This introductory chapter identifies the key questions, themes and debates addressed within the Handbook on Natural Law and Human Rights, and provides a conceptual overview of and integrated perspective on its contents. In particular, it argues that there is a perennial relationship between human rights and the phenomenon of natural law, which is revealed when we consider how human rights claims can justify the moral demands made on other agents and on the political community. Without prior moral duties – a natural law – human rights claims are impugned by the ‘individualist fallacy’, whereby the potential value of the right to the claimant is presumed sufficient to impose overriding duties, without due consideration being paid to the constitutive social commitments necessary to make that value a matter of common concern and action. The failure to come to grips with this problem, we argue, has led to certain blindspots in contemporary human rights theory and practice. This chapter draws to a close by identifying the key benefits we see accruing from a natural law theory of human rights.

Does the concept of natural rights have roots, logical and historical, in the concept of natural law? Our answer is, ‘it depends’. By this, we mean that some conceptions across Western history do not in fact allow for the derivation of natural rights in the subjective sense. In contrast, others are conceived such that natural rights follow logically therefrom. Our premise is that talking about ‘natural law’ in the singular – at least in the period from Roman times to sixteenth-century – represents a distortion of on-the-ground realities.

This chapter begins with an etymological and historical elucidation of the terms conscientia and synderesis. Philosophical and theological reflection on these terms, beginning with St. Jerome and proceeding through thinkers such as Peter Lombard and Philip the Chancellor, constitutes the background against which St. Thomas Aquinas develops his understanding, not only of conscientia and synderesis, but also of objective right (ius) or rights. Much of the debate regarding synderesis, the infallible basis of conscientia, concerns whether it is a power or habitus. Aquinas settles on understanding synderesis as a ‘habit’ of the potential intellect – which, following Aristotle, he understands as a sort of ‘blank slate’ upon which things can be written. One of the things written on the habit of synderesis is the practical version of the principle of non-contradiction: ‘good is to be done and pursued, evil avoided’. This allows him to develop a theory according to which objective rights are primary, although not to the exclusion of subjective rights. It also allows those in agreement with Aquinas to exclude subjective rights that contradict established objective rights.

Animals are highly vulnerable in war. However, they are only incidentally protected by international humanitarian law, namely as mere objects (or property), as specially protected objects, as part of the environment, as endangered species, as war weapons, or as means of medical transport, search and rescue. They are neither treated as ‘subjects of protection’ nor are they granted any rights. The research has revealed that the few international humanitarian law provisions that could potentially apply to animals have rarely been enforced or effectively implemented by international courts and tribunals. In light of these general observations, the concluding chapter summarises the key findings of the study. It highlights the main legal challenges that an agenda of protection of animals during warfare faces. It then formulates recommendations for addressing these challenges with a view to strengthening and developing the legal framework.

In De jure belli ac pacis, Grotius constructs international law with the vocabulary of private law. For this purpose, he uses distinctions from the Institutes of Justinian and the Digest, but redefines key concepts of Roman law, such as natural law or law of nations (jus gentium). In doing so, he uses a method that is typical for humanist jurisprudence. On the one hand, he describes history, on the other hand, he renews the traditional system of law and adapts the law to the needs of his own day and age.

What is the legacy of Grotius’ doctrinal efforts, and how did they impact on current structures of international law? Was he providing a natural law foundation for the global order, or rather an instrument of power for sovereigns to assert their political and commercial dominion over the world?

Beginning with their Master General, Cajetan, Spanish Dominicans precipitated and outlined the theological parameters for thinking about infidel dominium of peoples outside Europe as a matter of restitution and salvation. This pairing of justice and evangelization opposed the long-standing idea and practice of missionary war in the theocratic conception of world order that linked conquest and preaching and was being defended by Spanish theocratic royalists and the “modern” theology of John Mair. In 1535, after Francisco Pizarro’s conquest of the Inca, Francisco de Vitoria, Domingo Soto, and Bartolomé de las Casas drew from the inspirational example of the first Dominican missionaries to the New World and began formulating an unprecedented scholastic theological conception of world order. Appealing to Scripture, the apostolic tradition, Thomistic moral theology, Roman law, and canon law, their account of world order contained a discourse of natural subjective rights for all persons made in the divine image, attentive to restoring the injustices suffered by the Amerindians of the New World. The originality of the Spanish Dominicans, with Vitoria’s Relectio de Indis at the center, lay in their articulation of infidel rights over and against unjust European claims of expansionary religious wars waged by emperors and popes alike.

In contrast to current versions of critical theory which in their attack on liberal-capitalist societies develop a more or less vague vision of a socialist society, Christoph Menke, - Frankfurt School third generation - in his brilliant monograph, Kritik der Rechte, Suhrkamp 2015 (A Critique of Rights) fights on two-fronts. He directs his critique not only against liberal-capitalist formations with their conglomerates of societal power, but also against socialist-communist formations with their totalising aggregation tendencies. Against both, he attempts to formulate a theory of the authentic political judgment, which is based upon “counter-rights” in a “new law”.

In the face of obvious deficiencies of both formations, this is a remarkable attempt to develop utopian ideas in politics and law. Building on these ideas, the author suggests is to go beyond individual counter-rights on which Menke focuses exclusively, and to articulate genuinely social counter-rights in three dimensions – in the communicative, the collective and the institutional dimension. What is more, they need to be developed in two directions. One direction is the attribution of counter-rights to collectives, organisations, social movements, networks, functional systems, not as substitutes for individual rights to resistance but as their supplements. The other direction is the pluralisation of counter-rights which Menke defines in a unitary manner. Counter-rights will need to be developed with a high degree of variation if they are supposed to overcome motivation constraints in various media of communication.