With regard to intrinsically evil acts, and in reference to contraceptive practices whereby the conjugal act is intentionally rendered infertile, Pope Paul VI teaches: “Though it is true that sometimes it is lawful to tolerate a lesser moral evil in order to avoid a greater evil or in order to promote a greater good, it is never lawful, even for the gravest reasons, to do evil that good may come of it (cf. Rom 3:8) – in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general”. (VS 80)

In teaching the existence of intrinsically evil acts, the Church accepts the teaching of Sacred Scripture. The Apostle Paul emphatically states: “Do not be deceived: neither the immoral, nor idolaters, nor adulterers, nor sexual perverts, nor thieves, nor the greedy, nor drunkards, nor revilers, nor robbers will inherit the Kingdom of God” (1 Cor 6:9-10).

If acts are intrinsically evil, a good intention or particular circumstances can diminish their evil, but they cannot remove it. They remain “irremediably” evil acts; per se and in themselves they are not capable of being ordered to God and to the good of the person. “As for acts which are themselves sins (cum iam opera ipsa peccata sunt), Saint Augustine writes, like theft, fornication, blasphemy, who would dare affirm that, by doing them for good motives (causis bonis), they would no longer be sins, or, what is even more absurd, that they would be sins that are justified?”.

Consequently, circumstances or intentions can never transform an act intrinsically evil by virtue of its object into an act “subjectively” good or defensible as a choice. (VS 81)

Furthermore, an intention is good when it has as its aim the true good of the person in view of his ultimate end. But acts whose object is “not capable of being ordered” to God and “unworthy of the human person” are always and in every case in conflict with that good. Consequently, respect for norms which prohibit such acts and oblige semper et pro semper, that is, without any exception, not only does not inhibit a good intention, but actually represents its basic expression. (VS 82)