It is clear that the main tenet of socialism, community of goods, must be utterly rejected, since it only injures those whom it would seem meant to benefit, is directly contrary to the natural rights of mankind, and would introduce confusion and disorder into the commonweal. The first and most fundamental principle, therefore, if one would undertake to alleviate the condition of the masses, must be the inviolability of private property.
Pope Leo XIIIThe liberty of thinking and publishing whatsoever each one likes, without any hindrances, is not in itself an advantage over which society can wisely rejoice. On the contrary, it is the fountainhead and origin of many evils.
Pope Leo XIIIAll Catholics must make themselves felt as active elements in daily political life in the countries where they live. They must penetrate, wherever possible, in the administration of civil affairs; must constantly exert the utmost vigilance and energy to prevent the usages of liberty from going beyond the limits fixed by God's law. All Catholics should do all in their power to cause the constitutions of states and legislation to be modeled on the principles of the true Church.
Pope Leo XIIITo refuse any bond of union between man and civil society, on the one hand, and God the Creator and consequently the supreme Law-giver, on the other, is plainly repugnant to the nature, not only of man, but of all created things; for, of necessity, all effects must in some proper way be connected with their cause; and it belongs to the perfection of every nature to contain itself within that sphere and grade which the order of nature has assigned to it, namely, that the lower should be subject and obedient to the higher.
Pope Leo XIII