Humanum genus leads with the presentation of the
Augustinian dichotomy of the two cities, the City of Man and the
City of God. The human race is presented as "separated into two diverse and opposite parts, of which the one steadfastly contends for truth and virtue, the other of those things which are contrary to virtue and to truth. The one is the kingdom of God on earth, namely, the true Church of Jesus Christ... The other is the kingdom of Satan,"
Humanum genus depicted the fundamental doctrine of Freemasonry as naturalism, asserting that this leads to
deism and
Gnosticism. This was seen as driving Freemasons headlong toward a fundamental clash with the teachings of the Church, especially in light of Freemasons' support of separation of church and state by their efforts to enact and enforce civil constitutional obstacles to the establishment of
state churches. It contrasted the idea of
Original sin in Catholic teaching with the hypothesized approach of Freemasonry and naturalist liberals:...human nature was stained by original sin, and is therefore more disposed to vice than to virtue. For a virtuous life it is absolutely necessary to restrain the disorderly movements of the soul, and to make the passions obedient to reason. In this conflict human things must very often be despised, and the greatest labors and hardships must be undergone, in order that reason may always hold its sway. But the naturalists and
Freemasons, having no faith in those things which we have learned by the revelation of God, deny that our first parents sinned, and consequently think that free will is not at all weakened and inclined to evil. On the contrary, exaggerating rather the power and the excellence of nature, and placing therein alone the principle and rule of justice, they cannot even imagine that there is any need at all of a constant struggle and a perfect steadfastness to overcome the violence and rule of our passions. ==Freemasonry condemned==