When we speak of tolerance we necessarily refer to evil of some sort. In the matter of truth or untruth we are said to tolerate what is untrue, or what we think to be untrue. In the matter of right or wrong, we are said to tolerate what is wrong, or what we think to be wrong. If one says that he is tolerant of that in another which he himself believes to be true or right, he speaks as one who does not understand what he says. It is the same as saying that he is tolerant of his own convictions; in fact, that he tolerates himself. One is said to be tolerant of that in another which he thinks to be erroneous or wrong. Now, every principle which a man holds is a law to him. He may be mistaken; his principles may be false; but whilst he holds them as his principles he cannot under pain of inconsistency disown them in word or deed. No man has proprietary rights in principles. One has no right to compromise them. One may not barter them away, may not make them the basis of a policy of give and take. To do so would be to treat them not as principles but as mere opinions. Principles are things to stand on, not things to play with as with pawns on a chessboard. He who, whilst he professes some principle of belief or conduct in religious or civil life, is ready to agree with his neighbour in the opposite shows little regard for truth and little sense of duty. He who for the sake of some convenience is prepared to play with his principles has practically no principles at all. Such is one who professes universal toleration, although no person would be more pained at being thought an unprincipled man. It is a logical necessity for everyone to be intolerant of principles opposed to his own. In matters of mere _opinion_ one may be, and ought to be, tolerant of the opinions of others, since in face of those opinions he cannot claim an objective certainty for his own. Let us illustrate this. A rationalist who denies the existence of any higher than natural causes cannot admit any event to be miraculous. He may ascribe it to some hypothetical natural cause, or he may have no cause to assign; but he cannot on principle assign a supernatural cause, for the simple reason that he ignores anything above the natural forces which come within the sphere of experience. Thus the rationalist who claims tolerance as his characteristic virtue is intolerant of any doctrine which supposes the supernatural. He must be so, or he lets the ground go from under his feet. Again, the Protestant on his principle of private judgment must be intolerant of any doctrine which supposes an infallible authority on earth claiming a divine commission to teach us the meaning of divinely Revealed Truths. A Catholic who believes in a Church of divine institution, one, visible, infallible, cannot be tolerant of a doctrine which makes different Churches belong by equal right to Christianity, each whilst conflicting with the others claiming Christ for its Founder. For the same