Who are we anyway?

According to an article posted on the N.Y. Times website today (George Johnson, "Cancer's Secrets Come Into Sharper Focus," August 15, 2011):

As they look beyond the genome, cancer researchers are also awakening to the fact that some 90 percent of the protein-encoding cells in our body are microbes. We evolved with them in a symbiotic relationship, which raises the question of just who is occupying whom.

“We are massively outnumbered,” said Jeremy K. Nicholson, chairman of biological chemistry and head of the department of surgery and cancer at Imperial College London. Altogether, he said, 99 percent of the functional genes in the body are microbial.

It seems to me that this report raises some question about just who "we" are. I admit I'm not at all expert on any of this, so what I'm saying here is frank speculation. In particular, I'm not sure what portion of human body cells are not protein-encoding, but one possibility is that all human body cells do this, so that what these researchers have found is that most of the cells inside our body are not human cells. If some human cells aren't protein-encoding, that would change the percentage of all cells inside us that are human -- but that would alter the point I'm making only in terms of percentages.

If, again, most cells inside us aren't human, and yet they are integral to us, and part of our daily operations, are they part of us? Suppose, as the article also suggests, that the human cells and the microbial ones may be in chemical communication, and this communication is integral (in some way we don't yet understand well at all) to our daily functioning. Should we say these nonhuman cells are no more "us" than inanimate oxygen or water molecules? But we are made up of inanimate molecules, rendered part of animate beings; the molecules are us. Are we equally made up of other animate beings? I've often thought that it is odd that we are made up of animate cells -- our own, human cells -- that somehow don't count as beings in their own right even though they live and die. But now we're talking about being made up of other beings, independent (though tiny and obscure) beings.

This feels rather weird, but it's not inconceivable. If tremendously powerful computing machines can be created by linking multiple separate machines together, it is conceivable that powerful beings can be created by somehow corralling multiple separate beings. We're accustomed to think of "us" as unities, but perhaps that's a mistake, and we're more like "products" of combining parts.

I'm not certain whether it matters what we're made up of -- whether we as composite creatures behave differently than we would if we were single unities, or whether we have different moral obligations. But the intuitive feeling I have (or "I" have) is that the fuzzier we are as beings, the more we should resist any simple prescriptions about what we must be or do. Even if that's not true, it's hard not to wonder who we are -- and I expect I'll be saying (speculating) more about this little matter in future posts.