Susanna Schellenberg

This paper responds to critical comments by Christopher Hill, Ram Neta, and Nico Orlandi on my book The Unity of Perception: Content, Consciousness, Evidence (OUP 2018). It addresses questions about why analyzing mental states in terms of capacities is more explanatory powerful than analyzing them in terms of processes. It further develops my view of functions and their relation to mental capacities. It clarifies the internalist commitments of my externalist view of content, consciousness, and evidence. The topics addressed include further the many-properties problem, the relation between what is perceived and what is represented, as well as the evidential transparency principle.

I argue that the ground of the epistemic force of perceptual states lies in properties of the perceptual capacities that constitute the relevant perceptual states. I call this view capacitivism, since the notion of a capacity is explanatorily basic: it is because a given subject is employing a mental capacity with a certain nature that her mental states have epistemic force. More specically, I argue that perceptual states have epistemic force due to being systematically linked to mind-independent, environ- mental particulars via the perceptual capacities that constitute the perceptual states. Thus, capacitivism shows how the epistemic force of experience is grounded in metaphysical facts about experience. Capacitivism is a distinctive externalist view of evidence and knowledge that does not invoke reliability, remains stead- fastly naturalistic, and in recognizing a metaphysically substantive common elem- ent between perception and hallucination avoids any commitment to disjunctivism.

Despite their importance in the history of philosophy and in particular in the work of Aristotle and Kant, mental capacities have been neglected in recent philosophical work. By contrast, the notion of a capacity is deeply entrenched in psychology and the brain sciences. Driven by the idea that a cognitive system has the capacity it does in virtue of its internal components and their organization, it is standard to appeal to capacities in cognitive psychology. The main benefit of invoking capacities in an account of the mind is that it allows for an elegant counterfactual analysis of mental states: it allows us to analyze mental states on three distinct yet interrelated levels. A first level of analysis pertains to the function of mental capacities. A second level of analysis pertains to the mental capacities employed, irrespective of the context in which they are employed. A third level of analysis pertains to the mental capacities employed, taking into account the context in which they are employed. This paper develops an account of perceptual capacities. This account involves an analysis of their function, their individuation and possession conditions, the relation between perceptual capacities and their employment, as well as their informational and neural base conditions.

Perception is our key to the world. It plays at least three different roles in our lives. It justifies beliefs and provides us with knowledge of our environment. It brings about conscious mental states. It converts informational input, such as light and sound waves, into representations of invariant features in our environment. Corresponding to these three roles, there are at least three fundamental questions that have motivated the study of perception. How does perception justify beliefs and yield knowledge of our environment? How does perception bring about conscious mental states? How does a perceptual system accomplish the feat of converting varying informational input into mental representations of invariant features in our environment? This book presents a unified account of the phenomenological and epistemological role of perception that is informed by empirical research. So it develops an account of perception that provides an answer to the first two questions, while being sensitive to scientific accounts that address the third question. The key idea is that perception is constituted by employing perceptual capacities - for example the capacity to discriminate instances of red from instances of blue. Perceptual content, consciousness, and evidence are each analyzed in terms of this basic property of perception. Employing perceptual capacities constitutes phenomenal character as well as perceptual content. The primacy of employing perceptual capacities in perception over their derivative employment in hallucination and illusion grounds the epistemic force of perceptual experience. In this way, the book provides a unified account of perceptual content, consciousness, and evidence.

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.

I argue that perceptual consciousness is constituted by a mental activity. The mental activity in question is the activity of employing perceptual capacities, such as discriminatory, selective capacities. This is a radical view, but I hope to make it plausible. In arguing for this mental activist view, I reject orthodox views on which perceptual consciousness is analyzed in terms of peculiar entities, such as, phenomenal properties, external mind-independent properties, propositions, sense-data, qualia, or intentional objects.

I argue that any account of perceptual experience should satisfy the following two desiderata. First, it should account for the particularity of perceptual experience, that is, it should account for the mind-independent object of an experience making a difference to individuating the experience. Second, it should explain the possibility that perceptual relations to distinct environments could yield subjectively indistinguishable experiences. Relational views of perceptual experience can easily satisfy the first but not the second desideratum. Representational views can easily satisfy the second but not the first desideratum. I argue that to satisfy both desiderata perceptual experience is best conceived of as fundamentally both relational and representational. I develop a view of perceptual experience that synthesizes the virtues of relationalism and representationalism, by arguing that perceptual content is constituted by potentially gappy de re modes of presentation.

How can perception yield knowledge of the world? One challenge in answering this question is that one necessarily perceives from a particular location. Thus, what is immediately perceptually available is subject to situational features, such as lighting conditions and one’s location. Nonetheless, one can perceive the shape and color of objects. My dissertation aims to provide an explanation for how this is possible. The main thesis is that giving such an explanation requires abandoning the traditional model of perception as a two-place relation between subjects and objects in favor of a model of perception as a three-place relation between subjects, objects, and situations.

I argue that perception is necessarily situation-dependent. The way an object is must not just be distinguished from the way it appears and the way it is represented, but also from the way it is presented given the situational features. First, I argue that the way an object is presented is best understood in terms of external, mind-independent, but situation-dependent properties of objects. Situation-dependent properties are exclusively sensitive to and ontologically dependent on the intrinsic properties of objects, such as their shape, size, and color, and the situational features, such as the lighting conditions and the perceiver’s location in relation to the perceived object. Second, I argue that perceiving intrinsic properties is epistemically dependent on representing situation-dependent properties. Recognizing situation-dependent properties yields four advantages. It makes it possible to embrace the motivations that lead to phenomenalism and indirect realism by recognizing that objects are presented a certain way, while holding on to the intuition that subjects directly perceive objects. Second, it acknowledges that perceptions are not just individuated by the objects they are of, but by the ways those objects are presented given the situational features. Third, it allows for a way to accommodate the fact that there is a wide range of viewing conditions or situational features that can count as normal. Finally, it makes it possible to distinguish perception and thought about the same object with regard to what is represented

I argue that any account of imagination should satisfy the following three desiderata. First, imaginations induce actions only in conjunction with beliefs about the environment of the imagining subject. Second, there is a continuum between imaginations and beliefs. Recognizing this continuum is crucial to explain the phenomenon of imaginative immersion. Third, the mental states that relate to imaginations in the way that desires relate to beliefs are a special kind of desire, namely desires to make true in fiction. These desires to make true in fiction do not differ from regular desires in kind, but only in content. I argue for these three desiderata in turn by critically discussing several recent accounts of imagination. 

I develop a view of the common factor between subjectively indistinguishable perceptions and hallucinations that avoids analyzing experiences as involving awareness relations to abstract entities, sense-data, or any other peculiar entities. The main thesis is that hallucinating subjects employ concepts (or analogous nonconceptual structures), namely the very same concepts that in a subjectively indistinguishable perception are employed as a consequence of being related to external, mind-independent objects or property-instances. These concepts and nonconceptual structures are identified with modes of presentation types. Since a hallucinating subject is not related to any such objects or property-instances, the concepts she employs remain empty. I argue that the phenomenology of hallucinations and perceptions can be identified with employing concepts and analogous nonconceptual structures. By doing so, I defend an ontologically minimalist view of the phenomenology of experience that (1) vindicates Aristotelianism about types and (2) amounts to a naturalized view of the phenomenology of experience.

Perceptions guide our actions and provide us with evidence of the world around us. Illusions and hallucinations can mislead us: they may prompt as to act in ways that do not mesh with the world around us and they may lead us to form false beliefs about that world. The capacity view provides an account of evidence that does justice to these two facts. It shows in virtue of what illusions and hallucinations mislead us and prompt us to act. Moreover, it shows in virtue of what we are in a better epistemic position when we perceive than when we hallucination. In this paper, I develop the capacity view, that is, the view that perceptual experience has epistemic force in virtue of the epistemic and metaphysical primacy of the perceptual capacities employed in perception. By grounding the epistemic force of experience in facts about the metaphysical structure of experience, the capacity view is not only an externalist view, but moreover a naturalistic view of the epistemology of perceptual experience. So it is an externalist and naturalistic alternative to reliabilism. I discuss the repercussions of this view for the justification of beliefs and the epistemic transparency of mental states, as well as, familiar problem cases

Perception grounds demonstrative reference, yields singular thoughts, and fixes the reference of singular terms. Moreover, perception provides us with knowledge of particulars in our environment and justifies singular thoughts about particulars. How does perception play these cognitive and epistemic roles in our lives? I address this question by exploring the fundamental nature of perceptual experience. I argue that perceptual states are constituted by particulars and discuss epistemic, ontological, psychologistic, and semantic approaches to account for perceptual particularity.

I offer an explanation of how subjects are able to perceive the intrinsic spatial properties of objects, given that subjects always perceive from a particular location. The argument proceeds in two steps. First, I argue that a conception of space is necessary to perceive the intrinsic spatial properties of objects. This conception of space is spelled out by showing that perceiving intrinsic properties requires perceiving objects as the kind of things that are perceivable from other locations. Second, I show that having such a conception of space presupposes that a subject represent her location in relation to perceived objects. More precisely the thesis is that a subject represents her location as the location from which she both perceives objects and would act in relation to objects were she to act. So I argue that perception depends on the capacity to know what it would be to act in relation to objects