Most beliefs about nature and man, which were
not founded on scientific observation, have served directly or
indirectly religious and social interests, and hence they have been
protected by force against the criticisms of persons who have the
inconvenient habit of using their reason. Nobody minds if his neighbour
disbelieves a demonstrable fact. If a sceptic denies that Napoleon
existed, or that water is composed of oxygen and hydrogen, he causes
amusement or ridicule. But if he denies doctrines which cannot be
demonstrated, such as the existence of a personal God or the immortality
of the soul, he incurs serious disapprobation and at one time he might
have been put to death. Our mediaeval friend would have only been called
a fool if he doubted the existence of Constantinople, but if he had
questioned the significance of comets he

[18] might have got into trouble. It is possible that if he had been so
mad as to deny the existence of Jerusalem he would not have escaped with
ridicule, for Jerusalem is mentioned in the Bible.

In the Middle Ages a large field was covered by beliefs which authority
claimed to impose as true, and reason was warned off the ground. But
reason cannot recognize arbitrary prohibitions or barriers, without
being untrue to herself. The universe of experience is her province, and
as its parts are all linked together and interdependent, it is
impossible for her to recognize any territory on which she may not
tread, or to surrender any of her rights to an authority whose
credentials she has not examined and approved.

The uncompromising assertion by reason of her absolute rights throughout
the whole domain of thought is termed rationalism, and the slight stigma
which is still attached to the word reflects the bitterness of the
struggle between reason and the forces arrayed against her. The term is
limited to the field of theology, because it was in that field that the
self-assertion of reason was most violently and pertinaciously opposed.
In the same way free thought, the refusal of thought to be controlled by
any authority but its own, has a definitely theological reference.
Throughout

[19] the conflict, authority has had great advantages. At any time the
people who really care about reason have been a small minority, and
probably will be so for a long time to come. Reason's only weapon has
been argument. Authority has employed physical and moral violence, legal
coercion and social displeasure