A CRIMINAL HISTORY OF MANKIND

came to a complete halt in the middle of the sixth century B.C. It was not revived until more than
five hundred years later, when the militarist system in Sparta was finally smashed in the second
Macedonian war. A symbol of the sheer futility of the Spartan ideal can be seen in their later
custom of inducing boys to display their toughness by allowing themselves to be flogged to death at
the altar of the moon goddess.
The left cerebral hemisphere is the critical part of the brain, the part that can overrule our impulses.
(This explains why even cats and dogs have two hemispheres; all creatures need the power to
change their minds.) It would not be too inaccurate to say that the Spartans outlawed creativity and
turned themselves into a nation of critics. The left brain directs our energies into a narrow, fast
current like a mountain stream; the right allows them to spread into a broad, slow-moving river. But
the right also enables us to see where we are going, to survey the surrounding landscape and decide
where we want to go next. The left becomes easily trapped in its own obsessive forward movement
and loses all ability to change direction. When this happens, there are two possibilities: selfdestruction
or slow exhaustion. The Assyrians are an example of the first alternative, the Spartans
of the second.
Two thousand years or so later, Sherlock Holmes found himself confronting the same dilemma. In
his earlier days, Holmes was much given to relieving his boredom with morphine or cocaine.
When, in The Sign of Four, Watson asks him whether he has any work on hand at the moment,
Holmes replies: ‘None. Hence the cocaine. I cannot live without brain work. What else is there to
live for? Stand at the window here. Was ever such a dreary, dismal, unprofitable world? See how
the yellow fog swirls down the street and drifts across the dun-coloured houses. What could be
more hopelessly prosaic and material? What is the use of having powers, doctor, when one has no
field upon which to exert them?’ When Doyle wrote The Sign of Four, it was not recognised that
cocaine was addictive (Freud made his original reputation by administering it to cure morphine
addiction); and in any case Holmes was saved from addiction by his own increasing success. But
the example serves to show us that the nature of the problem has not changed in the three thousand
years since Rameses III. Man has achieved his pre-eminence by showing himself to be the greatest
of all survivors; he has survived droughts, ice-ages, famines and earthquakes. And at a certain point
in his history, evolution subjected him to the strangest of all experiments: confining his sense of
identity to his left brain. (It makes no difference whether or not we accept Jaynes’s estimate of
when this happened; the important thing is that it happened.) It paid off spectacularly. With this
new detachment from nature, man began to study it with a critical eye and observe its habits. In the
third century B.C., a Greek philosopher named Eratosthenes, who lived in Alexandria, heard that
there was a well in a town called Syene - modern Aswan - where the sun was reflected at midday
on midsummer day. This meant that it was precisely overhead, and that a tower in Syene would
cast no shadow. But towers in Alexandria did cast shadows at midday on midsummer day.
Eratosthenes measured such a shadow, and calculated that the sun’s rays struck the tower at an
angle of 7l/2°. And if the earth is a globe (a traditional piece of knowledge that seems to date back
to ancient Egypt), then the distance from Syene to Alexandria must be 7-1/2% of the earth’s
circumference. Since this distance is five hundred miles, Eratosthenes was able to work out that the
circumference of the earth must be 24,000 miles. The modern measurement is 24,860 miles at the
equator, so Eratosthenes was incredibly accurate. Another Alexandrian Greek, Aristarchus,
measured the angle from the earth to the sun when the moon was directly overhead and half-full,
then used simple trigonometry to work out the size of the sun and moon and their distances from
earth. His calculations were not quite as accurate as Eratosthenes’, because of the difficulty of
judging exactly when the moon was half-full; but he worked out that the moon is fifty-six thousand