“What is toleration? It is the appurtenance of humanity. We are all full of weakness and errors; let us mutually pardon each other our follies—it is the first law of nature.”
Voltaire begins toleration from shared human fallibility: recognizing that everyone is capable of error weakens the claim that disagreement should be answered with persecution.
Source details
A Philosophical Dictionary, article ‘Toleration,’ Section I, Project Gutenberg #35630. Voltaire opens the section by calling toleration an attribute of humanity and urging mutual pardon for human weakness and error, then turns immediately to religious communities trading together without violence. This remains an Enlightenment polemic against religious persecution rather than a modern legal definition or universal empirical law.