John H. Campbell

This chapter makes the case for a relational version of an experientialist view of joint attention. On an experientialist view of joint attention, shifting from solitary attention to joint attention involves a shift in the nature of your perceptual experience of the object attended to. A relational analysis of such a view explains the latter shift in terms of the idea that, in joint attention, it is a constituent of your experience that the other person is, with you, jointly attending to the object. We need such an analysis of joint attention to explain the possibility of success in tasks such as coordinated attack.

It seems a compelling idea that experience of colour plays some role in our having concepts of the various colours, but in trying to explain the role experience plays the first thing we have to describe is what sort of colour experience matters here. I will argue that the kind of experience that matters is conscious attention to the colours of objects as an aspect of them on which direct intervention is selectively possible. As I will explain this idea, it is a matter of being able to use experience to inform linguistic or conceptual thought about what would happen were there to be various interventions on an object. Against this background, I will review Locke’s fundamental argument that since we can change the colour of an almond by pounding it, there must be an error embodied in our ordinary concepts of colour: there is no such thing as intervening directly on the colour of an object. The analysis I present brings out the force of Locke’s argument. But I will propose a vindication of our commonsense conception of colour as an aspect of objects on which direct intervention is selectively possible

I set out two theses. The first is Lynn Robertson’s: (a) spatial awareness is a cause of object perception. A natural counterpoint is: (b) spatial awareness is a cause of your ability to make accurate verbal reports about a perceived object. Zenon Pylyshyn has criticized both. I argue that nonetheless, the burden of the evidence supports both (a) and (b). Finally, I argue conscious visual perception of an object has a different causal role to both: (i) non-conscious perception of the object, and (ii) experience, e.g. hallucination, that may be subjectively indiscriminable from, but is not, perception of the object.

What knowledge of the colors does perception of the colors provide? My first aim in this essay is to characterize the way in which color experience seems to provide knowledge of colors. This in turn tells us something about what it takes for there to be colors. Color experience provides knowledge of the aspect of the world that is being acted on when we, or some external force, act on the color of an object and thus make a difference to the experiences of people looking at it. It is in this sense that the nature of the colors is transparent to us. For there to be colors is for there to be the qualitative categorical properties that we encounter in perception, action on which affects the color experiences of observers. This line of thought contrasts with the idea that color experience reveals the colors to us, in the sense that it provides knowledge of a number of necessary truths about the colors. In a recent paper, Alex Byrne and David Hilbert provide a careful exposition and critique of this way of developing the idea of color experience as revelatory of the colors. In this paper my main aim is simply to contrast the idea that experience makes the colors transparent to us, with the idea that color experience provides us with knowledge of truths relating to the essences of the colors

1. The spatial perception requirementCassam surveys arguments for what he calls the ‘Spatial Perception Requirement’ . This is the following principle: " SPR: In order to perceive that something is the case and thereby to know that it is the case one must be capable of spatial perception. " A couple of preliminary glosses. By ‘spatial perception’ Cassam means either perception of location, or perception of specifically spatial properties of an object, such as its size and shape. Second, Cassam takes it that there is something basic about cases in which one's perceiving that something is the case depends on perception of an object. That is, he takes it that there is something basic about such cases as that in which, for example, you perceive that the door is open by perceiving the door.On this second point, it is not quite obvious that one could not perceive that things are thus and so if one could not perceive material objects. Cannot someone lost in fog, for example, perceive that it is foggy, even if they cannot see a thing because of the fog? Moreover, suppose we have someone who cannot perceive that things are thus and so. This person has only a series of sensations. Is it obvious that this person could not come to have knowledge of their world by reasoning about the probable causes of those sensations? These points seem to me to have some interest, but I will not pursue them here. I will assume we are considering cases in which propositional knowledge is grounded in perception that such and such is the case, and that this in turn depends on perception of objects.One sort of argument you might give for SPR runs as follows. Perception of an object demands that you have perceptually differentiated the object from its …

Suppose your conscious life were surgically excised, but everything else left intact, what would you miss? In this situation you would not have the slightest idea what was going on. You would have no idea what there is in the world around you; what the grounds are of the potentialities and threats are that you are negotiating. Experience of your surroundings provides you with knowledge of what is there: with your initial base of knowledge of what the things are that you are thinking and talking about. But this connection between consciousness of the objects and properties around you, and knowledge of the references of the basic terms you use, has proven difficult to articulate. The connection cannot be recognized so long as you think of consciousness as a kind of glow with which representations are accompanied or enlivened. It is, though, also possible to think of perceptual experience as fundamentally a relation between the subject and the things experienced; and given such a conception, we can make visible the link between consciousness and reference.

Ordinary common sense suggests that we have just one set of shape concepts that we apply indifferently on the bases of sight and touch. Yet we understand the shape concepts, we know what shape properties are, only because we have experience of shapes. And phenomenal experience of shape in vision and phenomenal experience of shape in touch seem to be quite different. So how can the shape concepts we grasp and use on the basis of vision be the same as the shape concepts we grasp and use on the basis of touch? I think this is the intuitive puzzle that underlies the question sent by the Dublin lawyer Molyneux to John Locke. This concerns a man born blind, who learns by the use of his touch to discriminate cubes from spheres. Suppose him now to gain the use of his sight. And suppose him to be presented with a cube and a sphere, of nighly the same bigness. Quaere, will he be able to tell, by the use of his vision alone, which is the sphere, and which the cube? (Locke 1975, II/ix/8.)

It is sometimes said that ordinary linguistic exchange, in ordinary conversation, is a matter of securing and sustaining joint attention. The minimal condition for the success of the conversation is that the participants should be attending to the same things. So the psychologist Michael Tomasello writes, ‘I take it as axiomatic that when humans use language to communicate referentially they are attempting to manipulate the attention of another person or persons.’ I think that this is an extremely fertile approach to philosophical problems about meaning and reference, and in this paper I want to apply it to the case of the first person. So I want to look at the case in which you tell me something about yourself, using the first person, and we achieve joint attention to the same object. But I begin with some remarks about how this approach applies to proper names and to perceptual demonstratives