Whenever the church has spoken of contraception as an intrinsic evil, it has always spoken of it in the context of the** conjugal act** which is intended do bring about the union of the spouses. Since rape falls outside this category, it is morally permissible for a rape victim to take the morning after pill given the fact that conception hasn’t yet occurred.
No, the Church’s teaching on contraception does not just apply to the conjugal union.
The reason why is that it is based on the natural law. To understand the natural law, you must first understand what is meant by
nature.
Nature refers to a realm of beings which we ourselves don’t “make”. A flower is a natural being; a car is not.
This realm has its own teleology and is independent of human will. It is governed by natural ends which apply to every instance of a “natural” activity.
Thus, the natural ends of sexual activity, the unitive and the procreative, are “present” in every act of sexual intercourse, not just those in marriage.
This is what is being assumed, not just in the Summa, but in many other works of moral theology over the centuries.
This is particularly true of the Theology of the Body where Blessed John Paul II talks about the “language” of the body or the “nuptial” meaning of the body. Emphasis is on “body”. As a good phenomenologist, he knows that the body has its own intentionality which human subjectivity should “coincide with”. TOB is not something radically new but is a recapitulation of the traditional teaching about “natural ends”.
But there can be a “gap” between natural ends and human intentions in the sex act. A sex act can be a “lie”, a “falsehood”, as TOB points out repeatedly. This does not mean that the natural ends are not “present”; no, they remain operative. It’s really a case of the body going in one direction and the human person going in an opposite direction.