A few weeks ago, a student in my MA course posted a question that took a little while to answer. I'm including it, and my answer here for reference.
Can someone please explain to me how qualia links into what constitutes the self? I seriously cannot see the correlation.
Most philosophers seem able to agree on at least this much: that if there are such things as qualia, then what they do is carry the elemental bits of any subjective experience “to” the subject having the experience. What someone describes when talking about a single quale is very small; it might be most analogous to the color of a single pixel represented on a theater screen.
That the analogy is of the pixel’s color, and not the pixel itself is important: qualia do not represent experiences; they are constitutive of them. Subjective life without any qualia at all is to some people a meaningless statement. It would be like saying there could be such a thing as an experience “over there” being “had” by nothing; or more specifically, having an experience without qualia is akin to not having an experience at all. If this is a little confusing, perhaps a clearer way of putting it is describing three people watching a film. The first watcher is deaf, and so her experience includes no aural qualia; the second is blind, and experiences no visual qualia. The third is deaf, and blind, and so may very well be described as not experiencing the film at all- so once again, the elimination of qualia constitutes the elimination of experience.
Now you’re probably still wondering, “what does this have to do with the self?” First, there’s quite a bit of literature on the concept of “philosophical zombies”, which are easily defined as people who lack any qualia at all. As this notion runs, these people walk, talk, and act just like you or I do, but all their responses and activities lack any sort of subjective perspective or personal experience - they are neither self-conscious, or can even be said to be strictly aware of anything, any more than a thermostat is “aware” of temperature fluctuations (which is where the debates usually begin). As these creatures ostensibly have no qualia, there is no sense in which it is coherent to say that there is some way it’s “like” to be a p-zombie, and without this sense of being it becomes very difficult to say whether it’s possible to claim that these creatures have anything like a personal identity- there is no subjectivity there, for any properties we normally ascribe to ourselves to "hang on to", so to speak.
So this is how qualia come to be constitutive of selves. That they exist implies that an experience, however minimal, is being had, by some subject; that subject of the experiences we have is what we normally come to call “ourselves”.