A large vocabulary of related concepts has been used to define and promote toleration. If, as mentioned above, religion created many of the disputes that lead to persecution, it also produced many concepts that can lead toward toleration. Irenicism (the seeking of peace), the pursuit of concord, comprehension, latitudinarianism, and basic agreement on fundamentals have been policies of many theologians and churchmen. Where these policies recognize that we may never approve of everything the other thinks or does, they promote toleration. Where they imply that someday we will all agree, they go beyond it.
Other terms that have both religious and secular meanings are relevant. Mercy and charity may inspire one to tolerate. Patience is close to the root meaning of the Latin word, helping one endure what one disapproves. Humility, modesty, and skepticism about one's own knowledge of what is right may incline one to tolerate others even when one disagrees with them. Indulgence can mean allowing something that one could prevent. Compromise may mean conceding some points in order to gain others, tolerating the loss of the conceded points.
High-minded philosophical principles can lead toward toleration. Belief in the autonomy and independence of other people can justify leaving them alone even when one does not like what they are doing. Principles of impartiality and neutrality may make a state stay out of religious or other quarrels. Of course, not just any principle will do: most persecution is justified by principle as well.
Toleration has not always been the result of principle. It can come about for purely practical reasons because of exhaustion, impotence, or impasse. It can be the result of politique calculation that hostility does not pay. Swiss physician and theologian Thomas Erastus (1524–1583) gave his name to Erastianism, a term for state supremacy and policies that enforce toleration in order to maintain political stability and prevent religious fighting. Gag orders and decrees prohibiting further debate have often been used to silence contending parties in the hopes of reaching a modicum of mutual toleration.
Liberty of conscience and freedom of religion are policies that sometimes overlap with toleration and sometimes go beyond it. Liberty of conscience usually means that everyone may think what they like, and no one will inquire into what they think. But this is compatible with suppressing public expression of what one thinks. On the one hand, this may be better than regimes in which "thought police" are constantly monitoring people's ideas; on the other, it is not as free as forms of toleration that permit expression. Freedom of religion often means that one can choose among two or more established religions, but it sometimes also implies that one must choose one of the available religions. It may not tolerate rejection of all religion.