Alder, Ken. The Measure of All Tings: The Seven-Year Odyssey and Hidden Error That


Alder, Ken. The Measure of All Tings: The Seven-Year Odyssey and Hidden Error That
Transformed the World. New York: The Free Press, 2002.

This is a wonderful account of the efforts by the French to standardize, to rationalize, their
system of measurement, the metric system. Recall that rationalization of measurements has a
long history (see Kula, Measures and Men) and any number of problems. So when the Academy
agreed to standardization (1792), it assigned two of its savants - Jean-Baptiste Joseph Delambre
(1749-1822) and Pierre-Francois-Andre Mechain (1744-1804) - to take an exact measurement of
a degree of latitude 1/10,000,000 of which would be the meter, the standard of length. It is most
important to recall that in this measurement, the meter was to be based on the real world, it was
not to be "constructed" by human, arbitrary standards. It was a metrologist's dream: a real
measure.. A capstone of this history is the attempt on the part of the French to establish a truly
rational measurement system, the metric system, which, as was said, would be "natural." The
French sought to devise a system of measures which used natural units of the real world: in the
case of the meter, 1/10,000,000 of the meridian which stretched between Dunkirk and Barcelona,
through Paris.

The short version of this story is that Mechain, charged with the measurement of the southern
portion of meridian, from Paris to Barcelona, made a mistake, knew he made a mistake, and - in
keeping with what he thought the role of the scientist - tried to cover his error. He wanted to look
good, he wanted to be a good scientist. So he tried fudging, he diddled, he did everything he
could to make his data come out right. But try as he might he could not hide his fakery and his
error came to light when examined by his colleague, Delambre. Delambre, the great historian of
science, was to look at his colleague's best efforts to maintain his reputation as a great scientist -
which Delambre could appreciate - and come to the conclusion that Mechain was not a poor or
bad scientist, but he did not understand "error." Indeed, understanding that error was "built into"
any system of measurement was the great advance achieved by Delambre's efforts to understand
the meaning of measurement. It was a dream of science to determine the meter exactly, and
humans had to learn to live with error. Fortunately for Delambre, there were mathematicians -
LePlace and Gauss - who both allowed for the development of a new theory of measurement, a
theory of error.

A comparison is in order and Alder compares Mechain's fudges to the work of Gregor Mendel
and Robert A. Millikan. Both have been accused of fudging their data on peas and the
measurement of drops of oil. Both used the "old" theory wherein the scientist used his data to
demonstrate his "results." As Alder puts it:

Modern science accepts error as its lot. It does not demand truth from its
practitioners, only honesty. It assumed that the truth will emerge eventually from
collective effort - so long as everyone is honesty. Certainly scientists care
passionately about getting the right answer. But when theory and experiment slign
too tightly, suspicion is warranted. Thus, the statistician R. A. Fisher concluded
that Gregor Johann Mendel's pea-breeding data could hardly have come as close
to the 1:3 genetic ratio as he claimed. The same holds for Robert Millikan, who
won a Nobel Prize for an electron experiment in which he suppressed anomalous
data. In Mendel and Millikan's day - from the nineteenth through the early
twentieth century - such fudges were common, though frowned on. Today they
continue, despite official censure. In Mechain's day, they were not only common,
they were considered a savant's prerogative. It was error that was seen as a moral
failing. (p. 301)

To put the matter succinctly, "As to whether perfection existed "out there," curled up in nature's
womb awaiting delivery, that was a theological question, and Delambre was a pagan....He was a
skeptical Stoic, for whom perfect knowledge lay beyond man's grasp. Why then should anyone
expect him to produce a perfect meter? ... Why measure the world to create a unit of length when
a standard "meter" could be created by legal fiat or simple agreement? It was absurd to travel so
far to find what lay so near... (p. 303)

To put it simply, "Delambre knew that the International Commission's boast of perfection was a
sham. The Commission had claimed to know the length of the meter to six significant difits, or
within 0.0001 perfect. Delambre now acknowledged that this was Ďa precision to which we ought
not to presume.' Now that the sanctified platinum bar was safely stored in the National
Archives - smug and untouchable in its triple-cocked box - he thought it only honest to admit as
much." (p. 303)

More philosophically, "Delambre had come to accept, as Mechain could not, the evanescence of
earthly knowledge. So to the extent that he conspired in his colleague's cover-up he did so for the
opposite reason: because he realized that getting the perfect answer did not matter. Which is to
say that Delambre understood that Mechain had agonized - and died - for nothing. We live on a
fallen planet, and there is no way bak to Eden. Delambre had decided to live on the surface of the
earth, buckled, bent, and warped though it was." (p. 304)

The insights of Gauss, Legendre and Leplace, would transform their insights concerning error
and thereby transform "savants" into "scientists."