designates a class of rules or principles
of which the social utility has been found by experience to be paramount
and which are recognized to be so important as to override all
considerations of immediate expediency. And social utility is the only
test. It is futile, therefore, to say to a Government that it acts
unjustly in coercing opinion, unless it is shown that freedom of opinion
is a principle of such overmastering social utility as to render other
considerations negligible. Socrates had a true instinct in taking the
line that freedom is valuable to society.

The reasoned justification of liberty of thought is due to J. S. Mill,
who set it forth in his work On Liberty, published in 1859. This book
treats of liberty in general, and attempts to fix the frontier of the
region in which individual freedom should be considered absolute and
unassailable. The second chapter considers liberty of thought and
discussion, and if many may think that Mill unduly minimized the
functions of society, underrating its claims as against the individual,
few will deny the justice of the chief arguments or question the general
soundness of his conclusions.

[237]

Pointing out that no fixed standard was recognized for testing the
propriety of the interference on the part of the community with its
individual members, he finds the test in self-protection, that is, the
prevention of harm to others. He bases the proposition not on abstract
rights, but on "utility, in the largest sense, grounded on the permanent
interests of man as a progressive being." He then uses the following
argument to show that to silence opinion and discussion is always
contrary to those permanent interests. Those who would suppress an
opinion (it is assumed that they are honest) deny its truth, but they
are not infallible. They may be wrong, or right, or partly wrong and
partly right. (1) If they are wrong and the opinion they would crush is
true, they have robbed, or done their utmost to rob, mankind of a truth.
They will say: But we were justified, for we exercised our judgment to
the best of our ability, and are we to be told that because our judgment
is fallible we are not to use it? We forbade the propagation of an
opinion which we were sure was false and pernicious; this implies no
greater claim to infallibility than any act done by public authority. If
we are to act at all, we must assume our own opinion to be true. To this
Mill acutely replies: "There is