What Are the Units, and Why? Review of The Science of Measurement: Taking the Measure of the World

W you hop the Atlantic with a BBC program, the odds are good that someone will want to rename it for an American audience. Which is too bad, in this case, because the British title for Marcus du Sautoy’s three-parter on measurement is closer to the mark: Precision: The Measure of All Things. I've been thinking about precision lately, because 32 years after a college boyfriend tried to get me to read Feynman’s physics lectures, I’m finally capable of reading them. And not only are they wonderful lectures, but along the way Feynman says all kinds of things that would have helped me immensely in high school. Have a look at this, for instance, from his chapter on motion: The theory of relativity shows that our ideas of space and time are not as simple as one might think at f irst sight. However, for our present purposes, for the accuracy that we need at f irst, we need not be very careful about def ining things precisely. Perhaps you say, ‘That’s a terrible thingI learned that in science we have to def ine everything precisely.’ We cannot def ine anything precisely! If we attempt to, we get into that paralysis of thought that comes to philosophers, who sit opposite each other, one saying to the other, “You don’t know what you are talking about!” The second one says, “What do you mean by know? What do you mean by talking? What do you mean by you?” and so on. In order to be able to talk constructively, we just have to agree that we are talking about roughly the same thing.