Casey O'Callaghan

Approaches to the perception–cognition distinction tend toward two extremes. Many embrace a hard border, treating perception and cognition as mutually exclusive, non-overlapping categories. By contrast, eliminativism denies that any principled, theoretically useful distinction exists between perception and cognition. This article offers a third way, describing a principled but soft border between perception and cognition. This non-exclusive approach differentiates perception from cognition while allowing that they overlap. Because it rests on the notion of a psychological capacity, we call it the capacities approach. Perception and cognition are distinct psychological faculties, each of which comprises a collection of psychological capacities. What unifies and differentiates each such collection is the distinctive way in which its capacities are exercised. Perceptual capacities are those that can be exercised in a stimulus-dependent manner, whereas cognitive capacities are those that can be exercised in a stimulus-independent manner. Because some capacities, including those associated with approximate number, language, and imagery, can be exercised in each such manner, some capacities belong to both perception and cognition. We argue that the capacities approach offers an illuminating taxonomy and handles both the empirical facts and the tricky cases better than its rivals.

Recent science demonstrates that the senses do not act merely in parallel or in isolation from each other. Different senses interact and influence each other in ways that affect perceptual experience. But each aspect of perceptual experience might remain modality specific. One sense might causally but not constitutively impact perceptual experience that is associated with another. This chapter argues that not every perceptual experience is modality specific and not every phenomenal character on each occasion is associated with some specific modality. Thus, the phenomenal character of each perceptual episode is not exhausted by what is associated with each of the respective modalities plus what accrues from mere co-consciousness. A multimodal perceptual episode may have phenomenal features beyond those associated with the specific modalities. Perceptual experience therefore is more than minimally multimodal.

We can discern two opposing viewpoints regarding synesthesia. According to the first, it is an oddity, an outlier, or a disordered condition. According to the second, synesthesia is pervasive, driving creativity, metaphor, or language itself. I favor the first perspective, according to which cross-sensory synesthesia is an outlying condition. But the second perspective is not wholly misguided. My discussion has three lessons. First, synesthesia is just one of a variety of effects in which one sense causally impacts and reshapes experience associated with another. These effects are utterly common. However, due to their unfamiliarity and their conflict with a widespread conception of the role of the senses in perception and experience, until recently they have been surprising. Second, synesthesia nevertheless must be distinguished from other intermodal effects that lead to misperception, such as crossmodal illusions. Third, synesthesia may also be distinguished from the potentially much broader class of synesthetic effects.

This chapter argues that sounds are best conceived not as pressure waves that travel through a medium, nor as physical properties of the objects ordinarily thought to be the sources of sounds, but rather as events of a certain kind. Sounds are particular events in which a surrounding medium is disturbed or set into wavelike motion by the activities of a body or interacting bodies. This Event View of sounds provides a unified perceptual account of several pervasive sound phenomena, including transmission through barriers, constructive and destructive interference, and echoes.

This book comprises original chapters that address the central questions and issues that define the emerging philosophy of sounds and auditory perception. This work focuses upon two sets of interrelated concerns. The first is a constellation of debates concerning the ontology of sounds. What kinds of things are sounds, and what properties do sounds have? For instance, are sounds secondary qualities, physical properties, waves, or some type of event? The second is a set of questions about the contents of auditory experiences and of hearing. How are sounds experienced to be? What sorts of things and properties are experienced in auditory perception? For example, in what sense is auditory experience spatial; do we hear sources in addition to sounds; what is distinctive about musical listening; and what do we hear when we hear speech? An introductory chapter summarises many of the issues discussed, provides a summary of the contributions and shows how they are connected.

In crossmodal identification, a subject token identifies an item perceived in one sensory modality with an item perceived in another sensory modality. Does crossmodal identification always occur in cognition, or does crossmodal identification sometimes take place in perception? This paper argues that crossmodal identification occurs in cognition, and not in perception. Nevertheless, multisensory perception is not unalive to crossmodal identity. Experimental evidence demonstrates that perception is differentially sensitive to the identity of individuals presented to distinct senses. Such sensitivity enhances recognition and improves action. This approach relies on distinguishing crossmodal identification from perceiving crossmodal identity. Perception registers crossmodal identity, but crossmodal identification as such belongs to thought.

Perceptual malleability and diversity can stem from perceptual learning, expertise, genetics, disease, or accident. Perceptual malleability and diversity force us to reject the claim that perceptual capacities, perceptual experience, and perceptual content are universal across subjects and times. And it casts doubt on the presumption of a universal human perceptual nature. However, it does not directly challenge perceptual objectivity, understood as the claim that one can perceive a world of things and features that are independent from oneself and one's experiences and that could be perceived by other subjects.

Is speech special? This paper evaluates the evidence that speech perception is distinctive when compared with non-linguistic auditory perception. It addresses the phenomenology, contents, objects, and mechanisms involved in the perception of spoken language. According to the account it proposes, the capacity to perceive speech in a manner that enables understanding is an acquired perceptual skill. It involves learning to hear language-specific types of ethologically significant sounds. According to this account, the contents of perceptual experience when listening to familiar speech are of a variety that is distinctive to hearing spoken utterances. However, perceiving speech involves neither novel perceptual objects nor a unique perceptual modality. Much of what makes speech special stems from our interest in it.

Paradigms in philosophy and cognitive science until recently have treated perception in typical human beings as relatively fixed and unchanging. Recent research instead supports the claim that perception can be altered over time by training, deliberate practice or mere exposure. If so, we do not all bring to a scene the same stock of perceptual capacities, and our differences are not just deficits or superpowers. This paper describes six questions an account of perceptual learning ought to address, which pose difficult challenges to Kevin Connolly’s (2019) groundbreaking Offloading View of perceptual learning. In light of these questions, it sketches an alternative simple view according to which perceptual learning is acquiring a new or enhanced perceptual capacity in a particular way. The relevant capacity is a capacity perceptually to detect and differentiate a feature, where doing so constitutively if not wholly implicates perception. The relevant way is by means of an independently characterized learning process, rather than by adaptation, pure development, or mere accident. The perceptual change thus results from a smart process – one that is flexible, resilient, and responsive to feedback, rather than rigid, fragile and brute. Such a process can yield perceptual know-how. Thanks to perceptual learning, one comes to know how to perceive, in a sense that means being able to do so. Some specialists hone this to develop perceptual skills that are implicated in expert performance.

This paper presents an account of the senses and what differentiates them that is compatible with richly multisensory perception and consciousness. According to this proposal, senses are ways of perceiving. Each sense is a subfaculty that comprises a collection of perceptual capacities. What each sense shares and what differentiates one sense from another is the manner in which those capacities are exercised. Each way of perceiving involves a distinct type of information gathering, individuated by the information it functions to extract and the medium from which it does so. This approach distinguishes the project of characterizing and differentiating senses from that of attributing experiences to sensory modalities. Perceptual experiences are episodes in which perceptual capacities are exer- cised. Conscious perceptual episodes may be ascribed to distinct sensory modalities, according to the manners in which perceptual capacities are deployed on an occasion. According to this account, senses are not exclusive. First, their capacities may overlap. Second, perceptual episodes, including conscious experiences, may belong to multiple senses. Indeed, some episodes require the joint use of several senses. In this account, subjects have only limited first-person knowledge of the senses they employ.

We can discern two opposing viewpoints regarding synesthesia. According to the first, it is an oddity, an outlier, or a disordered condition. According to the second, synesthesia is pervasive, driving creativity, metaphor, or language itself. Which is it? Ultimately, I favor the first perspective, according to which cross-sensory synesthesia is an outlying condition. But the second perspective is not wholly misguided. My discussion has three lessons. First, synesthesia is just one of a variety of effects in which one sense modality causally impacts and reshapes experience associated with another. These effects are utterly common. However, due to their unfamiliarity, and to their conflict with a widespread conception of the role of the senses in perception and perceptual experience, until recently they have been surprising. Second, synesthesia nevertheless must be distinguished from other inter-modal effects that lead to misperception, such as crossmodal illusions. Third, synesthesia also may be distinguished from the potentially much broader class of synesthetic effects, which could be common across the population and within individuals.

Sounds are audible, and sound sources are audible. What is the audible relation between audible sounds and audible sources? Common talk and philosophy suggest three candidates. The first is that sounds audibly are properties instantiated by their sources. I argue that sounds are audible individuals and thus are not audibly instantiated by audible sources. The second is that sounds audibly are effects of their sources. I argue that auditory experience presents no compelling evidence that sounds audibly are causally related to audible sources. The third is that sounds audibly are related mereologically to their sources. I present and offer a defence of this third candidate