of necessity,”14 or—with a stronger emphasis on the person’s ability of performing—authority [potestas] as “an active moral power by which some person legitimately and with a moral effect is able to perform a voluntary action.”15 All moral entities are ultimately rooted in natural law conceived as a divine decree imposed in accordance with created human nature and immutable as long as human nature remains unchanged according to divine will.16 Thus the contents of natural law must be learned through a consideration of human nature, its desires and conditions, while the obligatory force of the law is solely derived from the divine will.17
Among the principles of the natural law system only two are considered as axioms, whose “certainty and necessity, flows from reason itself, without the perception of particulars,” namely, the axiom of imputability of voluntary actions “that may be directed according to a moral norm,”18 and the axiom of the obligatory nature of norms in proportion to the authority of the person prescribing them.19 While imputability and the prescriptive nature of norms express formal requirements of morality, the material content of natural law is exclusively grounded in the other kind of principles—the Observations—whose certainty “is perceived from the comparison and perception of particulars uniformly corresponding to one another.”20 They concern the human intellect and its faculty of (moral) judgment (Observ. 1), the liberty of the will (Observ. 2), the natural sociability of man (Observ. 3), the harmony of self-preservation and society (Observ. 4), and the necessity to establish human sovereignty in particular societies (Observ. 5). Here Pufendorf mainly draws on the natural law writings of Hugo Grotius and Thomas Hobbes, whom he mentions in his preface. The basic anthropology contained in the observations emerges mainly from a critical discussion of their natural law doctrines, resulting in an effort to reconcile Hobbes’s egoism and concept of human society as an artifact with Grotius’s doctrine of social appetite conceived as the telos of a rational and social nature.
As a universal science of “law and equity, . . . by virtue of which the duties of all men whatsoever . . . are governed,”21 the natural law system of the Elements also embraces matters belonging to international law, reflecting its growing importance in the emerging system of sovereign national states. In line with the Hobbesian identification of natural and international law,22 the Elements does not treat these matters as a separate body of law but subsumes them under the general definitions of moral entities comprising items of natural, civil, and international law. Thus the scholion to Def. 5 of a moral thing (§§7–10) also discusses a subject most pressing for Pufendorf’s contemporaries, the freedom of the sea. As the citations of the relevant parts of De jure naturae et gentium reveal, Pufendorf was well acquainted with the writings of Hugo Grotius, John Selden, and Alberico Gentili in that field.23 According to Pufendorf’s natural law theory, property originates in negative community, that is to say, the natural world is equally open to everyone and it requires contractual consent for anything to be appropriated; but he leaves the concrete manner of consenting to be determined by the people involved. On this basis Pufendorf argues for the possibility of exclusive dominion of parts of the sea, especially in coastal areas and straits. He rejects the Grotian view that the “unbounded” nature of the ocean argues for the impossibility of its exclusive dominion (De jure belli ac pacis, 2, 2, §3). This issue and that of the inviolability of legates (Def. 13, §26) are closely related to the actual circumstances under which the Elements was written. As a member of the Swedish diplomatic mission in Copenhagen in 1657–58, Pufendorf was arrested by the Danes when the Swedes suddenly reopened the war against Denmark that had been suspended by the peace of Roskilde in 1658, a war mainly fought for the control of the Sund, the strait between Sweden and Denmark.24
Apart from the Euclidean methodology shown in the arrangement of definitions, principles, and propositions, the “geometric” nature of the Elements also manifests itself in a model illustrating moral degrees by spatial magnitudes. The basic idea of the “moral sphere” introduced in the scholion to Def. 18 (The quantity of moral actions is the estimative measure by which they are said to be of a certain degree) is to illustrate “divergence from law” by an angle, the first side of which represents the thing commanded by law, the second side the (actual or intended) action, and the angular distance the degree of fault. The indefinite number of possible deviations from law according to intention or execution corresponds (in the geometric model) to the infinite number of lines (and of the angles formed by them) intersecting in any point. So the complete quantitative aspect of moral actions is best illustrated by a sphere whose center forms the point of intersection of the sides of all moral angles. God is “conceived of as seated at the centre of the moral sphere, . . . as though in our heart, from which proceeds . . . the radius of the law . . ., the finger, as it were, of God, pointing out precisely to us the polar region,” while he leaves “behind Him, as though He had turned his face away from it, the antipolar district . . ., opposite to this.”25 Of the sphere’s three cardinal circles, the horizon represents the radius of execution and the meridian the radius of intention, while the equator separates the polar hemisphere of enjoined actions from the antipolar hemisphere of forbidden actions. An appendix added to the Jena edition of 1669 (and all subsequent editions) enlarges the moral sphere by further concentric orbs arranged like the orbits of the Copernican system and representing the objects of moral actions (and the respective commandments of the Decalogue). It seems strange that this addition was made in 1669, the year when Pufendorf finished De jure naturae et gentium,26 in which he dropped that geometric illustration of moral quantity and denounced the moral sphere as a product of juvenile subtlety [argutia].27 Already in Pufendorf’s lifetime Erhard Weigel was suspected of being the real author of the appendix.28
In his main work, De jure naturae et gentium, Pufendorf not only dropped the moral sphere and its geometric illustration of moral quantity, but also the Euclidean arrangement according to definitions, principles, and propositions. Though still committed to the program of a demonstrative science of natural law as articulated in the chapter (I.2) on the certainty of the moral sciences, the idea remained programmatic and no longer determined the organization of the book. As the methodological discussions in the Dissertatio de statu hominum naturali (Dissertation on the Natural State of Men) of 1675 and the Eris Scandica (Nordic Strife) of 1686 reveal, the model of demonstration was no longer seen in Euclidean geometry but in contemporary natural science and its method of resolution and composition that combined empirical and deductive procedures.29 Like Hobbes in the preface of De cive, Pufendorf demands in the De statu that the state be considered like a body and explained by a hypothetical reduction to “prime matter,” i.e., the condition of man outside of any society and devoid of arts and institutions, so that the nature, necessity, and advantage of civil society might be understood in terms of this “matter.”30 Accordingly, the doctrine of the natural state that only played a marginal role in the Elements gained a prominent place in De jure naturae et gentium.31 The resolutive-compositive method shows us the “state of single individuals left alone by themselves” [status naturalis in se] as a counterfactual supposition [fictio contrarii] that demonstrates the necessity of social life and introduces “sociality” [socialitas] as the fundamentum of natural law.32 In contrast to the plurality of principles discussed in the second book of the Elements, sociality figures as the unique principle of natural law in De jure naturae et gentium, a principle that “is not only genuine and clear, but also . . . sufficient and adequate [so] that there is no precept of the natural law affecting other men, the basis of which is not ultimately to be sought therein.”33 Although based on experience, it has methodological status as “principle” [principium], for while it corresponds to the hypotheses that the natural sciences gain from experience, once established it serves as the deductive basis for scientific theorems.34 Accordingly, experience that already played a major role in the Elements’ observations as foundation for that work’s anthropology now gained preeminent importance. This is shown in the vast number of citations from manifold sources (ancient and contemporary philosophy, historiography and literature, legal texts, contemporary books of travel) that supplement the systematic approach to natural law by giving examples of concrete moral,