Gertrude Himmelfarb

The footnote would seem to be the smallest detail in a work of history. Yet it carries a large burden of responsibility, testifying to the validity of the work, the integrity (and the humility) of the historian, and to the dignity of the discipline.

As liberty of thought is absolute, so is liberty of speech, which is 'inseparable' from the liberty of thought. Liberty of speech, moreover, is essential not only for its own sake but for the sake of truth, which requires absolute liberty for the utterance of unpopular and even demonstrably false opinions.