CHAPTER CXXVI—That not all Sexual Intercourse is Sin

THE members of the body being the instruments of the soul, the end of every member is the use of it, as in the case of any other instrument. But there are members of the body the use of which is for the intercourse of the sexes: that therefore is their end. But that which is the end of any natural thing cannot be in itself evil, because the things of nature are ordinances of divine providence. Therefore the intercourse of the sexes cannot be in itself evil.

3. Natural inclinations are put into things by God, who is the prime mover of all. Therefore it is impossible for the natural inclination of any species to be directed to an object in itself evil. But in all full-grown animals there is a natural inclination to sexual union, which union therefore cannot be in itself evil.

4. That without which something good and excellent cannot be, is not in itself evil.⁷⁷¹⁷⁷¹It is not ‘evil in itself,’ that is, not absolutely, universally, and under all circumstances. Neither is it universally and under all circumstances good; but where there is a good, of nature established, there is somehow, and under some conditions, a natural and good way of attaining to that good; and where there is for all men but one way of attaining that good, the said way cannot be evil for ever and for all. But the perpetuity of the species in animals is not preserved except through generation, which is of sexual intercourse.

Hence it is said: She sinneth not, if she marry (1 Cor. vii, 36).

Hereby is excluded the error of those who totally condemn marriage, which some do because they believe that temporal things proceed not from a good but from an evil principle.⁷⁷²⁷⁷²He means the Manicheans. There is a Manichean sentiment lurking in some souls, as though the intercourse of the sexes were a necessary evil, only permissible because inevitable, but a bad act in itself. They should take to heart St Augustine’s saying: “He does not perfectly believe in Thee, O Lord, who objects to any creature that Thou hast made.”