Photo: Micah Baldwin


Choosing a Warning Label for Human DNA

Many other planets circle other stars, as we now know. With practically infinite chances to evolve, other oceans must have oozed with life. A certain kind of optimist imagines that, if we ruin our own Earth, we can reseed our species there.

We might not know where we were going. The journey surely would be too long for living people to survive. But we know how to send seeds, perhaps frozen embryos, or merely strands of DNA. We could rely upon the kindness of strangers. An extraterrestrial host in space might reconstitute humanity.

Would they be glad they did? What kind of guests would we be on that world? Sending forth the seed of a species that has overrun and destroyed its own ecological niche—the Earth—we should at least include a warning label on the outside of the space capsule.

“Contents: Humanity. Use extreme caution. Highly invasive. Spreads rapidly. Wastes resources. Dangerous to all other species.”

This is not a safe addition to your garden. Not if you believe humans will someday so damage this home that only pioneering another planet can save us. If the people of that other world are wise, they will think carefully before renewing human existence from the seeds we send. They will surely consider how we handled our first planet before deciding if we should be trusted with theirs.

In the long saga of our evolution on Earth, those individuals who sought most vigorously to propagate their genes won the right to multiply and filled societies with strong competitors. The will to survive is powerful because those lacking it did not survive to reproduce. Our instinct for self-continuation is itself a primary reason for launching frozen embryos into space.

The cosmic irony of this scenario is that the same instinct that would motivate us to spread our seed in space would also make us unwelcome there. We may destroy the Earth satisfying a built-in competitive drive to copy our genes, but our other-world hosts won’t value human DNA so highly. They will see it as a collection of information for building animals that could compete with them on their world.

Why would they take the chance on defrosting our descendants? They might choose to destroy the embryos. Or they could hold human tissue the way labs on Earth hold cultures of eradicated diseases, like smallpox: for curiosity, but careful never to let them out into nature to reproduce freely.

A certain kind of optimist holds such a vision, as I said at the start. The kind of optimist who believes there will always be more resources for human beings to consume, allowing us to go on competing for comfort, prestige and dominance, to grow always more powerful, and always to produce more generations with more human beings who can repeat the geometric expansion of population and power.

That kind of optimist feels there is some intrinsic value to individuals so created—that the universe needs ever more selfish, materialistic strivers carrying our DNA. Our economic and political system is largely built on that premise. But it is a locally held sentiment. Unless we can travel to other worlds with the strength to force them to adopt the same extraordinary opinion of our value, it is unlikely to spread anywhere beyond the Earth.

Another kind of optimist would choose a different goal, and look to another strand of the human story for inspiration. On other worlds we may be useless, and our genetic code may be a random tale told out of context. But on this planet we have meaning and a place.

Human beings can and do make choices for the benefit of our planetary home and the other organisms who live here. We have in our genes social and altruistic impulses as well as competitive ones. In the total span of human existence, more people have lived in mutually supportive clans, villages and communities than in the hyper-individualistic culture now dominant.

These communitarian impulses drive us, too, and for most of us they are deeper and more fulfilling than naked materialism. The need to connect with others and with place. The yearning to be part of something larger, for spiritual meaning. The urge to dance and sing. Loving and being loved. The pleasure of giving.

The label on the capsule could say, “Contents: Humanity. Use extreme care. Highly sensitive. Needs and gives love. Forms strong connections. Adapts through upbringing to care for other species.”

But in the imagination of this kind of optimist, it’s unlikely a capsule would ever leave the Earth with a cargo of embryos. We would see that Earth is where we belong and would protect it. We wouldn’t want to subject our offspring to the cold uncertainty of space—we would want to raise them here, in the warmth of the sun, surrounded by the wonder of the Earth’s diversity and sensual embrace.

Here on Earth our genetic code makes sense. Here our bodies fit the ecosystem that sustains us—the air and sea, and the cousin animals that share so much of our DNA. Intuitions built into the folds of our brains grew here on the organic stuff of the savannah and forest, imprinted with the familiar acceleration of gravity and the 24-hour passage of the day.

We cannot stand alone. Along with embryos, a spaceship would have to send into space wombs for them to develop in, with the placenta that feeds us, and mother’s milk for the newborns, and the many species of micro-organisms that live within our bodies and keep us alive. We cannot digest food without an ecosystem of bacteria in the gut, different in each person, which comes to us from the environment of childhood.

This kind of optimist would imagine no need to leave the planet Earth. Instead, we would come to our senses in time to stop killing our life-support system, and not merely out of an instinct for survival. We would recognize that this place is bigger than us and better than our trivial and ephemeral material wants. We would remember where we came from and why we love to be alive.

On another planet, we’re irrelevant and superfluous. Here, our role is critical. We have the future of the Earth in our hands. If we count the Earth as worth anything, then the individual decisions we make daily are full of meaning.

Perhaps we would still choose to leave the planet now and then. Exploration can be noble, a search for knowledge and context. Going away can show us where we are, and why home matters. But we would remain creatures of our place. Only here are we whole, able to harmonize with a system of life of which we are a part.

We don’t have to spread like weeds. We can plant our seeds right here. If we tend our garden, we can stay indefinitely.

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