Human beings can discover these obligations by their own reasoning powers, although the Almighty has included many of them in His revelation, such as 'Thou shalt not kill.
A human being can direct his faculties of soul and of body to the purposes intended by the Creator, or he can distort them to other ends.
And on the way he chooses to employ them depends the morality of his actions.
Each organ has its proper purpose, each faculty its proper function.
Now it is certainly the will of the Creator who adapted these vital powers to definite ends that they should operate toward the attainment of these ends.
And since the reproductive function is so vital to the upkeep of the race, and since any exception to this law would be multiplied indefinitely, every act of contraceptive frustration is a gravely immoral act, or, in Catholic terminology, a mortal sin.
To quote the terse phrase of Pope Pius XI in his Encyclical on Christian Marriage: 'Any use whatsoever of matrimony exercised in such a way that the act is deliberately frustrated in its natural power to generate life is an offense against the law of God and of nature, and those who indulge in such are branded with the guilt of a grave sin.' II I have said that contraception is opposed to the chief purpose of sexual intercourse.
However, the necessary limitations of this article compel me to assume that my readers are sufficiently acquainted with at least one argument proving that there is a God whose laws are binding on all mankind.
In common with most Protestants and Jews, Catholics hold that the Almighty has made known to the human race through inspired prophets certain doctrines that transcend man's natural intellectual powers and certain precepts that exceed his natural duties.
Certainly there are other ends to which nature ordains conjugal relations, especially the alleviation of sexual craving and the fostering of a deep and abiding love between husband and wife.
It is absurd to imagine that the Catholic Church regards conjugal coition as nothing more than a physical medium for the generation of offspring.