3. But, although we have not omitted often to proscribe and reprobate the chief errors of this kind, yet the cause of the Catholic Church, and the salvation of souls entrusted to us by God, and the welfare of human society itself, altogether demand that we again stir up your pastoral solicitude to exterminate other evil opinions, which spring forth from the said errors as from a fountain. Which false and perverse opinions are on that ground the more to be detested, because they chiefly tend to this, that that salutary influence be impeded and (even) removed, which the Catholic Church, according to the institution and command of her Divine Author, should freely exercise even to the end of the world--not only over private individuals, but over nations, peoples, and their sovereign princes; and (tend also) to take away that mutual fellowship and concord of counsels between Church and State which has ever proved itself propitious and salutary, both for religious and civil interests.¹

For you well know, venerable brethren, that at this time men are found not a few who, applying to civil society the impious and absurd principle of "naturalism," as they call it, dare to teach that "the best constitution of public society and (also) civil progress altogether require that human society be conducted and governed without regard being had to religion any more than if it did not exist; or, at least, without any distinction being made between the true religion and false ones." And, against the doctrine of Scripture, of the Church, and of the Holy Fathers, they do not hesitate to assert that "that is the best condition of civil society, in which no duty is recognized, as attached to the civil power, of restraining by enacted penalties, offenders against the Catholic religion, except so far as public peace may require." From which totally false idea of social government they do not fear to foster that erroneous opinion, most fatal in its effects on the Catholic Church and the salvation of souls, called by Our Predecessor, Gregory XVI, an "insanity," ² viz., that "liberty of conscience and worship is each man's personal right, which ought to be legally proclaimed and asserted in every rightly constituted society; and that a right resides in the citizens to an absolute liberty, which should be restrained by no authority whether ecclesiastical or civil, whereby they may be able openly and publicly to manifest and declare any of their ideas whatever, either by word of mouth, by the press, or in any other way." But, while they rashly affirm this, they do not think and consider that they are preaching "liberty of perdition;" ³ and that "if human arguments are always allowed free room for discussion, there will never be wanting men who will dare to resist truth, and to trust in the flowing speech of human wisdom; whereas we know, from the very teaching of our Lord Jesus Christ, how carefully Christian faith and wisdom should avoid this most injurious babbling." ⁴