Here is an old question in the philosophy of perception: here I am, looking at the pen on my desk. Presumably I really am seeing this pen. Even so, I could be having an experience just like the one I am having without anything being there. So how can the experience I am having really involve direct awareness of the pen? It seems as though the presence of the pen is inessential to the way the experience is.

Traditionally, this question was used to raise skeptical worries about perceptual experience and to motivate the sense-data thesis, according to which perceptual experiences, even veridical ones, are directly of mental or private objects and only indirectly of their physical objects. I addressed these epistemological and ontological problems in my dissertation several decades ago, but it is not yet time for me to take them up again. What interests me here is what might be called the semantic problem of perceptual experience. It concerns the fact that experiences are directed at objects. This is what John Searle and many other philosophers call the Intentionality of experience.

Here I am looking at this pen. What makes it the case that it is this pen that I am experiencing, that it is the one that appears to me of such-and-such shape, size, and color? The problem here is that there is nothing in the character of my visual experience to distinguish this pen from any other pen that would look just like it.