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

1. Human actions arise from the will. But the acts of will of an individual are not consistent in themselves; and the wills of different men tend in different directions. For mankind to have achieved order and decency therefore, there must have been some rule to which those wills might conform. For otherwise if each man, amid so much liberty to will and such diversity of inclinations and desires, had done whatever came into his mind without reflective reference to a fixed rule, the result would inevitably have been great confusion among men.

2. This rule is called law [lex]. Law is a decree by which a superior obliges one who is subject to him to conform his actions to the superior's prescript [praescriptum].

3. To understand this definition better, one must answer these questions: what is Obligation? what is its origin? who can incur Obligation, and who can impose Obligation on another? Obligation is commonly defined as a bond of right by which we are constrained by the necessity of making some Performance. That is,

Obligation places a kind of bridle on our liberty, so that, though the will can in fact take different directions it yet finds itself imbued by it with an internal sense (so to speak), so that it is compelled to recognize that it has not acted rightly if the subsequent action does not conform to the prescribed rule. Consequently, if anything bad happens to a man for that reason, he judges that he deserves it, since he could have avoided it by following the rule, as he should have done.

4. There are two reasons why man is fit to incur Obligation: (1) he has a will capable of moving in various directions and so able to conform to the rule; and (2) he is not free from the authority of a superior. For there is no expectation of free action where an agent's powers are tied by nature to a uniform mode of behaviour; and it is pointless to prescribe a rule to one who can neither understand nor conform to it.