Socialism, Communism, clandestine societies, Bible societies... pests of this sort must be destroyed by all means.
Pope Pius IXIt is error to believe that Every man is free to embrace and profess that religion which, guided by the light of reason, he shall consider true.
Pope Pius IXNow you know well that the most deadly foes of the Catholic religion have always waged a fierce war, but without success, against this Chair [of St. Peter]; they are by no means ignorant of the fact that religion itself can never totter and fall while this Chair remains intact, the Chair which rests on the rock which the proud gates of hell cannot overthrow and in which there is the whole and perfect solidity of the Christian religion.
Pope Pius IX[Dr. Constain James] refuted so well the aberrations of Darwinism.... [A system] which is repugnant at once to history, to the tradition of all people, to exact science, to observed facts, and even to reason itself, would seem to need no refutation. But the corruption of this age, the machinations of the perverse, the danger of the simple, demand that such fancies, altogether absurd though they are, should - since they borrow the mask of science - be refuted by true science.
Pope Pius IXThese enemies of divine revelation extol human progress to the skies, and with rash and sacrilegious daring would have it introduced into the Catholic religion as if this religion were not the work of God but of man, or some kind of philosophical discovery susceptible of perfection by human efforts.
Pope Pius IX