In this chapter I will be concerned with a group of interrelated episte-mological problems.

The first of these problems is the traditional problem of other minds. Let us say that a qualitative characteristic of sensations is an immediate quale if one or more human beings have direct access to it. Now common sense encourages one to hold that other human beings have sensations that are more or less similar to one's own, in the sense of exemplifying immediate qualia that are more or less like the immediate qualia one's own sensations exemplify. Common sense also encourages one to hold that the same is true, though to a lesser degree, of the members of certain biological species that are not too distant from homo sapiens. Can these beliefs be justified? If so, how? These two questions constitute the traditional problem of other minds.

Assuming that this first problem admits of a positive solution, in the sense that it is possible to show that our intuitions about other human beings and members of neighboring biological species are justified, the question arises whether it is possible to justify ascriptions of sensations with immediate qualia (hereafter called immediate sensations) to beings who stand at some remove from ourselves.