Susanna Schellenberg

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? The 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.

Orthodoxy assumes that the first‐person thoughts of an individual are anchored to a stable object. I challenge this assumption by arguing that “I” is polysemous. The perspectival anchor of a first‐person thought could be the bearer of the thought, the agent, the bearer of perception, or a body, to name just a few options. These different possible anchors do not form a unity. So, a unified or minimal self cannot, without argument, be posited as the stable anchor of an individual's first‐person thoughts. I show how the polysemy of “I” can be analyzed in terms of polysemous mental files.

It is argued that perceptual experience provides us with both phenomenal and factive evidence. To a first approximation, one can understand phenomenal evidence as determined by how the environment sensorily seems to the subject when she is experiencing. To a first approximation, one can understand factive evidence as necessarily determined by the environment to which the subject is perceptually related such that the evidence is guaranteed to be an accurate guide to the environment. It is argued moreover that the rational source of both phenomenal and factive evidence lies in employing perceptual capacities that subjects have in virtue of being perceivers. By showing that both kinds of evidence have the same rational source, one can achieve a unified account of perceptual evidence and its rational source in perceptual experience.

I will exploit the basic commitments of capacitivism to develop a distinctive externalist view of perceptual knowledge. The basic idea of capacitivism is that perception is constitutively a matter of employing perceptual capacities that function to discriminate and single out particulars in our environment. It is because a given subject is employing perceptual capacities with a certain function that her mental states have epistemic force. Employing such perceptual capacities constitutes a mental state that provides us with phenomenal evidence, and employing such capacities in the good case also provides us with knowledge-worthy factive evidence. Capacitivism is an externalist view that does not invoke reliability, remains steadfastly naturalistic, and by recognizing a metaphysically substantive common element between perception and hallucination avoids any commitment to disjunctivism.

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.

In this chapter, Susanna Schellenberg develops a new understanding of singular modes of presentation. According to Fregean Particularism, singular modes of presentation are generated by the mental capacities employed that bring about the relevant mental state and the objects or features in the world (if any) thereby singled out. Consequently, modes of presentation can be individuated at the level of content types and token contents. Content types are individuated by the capacities employed. Content tokens are individuated by the capacities employed and the mind-independent particular thereby singled out. Applied to perception, the view holds that perceptions, hallucinations, and illusions with the same phenomenal character are constituted by employing the same perceptual capacities; they thereby share a content type. But the token content of perception, hallucination, and illusion differs at least in part.

Perception is to its core perspectival: we perceive our surrounding from a location, under specific lighting and acoustic conditions and other such perceptual conditions. Due to the perspectival nature of perception, any case of perception can have both variant and invariant properties. While the variant properties alter with changes in perceptual conditions, the invariant properties remain stable regardless of such changes. What is the nature of these variant and invariant properties? Are they properties in our environment? Are they properties of perceptual consciousness? By explaining the variant and invariant aspect of perceptual consciousness in terms of representations of external, mind-independent properties in our environment, this paper furthers an externalist account of perceptual consciousness. In doing so, it breaks with a long tradition—still alive today—of analyzing perspectival variance purely in terms of mind-dependent appearance properties. Perceptual variance is a key aspect of our subjective perspective and our egocentric point of view. The offered analysis of perspectival variance provides an explanation for how perspectival variance characterizes the subjective perspective of any perceiver—be it a dolphin, snake, or human.

This paper develops an account of perspectives that explains both perspectival stability and flexibility informed by research in neuroscience, cognitive psychology, and philosophy of mind. Any individual has limited processing resources, and so selects and represents only information pertinent to the situation or task at hand, filtering out information that can safely be ignored. An individual’s active perspective is anchored, for example, by her self-concept currently in force. This perspectival anchor can shift from moment to moment as she navigates her environment, thus yielding a change in her active perspective. However, the extent to which an individual’s active perspective can shift is restricted by her overall cognitive, perceptual, emotional, and agential schemas that constitute what we call her dormant perspective. Thus, while an individual’s dormant perspective changes only slowly over time, her active perspective can change abruptly.

Orthodoxy assumes that the first-person thoughts of an individual are anchored to a stable object. I challenge this assumption by arguing that “I” is polysemous. The perspectival anchor of a first-person thought could be the bearer of the thought, the agent, the bearer of perception, or a body, to name just a few options. These different possible anchors do not form a unity. So, a unified or minimal self cannot, without argument, be posited as the stable anchor of on individual’s first-person thoughts. I show how the polysemy of “I” can be analyzed in terms of polysemous mental files.

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.

This article defends liberalism, that is, the view that perceivers are justified in their perceptual beliefs simply on grounds of the perceptions on which the beliefs are based. By critically discussing several conservativist objections, it shows that liberalism is compatible with standard Bayesianism. This argument calls into question an assumption in the conservatist objections, an assumption that can be traced back to Pyrrhonian skepticism, namely, that the acquisition of perceptual evidence is primarily a matter of forming introspective beliefs about seemings or appearances. By contrast, this essay argues that the formation of introspective beliefs is an extra step over and above the acquisition of perceptual evidence. Forming the relevant introspective beliefs requires the possession of seeming or appearance concepts. However, subjects can acquire perceptual evidence, on this view, even if they lack these concepts or are incapable of forming the relevant introspective beliefs. Thus, the essay defends Bayesian liberalism.

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.

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.