Professor David Barash published an article in the NY Times recently discussing how parasites make use of and even manipulate their host’s behavior, often in remarkable and creepy ways. He asks whether we humans are likewise fulfilling the needs of the tiny creatures within us (and the needs of our genes, which aren’t tiny creatures but lists of instructions).

Professor Barash concludes with what he says is a heretical possibility: “Maybe there is no one in charge — no independent, self-serving, order-issuing homunculus”. But this isn’t such a heretical idea, at least not a new one. Philosophers, most famously David Hume, have long questioned whether there is a self, a single self-conscious mental entity that is “me”. Hume claimed that all he was conscious of was “a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement” (A Treatise of Human Nature, Book I, Part IV, Section VI).

What everyone should agree on is that we are biological organisms, living things composed of trillions of much smaller living things. The human body is composed of roughly 10 trillion living cells. In addition, we provide living space to roughly 100 trillion other life forms, mostly bacteria, mostly in our intestines. Each one of us is a community. Somehow the operation of this community results in the almost overwhelming conviction that we have a single seat of consciousness, observing the world and controlling our actions.

How this happens is still a mystery. But it might change our perspective on who we are if we keep in mind that every action we perform, every thought we have, reflects the actions of a small universe of other living things.

http://www.nytimes.com/2012/10/07/opinion/sunday/whos-in-charge-inside-your-head.html?ref=opinion