Now when you cut a forest, an ancient forest in particular, you are not just removing a lot of big trees and a few birds fluttering around in the canopy. You are drastically imperiling a vast array of species within a few square miles of you. The number of these species may go to tens of thousands. Many of them are still unknown to science, and science has not yet discovered the key role undoubtedly played in the maintenance of that ecosystem, as in the case of fungi, microorganisms, and many of the insects.

In science, obsessiveness under psychological control can be a virtue.

We exist in a bizarre combination of Stone Age emotions, medieval beliefs, and god-like technology.

Of course, there is no reconciliation between the theory of evolution by natural selection and the traditional religious view of the origin of the human mind.

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.

The ant world is a tumult, a noisy world of pheromones being passed back and forth.

Hands-on experience at the critical time, not systematic knowledge, is what counts in the making of a naturalist. Better to be an untutored savage for a while, not to know the names or anatomical detail. Better to spend stretches of time just searching and dreaming.