des
mathematics) they made most progress. When there were so few
demonstrated facts to work upon, there was the widest room for
speculation. Now to suppress a number of rival theories in favour of one
is a very different thing from suppressing whole systems of established
facts. If one school of astronomers holds that the earth goes round the
sun, another that the sun goes round the earth, but neither is able to
demonstrate its proposition, it is easy for an authority, which has
coercive power,

[250] to suppress one of them successfully. But once it is agreed by all
astronomers that the earth goes round the sun, it is a hopeless task for
any authority to compel men to accept a false view. In short, because
she is in possession of a vast mass of ascertained facts about the
nature of the universe, reason holds a much stronger position now than
at the time when Christian theology led her captive. All these facts are
her fortifications. Again, it is difficult to see what can arrest the
continuous progress of knowledge in the future. In ancient times this
progress depended on a few; nowadays, many nations take part in the
work. A general conviction of the importance of science prevails to-day,
which did not prevail in Greece. And the circumstance that the advance
of material civilization depends on science is perhaps a practical
guarantee that scientific research will not come to an abrupt halt. In
fact science is now a social institution, as much as religion.

But if science seems pretty safe, it is always possible that in
countries where the scientific spirit is held in honour, nevertheless,
serious restrictions may be laid on speculations touching social,
political, and religious questions. Russia has men of science inferior
to none, and Russia has its notorious censorship. It

[251] is by no means inconceivable that in lands where opinion is now
free coercion might be introduced. If a revolutionary social movement
prevailed, led by men inspired by faith in formulas (like the men of the
French Revolution) and resolved to impose their creed, experience shows
that coercion would almost inevitably be resorted to. Nevertheless,
while it would be silly to suppose that attempts may not be made in the
future to put back the clock, liberty is in a far more favourable
position now than under the Roman Empire. For at that time the social
importance of freedom of opinion was not appreciated, whereas now, in
consequence of the lo