesthetic experience. Supporting this is, what I will call, the Transparency-Exteroceptivity Argument, which says that a necessary feature for aesthetic experience is lacking in the case of the lower-senses, namely transparency/exteroceptivity. I argue, contrary to the Transparency-Exteroceptivity Argument, that olfaction can provide transparent access to the properties of particular external objects. I argue that the Transparency-Exteroceptivity Argument relies on a misleading visuocentric and unimodal view of (...) the senses, is guilty of hasty generalization, and should be rejected. (shrink)

In this paper, we outline and defend a view on which in olfactory experience we can, and often do, smell ordinary things of various kinds—for instance, cookies, coffee, and cake burnings—and the olfactory properties they have. A challenge to this view are cases of smelling in the absence of the source of a smell, such as when a fishy smell lingers after the fish is gone. Such cases, many philosophers argue, show that what we perceive in olfactory experience are odour (...) objects, and not ordinary things. On behalf of our opponent, we articulate a screening-off argument based on cases of lingering smells for the thesis that we do not smell ordinary things. We then develop an alternative account of these cases that is consistent with our view. In doing so, we call into question two claims that are typically built into the notion of an odour object. (shrink)

My general topic is whether limitations in olfaction’s conceptual and generally mental capabilities hinder its suitability for playing significant and sophisticated roles in theatrical productions of the standard narrative type. This is a big question and I only scratch the surface here. I begin with a brief look at smell’s most prominent roles in the theatre, as illustration and to evoke mood and atmosphere. Next, I consider the relation between smell and the experience of space, looking first at a kind (...) of power it has that is sometimes overlooked. Third, I examine a conundrum about what the objects we smell, as opposed to the objects we see, do and do not represent in a theatrical performance. Finally, the conundrum leads into a deeper discussion of whether scents or the objects we smell do the representing in theatre. (shrink)

In this paper, I provide an account of the spatiality of olfactory experiences in terms of topological properties. I argue that thinking of olfactory experiences as making the subject aware of topological properties enables us to address popular objections against the spatiality of smells, and it makes sense of everyday spatial olfactory phenomenology better than its competitors. I argue for this latter claim on the basis of reflection on thought experiments familiar from the philosophical literature on olfaction, as well as (...) on the basis of some empirical data about the localization of smells. I conclude by suggesting how the naïve‐topology framework could be applied in debates about the spatiality of other types of experiences. (shrink)

In the contemporary analytic discussions concerning human olfactory perception, it is commonly claimed that olfactory experiences are representations having content and olfactory experiences represent odours, like coffee odour or vanilla odour. However, despite these common assumptions, there seems to be an ontological controversy between two views: the first states that odours represented by olfaction should be characterised as features and the second states that they should be interpreted as objects. In this paper, I aim to systematically address the “feature or (...) object” status of odours by comparing their ontological characteristics to those possessed by visually represented objects and features. I argue that olfactorily represented odours constitute a sui generis ontological category which differs from the categories of visually represented entities and cannot be easily classified as objects or features. Such investigations constitute a step in establishing whether various human modalities are ontologically unified by organising the environment according to the same categories. (shrink)

The first part of this paper surveys types of olfactory art as well as some of the philosophical denials that odors and the sense of smell can be used for serious art making, raising the paradox that olfactory art seems actual, but the mainstream philosophical tradition has declared that one cannot make genuine artworks from odors. The second and third part of the paper address the primary argument against possibility of an olfactory aesthetics, namely, the claim that the human sense (...) of smell does not have sufficient cognitive capacity to support rational aesthetic discussion and judgment. The second part (The intuitive case for smell’s cognitive powers) examines and answers intuitive philosophical arguments against smell’s cognitive potential and the third part (The empirical case for the cognitive capacity of smell) first surveys evidence from the sciences that could be interpreted as supporting the negative position, before marshalling other empirical evidence in favor of smell’s cognitive powers. I conclude that on balance contemporary neuroscience and psychology support the view that the human sense of smell has the cognitive capacity to sustain rational aesthetic discussion and judgment. (shrink)

There are many accounts of representation in the philosophical literature. However, regarding olfaction, Burge’s (2010) account is widely endorsed. According to his account, perceptual representation is always of an objective reality, that is, perception represents objects as such. Many authors presuppose this account of representation and attempt to show that the olfactory system itself issues in representations of that sort. The present paper argues that this myopia is a mistake and, moreover, that the various arguments in favor of olfactory objects (...) fail. Yet, by taking seriously a minimal notion of representation, adopted from Shea (2018), we can see that the olfactory system is representational after all even if it doesn’t represent objects as such. That is, olfaction issues in minimal representations. Crucially, however, this paper will conclude with an argument to the effect that olfactory object files (objectual representations of olfactory objectual properties) are constructed by interactions between various mental systems. The claim to be defended is that objectual representations of olfactory objects are constructed when minimal olfactory content is embedded in object-files that contain other non-olfactory properties that meet Burge’s criteria for representation. Some extant work on feature-binding, attention, and object-files will be introduced to support the suggestion. (shrink)