Liber III, Pars II — Quomodo ius gentium, et ius positivum a iure naturali habet esse distinctum. Cap. XXV.

Liber III, Pars II — Quomodo ius gentium, et ius positivum a iure naturali habet esse distinctum. Cap. XXV.

All the distinctions about law made by the Philosopher, which we touched on in the previous chapter, were twofold. Of these, one part was contained under natural law, and the other under civil or positive law. However, the jurists added a third part, which is the law of nations; according to this way of speaking, a fourth part can be added, which is the law of animals. To clarify this, it should be noted that man, as he is man and considered according to his proper nature, differs from other animals; but as he is an animal and according to the common nature, he is similar to them. If, therefore, these things are of natural law, to which we have a natural impulse and inclination: such a natural impulse either follows our nature, as we are human, and as we differ from other animals, and this law is called the law of nations. But if that inclination follows our nature, as we agree with other animals, then it is said to be natural law. Therefore, in the Institutes, where these things are handed down, it is said that natural law is what nature has taught all animals. However, this law (as it is written there) is not proper to the human race, but to all animals that are born in heaven, on earth, and in the sea. Therefore, according to this, the natural law includes the union of man and woman, the procreation of offspring, and the education of children. For if a person is naturally inclined to this, and if such an impulse follows human nature, it does not follow it as human, but as animal, and as it agrees with other animals; for animals also are naturally inclined to join males with females, to generate offspring, and to nurture and care for them. The law of nations, however, is said to be that which is not common to other animals: but it is common to all humankind. From this, therefore, nearly all contracts are introduced, such as purchase, sale, lease, and hire, and other such matters, without which human society cannot adequately sustain itself for life. Thus, mutual agreements and deposits, which also serve human life in which other animals do not participate, are included under this law of nations. Therefore, the law of nations is a certain natural law of contracts. That law, therefore, which nature has taught all animals, and which follows our natural inclination to communicate with other animals, is said to be natural in relation to the law of nations. For if the statements made in the preceding chapter are considered, natural law is something common, something known, and something immutable. The more a law is common to all, compared to the law of nations, the more it deserves to be called natural law. Thus, the law that all animals are taught and in which all animals participate is more common than the law of nations, and consequently it is better known, because it is more familiar to us. The more universal something is, the more it is known to our understanding, and it first falls into our perception. This law is also more immutable because the rules of law, the more they apply to specific matters, the more defects they incur, and in many cases they are not to be observed, and they undergo greater changes; therefore, this law is rightly called natural in relation to the law of nations. Seeing how the law of nations differs from natural law, it can easily be seen how the law of animals differs from natural law. For just as human nature, inasmuch as it is animal, agrees with the natures of other animals, so inasmuch as it lives and is a certain being, it agrees with plants, and with other substances, and with all beings. Therefore, natural inclination can follow the nature of man either as man is, or as it agrees with other animals, or as it agrees with all beings. For man naturally desires to be preserved in existence, which all other beings also desire; he naturally desires to produce children, to raise offspring, which other animals also long for; he also naturally desires to live in society according to rightful agreements and conventions, which is proper only to man among animals. If therefore the rules of actions are based on what a person naturally desires, which is to exist, then such rules can be considered part of natural law, as human nature is a certain essence that aligns with all beings. But if those rules are derived from what a person naturally desires to produce and raise children, then they can also be considered part of natural law, as natural law is said to be what nature has taught all animals. However, if they are based on how a person naturally desires to live in society according to rightful agreements and contracts, then it will be part of natural law, as natural law is contracted to the law of nations, which is proper to the human race alone. From this, it is clear that since nature has taught all animals, this kind of law, which nature has taught all animals, is not as natural as that law which follows the inclination of our nature; for we not only share with other animals, but also agree with all beings: for this kind of law is more known and common than that: for to desire good and to exist, and to flee from evil and non-existence, is more a part of natural law than to desire to procreate children and to nurture offspring. Therefore, this order will be that the law following our nature, as we desire to exist and to do good, is natural in relation to the law of animals, or in relation to the law which nature has taught all animals: likewise, this kind of law is natural in relation to civil law, which is simply established. Thus, there are three things that are in some way part of natural law, according to which inclination follows our nature: for if that inclination follows our nature as human, the law of nations is derived from it. If it is as it agrees with other beings, then that law, which nature has taught all animals, has its being. But if it is as it agrees with all beings, then that law, which is called natural by antonomasia, has its being. The desire to exist and to do good, and to flee from non-existence and evil, which we naturally crave, is part of natural law; from this, all other rules and laws, whether natural or civil, take their origin and are founded upon it, for in all things there is either the pursuit of good or the avoidance of evil. However, to discuss this more broadly requires a different matter. For now, it suffices to know how the law of nations, the law of animals, and even civil law differ from natural law.