ucceeded 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