Pagans may have, heretics cannot have, the same principles as Catholics; if the latter have the same, they are not real heretics, but in ignorance. Principle is a better test of heresy than doctrine. Heretics are true to their principles, but change to and fro, backwards and forwards, in opinion; for very opposite doctrines may be exemplifications of the same principle. Thus the Antiochenes and other heretics sometimes were Arians, sometimes Sabellians, sometimes Nestorians, sometimes Monophysites, as if at random, from fidelity to their common principle, that there is no mystery in theology. Thus Calvinists become Unitarians from the principle of private judgment. The doctrines of heresy are accidents and soon run to an end; its principles are everlasting. This, too, is often the solution of the paradox "Extremes meet," and of the startling reactions which take place in individuals; viz., the presence of some one principle or condition, which is dominant in their minds from first to last. If one of two contradictory alternatives be necessarily true on a certain hypothesis, then the denial of the one leads, by mere logical consistency and without direct reasons, to a reception of the other. Thus the question between the Church of Rome and Protestantism falls in some minds into the proposition, "Rome is either the pillar and ground of the Truth, or she is Antichrist;" in proportion, then, as they revolt from considering her the latter are they compelled to receive her as the former. Hence, too, men may pass from infidelity to Rome, and from Rome to infidelity, from a conviction in both courses that there is no tangible intellectual position between the two. Protestantism, viewed in its more Catholic aspect, is doctrine without active principle; viewed in its heretical, it is active principle without doctrine. Many of its speakers, for instance, use eloquent and glowing language about the Church and its characteristics: some of them do not realize what they say, but use high words and general statements about "the faith," and "primitive truth," and "schism," and "heresy," to which they attach no definite meaning; while others speak of "unity," "universality," and "Catholicity," and use the words in their own sense and for their own ideas. 4.