A History of Science, vol 2 | Page 4

the successors of Galileo, who were also the
predecessors and contemporaries of Newton.

In general, it will aid the reader to recall that, so far as possible, we
hold always to the same sequences of topical treatment of
contemporary events; as a rule we treat first the cosmical, then the
physical, then the biological sciences. The same order of treatment will
be held to in succeeding volumes.
Several of the very greatest of scientific generalizations are developed
in the period covered by the present book: for example, the Copernican
theory of the solar system, the true doctrine of planetary motions, the
laws of motion, the theory of the circulation of the blood, and the
Newtonian theory of gravitation. The labors of the investigators of the
early decades of the eighteenth century, terminating with Franklin's
discovery of the nature of lightning and with the Linnaean
classification of plants and animals, bring us to the close of our second
great epoch; or, to put it otherwise, to the threshold of the modern
period,
I. SCIENCE IN THE DARK AGE
An obvious distinction between the classical and mediaeval epochs
may be found in the fact that the former produced, whereas the latter
failed to produce, a few great thinkers in each generation who were
imbued with that scepticism which is the foundation of the
investigating spirit; who thought for themselves and supplied more or
less rational explanations of observed phenomena. Could we eliminate
the work of some score or so of classical observers and thinkers, the
classical epoch would seem as much a dark age as does the epoch that
succeeded it.
But immediately we are met with the question: Why do no great
original investigators appear during all these later centuries? We have
already offered a part explanation in the fact that the borders of
civilization, where racial mingling naturally took place, were peopled
with semi-barbarians. But we must not forget that in the centres of
civilization all along there were many men of powerful intellect. Indeed,
it would violate the principle of historical continuity to suppose that
there was any sudden change in the level of mentality of the Roman
world at the close of the classical period. We must assume, then, that
the direction in which the great minds turned was for some reason
changed. Newton is said to have alleged that he made his discoveries
by "intending" his mind in a certain direction continuously. It is

probable that the same explanation may be given of almost every great
scientific discovery. Anaxagoras could not have thought out the theory
of the moon's phases; Aristarchus could not have found out the true
mechanism of the solar system; Eratosthenes could not have developed
his plan for measuring the earth, had not each of these investigators
"intended" his mind persistently towards the problems in question.
Nor can we doubt that men lived in every generation of the dark age
who were capable of creative thought in the field of science, bad they
chosen similarly to "intend" their minds in the right direction. The
difficulty was that they did not so choose. Their minds had a quite
different bent. They were under the spell of different ideals; all their
mental efforts were directed into different channels. What these
different channels were cannot be in doubt--they were the channels of
oriental ecclesiasticism. One all-significant fact speaks volumes here. It
is the fact that, as Professor Robinson[1] points out, from the time of
Boethius (died 524 or 525 A.D.) to that of Dante (1265-1321 A.D.)
there was not a single writer of renown in western Europe who was not
a professional churchman. All the learning of the time, then, centred in
the priesthood. We know that the same condition of things pertained in
Egypt, when science became static there. But, contrariwise, we have
seen that in Greece and early Rome the scientific workers were largely
physicians or professional teachers; there was scarcely a professional
theologian among them.
Similarly, as we shall see in the Arabic world, where alone there was
progress in the mediaeval epoch, the learned men were, for the most
part, physicians. Now the meaning of this must be self-evident. The
physician naturally "intends" his mind towards the practicalities. His
professional studies tend to make him an investigator of the operations
of nature. He is usually a sceptic, with a spontaneous interest in
practical science. But the theologian "intends" his mind away from
practicalities and towards mysticism. He is a professional believer in
the supernatural; he discounts the value of merely "natural" phenomena.
His whole attitude of mind is unscientific; the fundamental tenets of his
faith are based on alleged occurrences which inductive science cannot
admit--namely, miracles. And so the minds "intended" towards the
supernatural achieved only the hazy mysticism of mediaeval thought.
Instead of investigating