The concern here as so astutely formulated under Aquinian Ethic has to do with 2 things: the object of an action, and the end of an action. (
1) In short, the action itself must be good, right, and proper, and so must the goal of the action.
In regards to contraception involving the introduction of foreign bodies and materials such as the altering of the female hormonal cycle (birth control) or the addition of synthetic materials (condoms, sponges, diaphragms) the result is a change in the action. It is akin to sodomy or fellatio in that regard though on the face of things much less offensive in casual conversation.
The second problem is the alteration of the end of the act. While this sounds like intention, and in truth is not entirely unrelated, it is not as simple as “are we or are we not attempting to undermine God’s will?” For the end of contraception is and always is separation of husband and wife. I do not mean to refer here to divorce, but the very physical union revealed by scripture, “and the two shall become one flesh” (Mark 10:8) Whether this be in the form of a physical barrier or the form of hormonal manipulation which prevents the woman from being present as God would have her be the end is still that separation. (With respect to b.c. altering her hormonal state it is comparative to getting her drunk to alter her mental state, the goal is to remove the woman from sex)
The Natural Family Planning does not do either of these. It introduces nothing into the act of intimacy which is unnatural and does not alter the natural hormonal state of the woman allowing her to be fully present. The end of Natural Family Planning is not the separation of Husband and Wife, but rather the union of Husband and Wife. Natural Family Planning takes advantage of God’s mercy and grace in the female’s natural cycle. God has granted much time during the month for allowing those who are not able or ready to care for a child to still be fully together in the estate of marriage. It is not a burden or law; it is an opportunity for human beings to enjoy the fruits of God’s grace of marriage in spite of a sinful and fallen world which sees poverty and circumstance hindering the prudence in procreation. The alternative would be a marriage which sees a fallen world the victor and the devil successful in his pursuit of separation. Separation of man from his brother, man from God and Husband from Wife.
and he’s Lutheran!
The below is completely irrelevant to the question, but not the topic.
It seems incredibly odd to me that Aquinas using the model of Aristotle has to come up with a gigantic system of “sin ranking.” Then again, perhaps it is not so odd since your primary use of the law is not to reveal the depth of one’s sin, his total depravity and reliance on a savior, the savior, Jesus Christ. You use the law as a ladder by which one may attempting to stand upright in the face of a truly Holy God. Yet all your good deeds will be as filthy rags before the Lord and the law will not make you righteous. If you were truly concerned about convicting people in their sins and showing them the blackness in their hearts you could do much better:
The husband is the Glory of a woman. It is he who provides her children, her redemption. The woman who does not want children is either one of two things: untrusting of her God and husband whom God has provided her to provide for her, or ungrateful and despising of her place in creation, and in truth God’s creation. Even you who practice NFP do so because of your untrusting hearts as a consolation which God has provided for He knows how much you love to break His first commandment and elevate the circumstance of the world above your trust in Him. Yet let it also be known that either you have sex and enjoy it, thinking nothing of children and are dismissive of God’s gift, or you have sex thinking only of children and you are certainly not their to please your husband save for anything but your own ends and not in service to him. In the heart of woman there is not one who is intimate with her husband and does not even for a moment fall into one of these two categories upholding both perfectly, while giving thanks to God.
Men you are to love your wife as Christ does the Church. This will be significantly shorter as it needs little proof of explanation. There is not a man alive who does not in the moment of climax become completely turned inwards using his wife for that moment like a “love rag” or blow-up doll. You who have been entrusted with the care of one of God’s most precious and fragile beings in the most vile and violent of ways are no different than the stranger who would use her and throw her away, the difference is you save her for further use.
It is not the addition of a small rubber tube or a little pill which separates Husband and Wife, but the sin and old Adam which must be drowned daily. We are by nature sinful and unclean, not as God creates us, but as the Fall has left us and infects every aspect of our being. Seeing as how it is my heart, my rejection of God and my neighbor (wife), which puts me in need of the grace of my savior which I receive through faith. The presence or absence of contraception changes…nothing.
Thanks!