and thanks for the rep, but I like my horsey.... and he's not that high, he only smokes in the evening.
I think Kant went further and said our entire experience with reality is a function of our perceptions--including those you say are "primary". We can infer their entitivity, but we can't really deal with them directly.
I think consciousness is awareness--the part of self I most identify as me, and the part of reality that is most directly accessible to me. In that respect, I think Descartes was right. From an evolutionary standpoint, consciousness is something of a mystery. As others have pointed out, we don't know the function of consciousness. Why couldn't zombies lacking consciousness do the same job? One poster suggested that consciousness might be a spandrel--a byproduct or epiphenomenon resulting from the evolution of other human features. What a remarkably fortuitous accident! Without consciousness, no one would appreciate what a great big wonderful multiverse we live in. Of course, some of us Christian types get mystical about it and posit the metaphysical explanation that the emergence of consciousness is what it's all about.
to me, the mind isn't the end user. it is the operating system and interface, between the self and the brain. that there is a separate non-physical true self, distinct from mind, which is analogous to software, running on the wetware/computer that is the physical brain. of course one can argue for the non-physicality of software too, that it is an emergent phenomena. but it is based on data, which are physical state instances.