The Concept of Tolerance. There is about tolerance something paradoxical, for it consists, in fact, in permitting something which we know with certainty to be either an evil or an error: permissio negativa mali, as the theologian carefully defines it. Negative, because the permission does not imply either encouragement or approval.

From this definition it follows that tolerance is not, in the strict sense of the word, a virtue. We ought rather to say that the exercise of tolerance is authorized and required by a virtue, on account of some greater good which must be promoted or defended. The ultimate justification for tolerance has to be sought in the reflection of the divine laws governing the world, which human rulers are required to achieve. ‘Human government', says St Thomas, ‘is derived from the divine government, and must imitate it.