Evolution by natural selection is not an idle hypothesis. The genetic variation on which selection acts is well understood in principle all the way down to the molecular level.

The worst thing that will probably happen-in fact is already well underway-is not energy depletion, economic collapse, conventional war, or the expansion of totalitarian governments. As terrible as these catastrophes would be for us, they can be repaired in a few generations. The one process now going on that will take millions of years to correct is loss of genetic and species diversity by the destruction of natural habitats. This is the folly our descendants are least likely to forgive us.

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.

Yes, the natural sciences are telling us a great deal about human origins, the origins of our species the origins of our minds; we're on our way to explaining a large part of it. I'll accept an answer provided only by such means as obtaining and exploring, analyzing and arguing over the evidence - not because of a scribe's myopic view of the subject written 500 years before the birth of Christ!

We don't even know what species are out there, for the most part, particularly when you get down to the microbes and very small invertebrates. They make up the mass of the organisms around us, including the soil we depend on, the soil of cornfields as well as hardwood forests. We haven't taken ecology to the point where we can even make a crude prediction of what's going to happen when we've reduced the living world down to a certain level.

The two major challenges for the 21st century are to improve the economic situation of the majority and save as much of the planet as we can.

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