From Mr Joseph Shaw SIR I enjoyed Quentin de la Becloyere's interview with Professor John Marshall (Features, July 18), a member of the commission which vainly recommended to Pope Paul VI that he change the Church's teaching on contraception. Particularly amusing was the suggestion that the faithful have not "received" this teaching, as if Christ should, when faced by a rejection of his teaching by many of his followers (John 6:66), have reconsidered it, or as if St Paul, anticipating an audience who "would not endure sound doctrine" (2 Timothy 4:3), would recommend giving them unsound doctrine instead. It is one of the most remarkable works of providence in modern times that Paul VI was able to overcome the pressure from this commission, and other sources. to exercise faithfully his role, which was that of a teacher, not a weathervane.
Two well-known and closely related arguments are relevant here. First, the unitive value of the sexual act in marriage is dependent upon its procre ative potential, since it is in becoming, or being open to becoming, a single procreative principle that the couple is drawn together. Second, sexual selfgiving in marriage is incomplete when procreation is artificially excluded, since in that case one or both the partners is holding something fundamental back: he or she is not giving him or herself wholly, but excluding his or her fertility.
These arguments, which are at least implicit in Humane Vitae sections eight and nine, have been set out with great clarity since then, notably in the work of Karol Wojtyla, both before and after his election as Pope John-Paul II. Far from it being the case, as Professor Marshall affects to think, that there are no Natural Law arguments for the Humane Vitae position, I am not aware of any other arguments, compatible with artificial contraception, which explain the unitive role of the marital act.
Yours faithfully, JOSEPH SHAW Oxford