Scientist: Four golden lessons

Scientist: Four golden lessons

STEVEN WEINBERG

Steven Weinberg is in the Department of Physics, the University ofTexas at Austin, Texas 78712, USA. This essay is based on acommencement talk given by the author at the Science Convocation atMcGill University in June 2003.

When I received my undergraduate degree about a hundred years ago thephysics literature seemed to me a vast, unexplored ocean, every part ofwhich I had to chart before beginning any research of my own. How couldI do anything without knowing everything that had already been done?Fortunately, in my first year of graduate school, I had the good luckto fall into the hands of senior physicists who insisted, over myanxious objections, that I must start doing research, and pick up whatI needed to know as I went along. It was sink or swim. To my surprise,I found that this works. I managed to get a quick PhD — though when Igot it I knew almost nothing about physics. But I did learn one bigthing: that no one knows everything, and you don't have to.

Another lesson to be learned, to continue using my oceanographicmetaphor, is that while you are swimming and not sinking you should aimfor rough water. When I was teaching at the Massachusetts Institute ofTechnology in the late 1960s, a student told me that he wanted to gointo general relativity rather than the area I was working on,elementary particle physics, because the principles of the former werewell known, while the latter seemed like a mess to him. It struck methat he had just given a perfectly good reason for doing the opposite.Particle physics was an area where creative work could still be done.It really was a mess in the 1960s, but since that time the work of manytheoretical and experimental physicists has been able to sort it out,and put everything (well, almost everything) together in a beautifultheory known as the standard model. My advice is to go for the messes:that's where the action is.

My third piece of advice is probably the hardest to take. It is toforgive yourself for wasting time. Students are only asked to solve problems that their professors (unless unusually cruel) know to besolvable. In addition, it doesn't matter if the problems arescientifically important: they have to be solved to pass the course.But in the real world, it's very hard to know which problems areimportant, and you never know whether at a given moment in history aproblem is solvable. At the beginning of the twentieth century, severalleading physicists, including Lorentz and Abraham, were trying to workout a theory of the electron. This was partly in order to understandwhy all attempts to detect effects of Earth's motion through the etherhad failed. We now know that they were working on the wrong problem. Atthat time, no one could have developed a successful theory of theelectron, because quantum mechanics had not yet been discovered. Ittook the genius of Albert Einstein in 1905 to realize that the rightproblem on which to work was the effect of motion on measurements ofspace and time. This led him to the special theory of relativity. Asyou will never be sure which are the right problems to work on, most ofthe time that you spend in the laboratory or at your desk will bewasted. If you want to be creative, then you will have to get used tospending most of your time not being creative, to being becalmed on theocean of scientific knowledge.
Finally, learn something about the history of science, or at a minimumthe history of your own branch of science. The least important reasonfor this is that the history may actually be of some use to you in yourown scientific work. For instance, now and then scientists are hamperedby believing one of the over-simplified models of science that havebeen proposed by philosophers from Francis Bacon to Thomas Kuhn andKarl Popper. The best antidote to the philosophy of science is aknowledge of the history of science.

More importantly, the history of science can make your work seem moreworthwhile to you. As a scientist, you're probably not going to getrich. Your friends and relatives probably won't understand what you'redoing. And if you work in a field like elementary particle physics, youwon't even have the satisfaction of doing something that is immediatelyuseful. But you can get great satisfaction by recognizing that your work in science is a part of history.

Look back 100 years, to 1903. How important is it now who was PrimeMinister of Great Britain in 1903, or President of the United States?What stands out as really important is that at McGill University,Ernest Rutherford and Frederick Soddy were working out the nature ofradioactivity. This work (of course!) had practical applications, butmuch more important were its cultural implications. The understandingof radioactivity allowed physicists to explain how the Sun and Earth'scores could still be hot after millions of years. In this way, itremoved the last scientific objection to what many geologists andpaleontologists thought was the great age of the Earth and the Sun.After this, Christians and Jews either had to give up belief in theliteral truth of the Bible or resign themselves to intellectualirrelevance. This was just one step in a sequence of steps from Galileothrough Newton and Darwin to the present that, time after time, hasweakened the hold of religious dogmatism. Reading any newspapernowadays is enough to show you that this work is not yet complete. Butit is civilizing work, of which scientists are able to feel proud.