Of Spiders and Bees 183most impressive of the grand systems of natural law— including rules on
relations between states, but by no means limited to that.
Among the Grotians, some were in the far reaches of the rationalist end of
the international- law spectrum, even if they were not quite at the extreme
point of the naturalist school. Foremost among these was another German
writer, Christian Wolff , in the early and mid- eighteenth century. Although
little remembered in most circles today, he was the towering intellectual fi g-
ure in the Germany of his era. He was from Breslau in Silesia (present- day
Wroclaw in Poland) and studied (like Pufendorf) at the University of Leipzig.
Appropriately for a leading fi gure of the rationalist persuasion, his original
fi eld of study was mathematics, with his dissertation at Leipzig on the sub-
ject of the application of mathematical methods to ethics. He went on to a
professorship in mathematics at the University of Halle. Trouble came, how-
ever, as a result of his rectoral address in 1721, “On the Practical Philosophy
of the Chinese.” Th at might seem an innocuous enough topic. But Wolff ’s
assertion that sound moral reasoning did not require belief in God or reli-
ance on revelation earned him the hostility of conservative theologians. He
was no radical, being a defender of slavery and of torture in judicial pro-
ceedings. But in 1723, he was dismissed from his post and given forty- eight
hours to leave Prus sia. He taught at the University of Marburg until allowed,
by Prus sian King Frederick II, to return to Halle in 1740— to a hero’s wel-
come. He went on to become vice- chancellor of Halle and a baron of the Holy
Roman Empire, as well as the foremost intellectual of the German world.
Wol ff was the very prince of pedants. As a mathematician, he brought the
study of the calculus into German university teaching. He became an im-
portant fi gure, too, in the history of psychology— and was even responsible
for bringing that word into general usage. He brought the hypothetico-
deductive mode of thought to bear on the subject of astronomy, too, with
intriguing results. Arguing from a fundamental principle of nihil frustra
(“nothing happens to no purpose”), he concluded that the moon, other
planets, and even comets were populated by plants, animals, and humans.
He even went so far as to calculate the bodily size of the inhabitants of Jupi-
ter. Th ey must have larger eyes than their terrestrial counterparts, he wisely
surmised, given that the sunlight reaching them would be less intense. Let
it never be said that the patient application of reason does not broaden one’s
horizons.