In 2010, my two Harvard mathematician colleagues and I dismantled kin-selection theory, which was the reigning theory of the origin of altruism at the time.

Biophilia, if it exists, and I believe it exists, is the innately emotional affiliation of human beings to other living organisms.

Nature first, then theory. Or, better, Nature and theory closely intertwined while you throw all your intellectual capital at the subject. Love the organisms for themselves first, then strain for general explanations, and, with good fortune, discoveries will follow. If they don't, the love and the pleasure will have been enough.

An Armageddon is approaching at the beginning of the third millennium. But it is not the cosmic war and fiery collapse of mankind foretold in sacred scripture. It is the wreckage of the planet by an exuberantly plentiful and ingenious humanity.

If we lose half the species, which could happen by the end of the century if we don't do anything, that's going to create a big difference down the line in the stability and even the economic potential in the living world. Irreversibly.

Humanity is a biological species, living in a biological environment, because like all species, we are exquisitely adapted in everything: from our behavior, to our genetics, to our physiology, to that particular environment in which we live. The earth is our home. Unless we preserve the rest of life, as a sacred duty, we will be endangering ourselves by destroying the home in which we evolved, and on which we completely depend.

We don't know nearly enough about the complexities of Nature. If we think we can eliminate natural ecosystems and substitute prosthetic devices, i.e. clean air or water with fusion energy - we are kidding ourselves.