It's obvious that the key problem facing humanity in the coming century is how to bring a better quality of life - for 8 billion or more people - without wrecking the environment entirely in the attempt.

Overall, the human brain is the most complex object known in the universe - known, that is, to itself.

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.

When you have seen one ant, one bird, one tree, you have not seen them all.

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.

I like what Abba Eban once said during the 1967 war. He said, "When all else fails, men turn to reason."

The real problem of humanity is the following: we have paleolithic emotions; medieval institutions; and god-like technology. And it is terrifically dangerous, and it is now approaching a point of crisis overall.