if he did not happen to meet an evil spirit, it did not occur to him,
unless he was a prodigy, that there was a distinction between the two
statements; he would rather have argued, if he argued at all, that as
his tribesmen were right about the bears they were sure to be right also
about the spirits. In the Middle Ages a man who believed on authority
that there is a city called Constantinople and that comets are portents
signifying divine wrath, would not

[17] distinguish the nature of the evidence in the two cases. You may
still sometimes hear arguments amounting to this: since I believe in
Calcutta on authority, am I not entitled to believe in the Devil on
authority?

Now people at all times have been commanded or expected or invited to
accept on authority alone—the authority, for instance, of public
opinion, or a Church, or a sacred book—doctrines which are not proved or
are not capable of proof. 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