Online research in philosophy

Marr (1982) may have been one of the first vision researchers to insist that in modeling vision it is important to separate the location of visual features from their type. He argued that in early stages of visual processing there must be “place tokens” that enable subsequent stages of the visual system to treat locations independent of what specific feature type was at that location. Thus, in certain respects a collinear array of diverse features could still be perceived as a line, and under certain conditions could function as such in perceptual phenomena like the Poggendorf illusion.

Perception is often analysed as a process in which causal events from the environment act on a subject to produce states in the mind or brain. The role of the subject is an increasing feature of neuroscientific and cognitive literature. This feature is linked to the need for an account of the normative aspects of perceptual competence. A holographic model is offered in which objects are presented to the subject classified according to rules governing concepts and encoded in brain function in that form. This implies that the analysis of perception must consider not only the fact that there is an interaction between the perceiving subject and the perceived object but also that the interaction is shaped by a system of concepts which the subject uses in thought and action.

This article discusses the theories of perception of Robert Kilwardby and Peter of John Olivi. Our aim is to show how in challenging certain assumptions of medieval Aristotelian theories of perception they drew on Augustine and argued for the active nature of the soul in sense perception. For both Kilwardby and Olivi, the soul is not passive with respect to perceived objects; rather, it causes its own cognitive acts with respect to external objects and thus allows the subject to perceive them. We also show that Kilwardby and Olivi differ substantially regarding where the activity of the soul is directed to and the role of the sensible species in the process, and we demonstrate that there are similarities between their ideas of intentionality and the attention of the soul towards the corporeal world.

To what extent is the external world the way that it appears to us in perceptual experience? This perennial question in philosophy is no doubt ambiguous in many ways. For example, it might be taken as equivalent to the question of whether or not the external world is the way that it appears to be? This is a question about the epistemology of perception: Are our perceptual experiences by and large veridical representations of the external world? Alternatively, the question might be taken as asking whether or not the external world is like its ways of appearing to us, where the expression “ways of appearing” is intended to pick out aspects of our perceptual experiences themselves. This is a metaphysical version of the question of the relationship between appearance and reality: What is the relationship between the phenomenal features that characterize perceptual experience, on the one hand, and the mind-independent features of the external objects of perception, on the other? There are some philosophers who might resist distinguishing between these two questions. For them, “ways of appearing” in the phenomenal sense just are the ways that things appear to be (let’s call the latter the “intentional sense” of “ways of appearing”).1 That is, the phenomenal character of an experience is nothing over and above its representational content. Phenomenal properties are represented properties—the properties that an experience attributes to the external objects of perception. The question of whether or not phenomenal properties can be identified with the represented properties of an experience mirrors traditional questions in the philosophy of perception. If they can be identified with each other, then in veridical perception we might be said to “directly grasp” features of the external world through perception. The properties that are present to the mind are the very same properties that belong to the external objects of perception. Such a view affords....

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.

Ross argues that the location problem for color-the problem of how it is represented as occupying a particular location in space-constitutes an objection to color subjectivism. There are two ways in which the location problem can be interpreted. First, it can be read as a why-question about the relation of visual experience to the environment represented: Why does visual experience represent a patch of color as located in this part of space rather than that? On this interpretation, the subjectivist can answer Ross's objection by appealing to the physical location of reflectance rather than color. Second, it can be read as a how-question about visual representation itself: How does visual experience put together the experience of a color with the experience of its being located in space? This version makes the location problem a problem about visual experience itself and renders the ontology of color irrelevant to its solution. The location problem is thus no more a problem for the color subjectivist than for the color realist.

Color subjectivists claim that, despite appearances to the contrary, the world external to the mind is colorless. However, in giving an account of color perception, subjectivists about the nature of perceived color must address the nature of perceived spatial location as well. The argument here will be that subjectivists’ problems with coordinating the metaphysics of perceived color and perceived location render color perception implausibly mysterious. Consequently, some version of color realism, the view that colors are (physical, dispositional, functional, sui generis, or some other) properties of physical objects, is correct.

The fundamental philosophical interest in perception is to answer the question of how perception can give us knowledge of the world. One of the challenges in answering this question is that perception is necessarily tied to a particular time and place. One necessarily perceives from a particular location and at a particular time. As a consequence, what is immediately perceptually available is subject to situational features, such as one’s point of view and the lighting conditions. But although objects are always perceived subject to situational features, one can perceive the shape and color of objects.¹ One can perceive the shape of objects although only the facing surfaces are visible and one can perceive two objects to be the same size although one is nearer than the other. Similarly, one can perceive the uniform color of a surface although parts of it are illuminated more brightly than others² and one can recognize the sound of a cello regardless of whether it is played on a street or in a concert hall. More generally, one can perceive the properties objects have regardless of the situational features, although one always perceives them subject to situational features.

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 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.