It is in our collective behavior that we are most mysterious.

Perhaps the safest thing to do at the outset, if technology permits, is to send music. This language may be the best we have for explaining what we are like to others in space, with least ambiguity. I would vote for Bach, all of Bach, streamed out into space, over and over again. We would be bragging of course, but it is surely excusable to put the best possible face on at the beginning of such an acquaintance. We can tell the harder truths later.

We owe our lives to the sun... How is it, then, that we feel no gratitude?

Although I usually think I know what I'm going to be writing about, what I'm going to say, most of the time it doesn't happen that way at all. At some point I get misled down a garden path, I get surprised by an idea that I hadn't anticipated getting, which is a little bit like being in a laboratory.

We're as clever as we think we are, but we'll be a lot cleverer when we learn to use not just one brain but to pool huge numbers of brains. We're at a level technologically where we can share information and think collectively about our problems. We do it in science all the time - there's no reason why we can't do it in other endeavors.

Well, biology today as I see it has an amiable look - quite different from the 19th-century view that the whole arrangement of nature is hostile, 'red in tooth and claw.' That came about because people misread Darwin's 'survival of the fittest.'

We have come a long way on that old molecule DNA.