Pufendorf: On the Duty of Man and Citizen according to Natural Law

1. The first of the adventitious states in which a man is set by some prior human act is marriage. Marriage may be called the first example of social life and at the same time the seed-bed of the human race.

2. And first of all it is a settled point that the burning attraction of the sexes to each other has not been designed by the Creator in His great wisdom for the satisfaction of empty pleasure; for taken by itself it was bound to generate extreme nastiness and disorder in the human race. But it has been given to enhance relations between man and wife and to encourage them to put themselves to the trouble of having children and of bearing the difficulties which attend their birth and upbringing.

It follows from this that any employment of the genital members which deviates from these purposes is repugnant to natural law. Under this heading come forbidden lust directed towards a different species or towards persons of the same sex; any kind of filthy impurity; and all extra-marital intercourse, whether by mutual consent or against the woman's will.

3. The Obligation to contract marriage may be considered either with respect to the human race as a whole or with respect to individuals.

In the first respect the Obligation is that the propagation of the human race must absolutely not proceed by way of casual and promiscuous intercourse. It should always be bound by the laws of matrimony and therefore only practised within marriage. Without this a decent and well-ordered society among men and the development of civil life are inconceivable.

In the second respect individuals are obliged to enter into marriage when a suitable opportunity occurs. This is determined not only by age and the capacity to beget, but also by the chance of a suitable match and the capacity to support the wife and any children there may be; also by whether the man is fit to take on the role of head of the family. An exception is made for anyone who has the temperament to lead a chaste life as a Single person, and feels that he can achieve more good for the human race or for his country by not marrying than by marrying, especially when there is no fear of a shortage of children.