“lives in a pineapple under the sea... Absorbent and yellow and porous is he.”

NYTimes | It may be distressing to those committed to “autonomy,” but such manipulators have inherited the earth. Including us.

Take coughing, or sneezing. It may be beneficial for an infected person to cough up or sneeze out some of her tiny organismic invaders, although it isn’t so healthful for others nearby. But what if coughing and sneezing aren’t merely symptoms but also, even primarily, a manipulation of us, the “host,” by influenza viruses? Shades of zombie bees, fattened mice and grass-blade-besotted ants.

Just as Lenin urged us to ask “who, whom?” with regard to social interactions — who benefits at the expense of whom? — the new science of evolutionary medicine urges a similar question: who benefits when people show symptoms of a disease? Often, it’s the critters that are causing the disease in the first place.

But what about the daily, undiseased lives most of us experience? Voluntary actions are, we like to insist, ours and ours alone, not for the benefit of some parasitic or pathogenic occupying army. When we fall in love, we do so for ourselves, not at the behest of a romance-addled tapeworm. When we help a friend, we aren’t being manipulated by an altruistic bacterium. If we eat when hungry, sleep when tired, scratch an itch or write a poem, we aren’t knuckling under to the vices of our viruses.

But it isn’t that simple.

Think about having a child, and ask who — or rather, what — benefits from reproduction? It’s the genes. As modern biologists recognize, babies are our genes’ way of projecting themselves into the future.

Unlike the cases of parasites or pathogens, when genes manipulate “their” bodies, the situation seems less dire, if only because instead of foreign occupation it’s our genes, our selves. But those presumably personal genes aren’t any more hesitant about manipulating our bodies, and by extension our actions, than is a parasitic fly hijacking a honeybee.

Here, then, is heresy: maybe there is no one in charge — no independent, self-serving, order-issuing homunculus. Buddhists note that our skin doesn’t separate us from the environment, but joins us, just as biologists know that “we” are manipulated by, no less than manipulators of, the rest of life. Who is left after “you” are separated from your genes? Where does the rest of the world end, and each of us begin?

Let’s leave the last words to a modern icon of organic, oceanic wisdom: SpongeBob SquarePants. Mr. SquarePants, a cheerful, talkative — although admittedly, somewhat cartoonish — fellow of the phylum Porifera, “lives in a pineapple under the sea... Absorbent and yellow and porous is he.” I don’t know about the pineapple or the yellow, but absorbent and porous are we, too.