Maybe it's better to start from obvious things. Color experience, for example. Can you tell which light of traffic lights is illuminated while you are not using position of light and you aren't asking himself which color it is? Is there something in your perception of different lights that allows you to tell that they are different?
The cones in the eye detect three different aspects of light (redness, greenness, blueness) and these are sent to the brain in three different fibers. By this mechanism we see there's nothing magic going on in telling the difference between two colors. I guess the rods (which detect variation in brightness) are more relevant to the question of which light is on though.
I encounter many intelligent people (not usually LWers, though) who say that despite our recent scientific advances, human consciousness remains a mystery and currently intractable to science. This is wrong. Empirically distinguishable theories of consciousness have been around for at least 15 years, and the data are beginning to favor some theories over others. For a recent example, see this August 2011 article from Lau & Rosenthal in Trends in Cognitive Sciences, one of my favorite journals. (Review articles, yay!)
Abstract: