ics to inoculation in the eighteenth century was a survival
of the mediaeval view of disease. Chemistry (alchemy) was considered a
diabolical art and in 1317 was condemned by the Pope. The long
imprisonment of Roger Bacon (thirteenth century) who, while he professed
zeal for orthodoxy, had an inconvenient instinct for scientific
research, illustrates the mediaeval distrust of science.

It is possible that the knowledge of nature would have progressed
little, even if this distrust of science on theological grounds had not
prevailed. For Greek science had ceased to advance five hundred years
before Christianity became powerful. After about 200 B.C. no important
discoveries were made. The explanation of this decay is not easy, but we
may be sure that it is to be sought in the

[66] social conditions of the Greek and Roman world. And we may suspect
that the social conditions of the Middle Ages would have proved
unfavourable to the scientific spirit-- the disinterested quest of
facts--even if the controlling beliefs had not been hostile. We may
suspect that the rebirth of science would in any case have been
postponed till new social conditions, which began to appear in the
thirteenth century (see next Chapter), had reached a certain maturity.
Theological prejudice may have injured knowledge principally by its
survival after the Middle Ages had passed away. In other words, the harm
done by Christian doctrines, in this respect, may lie less in the
obscurantism of the dark interval between ancient and modern
civilization, than in the obstructions which they offered when science
had revived in spite of them and could no longer be crushed.

The firm belief in witchcraft, magic, and demons was inherited by the
Middle Ages from antiquity, but it became far more lurid and made the
world terrible. Men believed that they were surrounded by fiends
watching for every opportunity to harm them, that pestilences, storms,
eclipses, and famines were the work of the Devil; but they believed as
firmly that ecclesiastical rites were capable of coping with these
enemies. Some of the

[67] early Christian Emperors legislated against magic, but till the
fourteenth century there was no systematic attempt to root out
witchcraft. The fearful epidemic, known as the Black Death, which
devastated Europe in that century, seems to have aggravated the haunting
terror of the invisible world of demons. Trials for witchcraft
multiplied, and for three hund