JB: Talk about the end of science versus the limits of science.

TRAUB: I assume that you're referring to John Horgan's book, "The Ends of Science". John sent me the manuscript last fall for my comments. I suggested some minor technical corrections and told him I totally disagreed with his thesis that science had made such extraordinary progress that its golden age was over and only mopping up was left. Incidentally, the manuscript was titled "The Ends of Science", which is an ambiguous and far more interesting title. Apparently the publisher changed that to "The End of Science", hoping to derive some advantage from the success of books titled The End of You Name It, starting with Francis Fukuyama's foolish "The End of History".

John writes very well indeed; he is a senior writer for "Scientific American", and his book features juicy anecdotes about many scientists who are household names. However, I never would have predicted the amount of media attention that the book has actually received. Its message is basically pessimistic. For example, a column in the New York Times stated that Horgan found in his interviews with some of today's leading scientists an atmosphere of anxiety and melancholy and little acknowledgment that the great era of scientific discovery is over.

Those are not the emotions of the scientists that I know. The ones with whom I'm in touch are vitally excited by their work. There's more to be done than ever, and we can't wait to get on with it.

I'm not saying that there aren't difficulties. Funding for research has leveled off and will probably decrease. Universities don't have tenure positions available for young scientists. The emphasis in some of the leading corporate laboratories has shifted away from basic research. The Federal laboratories are in turmoil due to budget cuts and re-direction. But such difficulties are to be expected after the period of unparalleled growth which followed the Second World War. Horgan is claiming it's all over because the fundamental discoveries have been made.

Earlier I mentioned a very partial list of big scientific questions. Let me repeat a couple of items from that list: How do physical processes in the brain give rise to subjective experience? That is, explain consciousness. Is there life elsewhere in the universe? Is it intelligent? Will the universe expand forever or will it collapse?

I don't find John Horgan's thesis, that all the important discoveries are behind us, very compelling. Furthermore, each major advance leads to important new questions. Reports of the death of science have been greatly exaggerated. Indeed, I believe they're just plain wrong.

JB: What are the great unknowables that you see worthy of study?

TRAUB: Remember that we have to distinguish between the unknown and the unknowable. There's a very big list of things we don't know. Which important questions might be unknowable? I'll mention just four of them here. Although what I'd said earlier about mathematical models is solidly grounded, what I'll now say is highly speculative. I hope the readers of this interview will be forgiving.

The first has to do with earth systems predictability. There are many interesting questions here. Some people believe earthquakes, like Per Bak's sandpile, are a self-organizing phenomenon and are intrinsically unpredictable. On the other hand, my colleague Lynn Sykes at Lamont Doherty Earth Observatory believes that though we probably cannot predict two to three earthquakes out, we can predict the next big one in a geographic area. Of course, warning a population that a big one is coming has major social consequences. Another example of a question with enormous implications for humans is whether there will be major global changes due to human activities. What will be the effects on earth's ocean levels, and on agriculture and biodiversity?

A second is the likelihood of other intelligent life in the universe. Stephen Jay Gould argues that it's extremely improbable because so many unlikely accidents have to happen. He believes if the tape were to be replayed, we would not have evolved. My Santa Fe Institute colleague Stuart Kauffman argues that order comes for free and that we are "at home in the universe". Other than by discovering intelligent life forms elsewhere, can this question be resolved?

A third is whether we can understand consciousness. Some believe this to be unknowable while others believe the answer can be found within science. I have a 16-month old grandson and as I was watching him while he was still pre-verbal I wondered about his cognitive learning processes. He sure was busy crawling, looking and manipulating but what was going on inside? And what did he learn in the fetal stage?

My final question is whether we can keep the U.S. economy, let alone the international economies with which we are so interdependent, on an even keel. Basically, things have been pretty good since the Great Depression. Right now, it looks good. But we have coupled nonlinear systems and we know that such systems often exhibit chaos. Can the system be kept going for a "long" period of time without dreadful economic disasters? How might this be achieved?

There are so many wonderful questions. I guess I've been very lucky. I got interested in computers over forty years ago and I keep expecting to run out of interesting questions. But I never have to strip-mine. I just walk along and pick up diamonds.