Refraining from acting against that which is disapproved of, or politically opposed, or alien. Toleration in religious matters is one of the central planks of the modern democratic state: Locke’s Letter on Toleration (1689) is the basic authority, although Locke himself exempted Roman Catholics from the umbrella of protection, on the grounds that their primary allegiance would be to the Church and not to the government. The central philosophical problem is understanding how a principle of toleration can coincide with genuine moral and religious conviction.