If mankind minus one were of one opinion, then mankind is no more justified in silencing the one than the one--if he had the power--would be justified in silencing mankind.

Mill writes this in the opening chapter of *On Liberty* (1859), in the course of arguing for robust freedom of thought and discussion. He is responding to the danger of “social tyranny” as well as legal censorship: even in constitutional states, public opinion and majorities can suppress dissenting voices. The line appears as Mill sets out the case that silencing an opinion is a peculiar wrong because it deprives not only the speaker but the public—either of a true view, or of the clearer understanding that comes from contesting error. The formulation dramatizes the asymmetry between majority power and individual rights by imagining the majority as “mankind minus one.”

The sentence states a principle of moral equality in matters of expression: numbers do not convert coercion into justice. Even if nearly everyone agrees, the lone dissenter retains the same claim not to be forcibly silenced as the majority would claim against a tyrannical individual. Mill’s deeper point is epistemic and civic: because humans are fallible, suppressing dissent risks extinguishing truth; and even when dissent is mistaken, open contestation keeps prevailing beliefs from becoming “dead dogma.” The quote thus anchors Mill’s liberal defense of free speech in both individual rights and the collective benefits of intellectual pluralism.

1) “If all mankind minus one were of one opinion, mankind would be no more justified in silencing that one person, than he, if he had the power, would be justified in silencing mankind.”
2) “If all mankind minus one were of one opinion… no more justified in silencing the one…” (common abridged form)
3) “If all mankind, except one, were of one opinion…” (alternate wording in some editions/quotations)