Earlier and contemporary authors had observed the systematic aspects involved in the use of money for the nation’s trade. Locke’s novelty lies in the fact that he observed those systemic connections solely from the perspective of economic phenomena; and ‘necessities’ and the necessity of money constituted the main tool through which he described the phenomena associated with the emerging monetary economy. Instead of making the classic theological reference to usury, Locke built the theoretical foundation and normativity of money on the system of trade and its necessities, and hence on the survival of the nation. In this way he was able to gloss over the earlier theological discourse.

Chapter 7 examines Benjamin Worsley’s manifesto of natural sciences that contained utopian ideas about human capacity to overcome death, if only the right scientific approach and the right moral attitude could be achieved. Revelation substituted what Boyle believed was the impossibility of grasping moral natural law rationally. Therefore, the study of moral natural laws is practically irrelevant in his work. Boyle moved constantly between a self-sufficient and mechanistic idea of the physical world and recourse to an infinitely wise God as a guide to human knowledge. He wrote several ambitious works on these issues, which are nowadays considered foundational to the Scientific Revolution but remain practically unknown beyond specialist circles nowadays. The chapter looks in particular at The Origine of Formes and Qualities and A Free Enquiry into the Vulgarly Receiv’d Notion of Nature. These works articulate Boyle’s ambition to transmute everything in nature and his momentous critique of nature, a metaphysical and sacred concept that had been part of Western culture since at least the era of the great Greek philosophers.

The natural philosopher Robert Boyle, mentor of John Locke, took the view that the aim of science was ‘the Empire over the Creatures’. The task of Chapter 6 is to show how Robert Boyle’s new political system for an economics of natural science, primarily involving the utilitarian exploitation of nature and of trade, connected with his contribution to the development of a form of natural law and natural philosophy shorn of moral natural law. That idea drew on classical theological teachings on dominion over creatures (as set out in Genesis 1:26) together with the economic goal of making natural sciences productive – also considering the significant expansion that the British Empire was undergoing at that point in time. Theological principles about an omnipotent and bountiful God were crucial to Boyle’s plans for the achievement of broader management of nature, but as a rule he avoided consideration of anthropological theology and moral natural law in his scientific writings. A close reading of Of the Usefulness of Experimentall Natural Philosophy and of the Aretology helps in articulating these ideas.

Chapter 5 considers the theology and moral philosophy of the respected theologian and moral casuist, Robert Sanderson. The divine Sanderson despaired of the unfortunate consequences for practical morality of denying the responsibility and freedom of individuals. In its historical context his doubt amounted to finally rejecting the Calvinist doctrine of predestination. Scholars consider Sanderson’s Several Cases of Conscience Discussed in Ten Lectures in the Divinity School at Oxford a main reference for Locke in the writing of the unpublished Two Tracts of Government and his foundational Essays on the Law of Nature. Sanderson’s work sets out a moral philosophy of free will reinforced by mechanical overtones of necessary causality in reasoning. The chapter briefly analyses this type of ‘mechanical conscience’ and shows how Sanderson was committed to a de facto theory of government.

The goal of the final chapter is to examine the central role of necessities in the epistemological, moral and political theory of An Essay of Human Understanding and of the Two Treatises of Government. A study of the former shows Locke’s preoccupation with classical moral questions such as happiness and the ‘good objects of desires’ and how necessities helped him to strike a balance between tradition and the new science. As a rule of thumb of proper conduct, knowledge of necessities leads to the preservation of life, a human being’s most important duty to God. His doctrine of necessities is what made it possible for Locke to develop the theory of the public good with which, it is argued, he attempted to defeat the egoist theory of self-interest. Examination of his conception of property and money through the lens of human necessities shows a certain ambiguity in Locke’s normative ideals. Nevertheless, my conclusion is that above other considerations underlying the capital-oriented ideals of the period, the last word of Locke’s political theory is the public good represented by preservation and convenience for the commonwealth and, when possible, for the whole of humanity.

The implications for morality and natural law of Hobbes’s skilful employment of Neoplatonist metaphysics such as Avicenna’s, entailing a sharp division between the human soul and the human body, are spelled out in Chapter 3. This shows that the concept of need, rather than right is central to Hobbes’s natural law and political theory. Judgements concerning needs, including the needs of others, represent a constant source of legitimacy for acting in the state of nature and in the commonwealth. A thorough analysis of the doctrine of necessity in Leviathan, Hobbes’s masterpiece, follows. The superior and absolute sovereignty that Leviathan evaluates and proposes is the true and scientific concept of sovereignty in a commonwealth, by reference to the needs of human nature and also in accordance with divine command. Hobbes exploits his doctrine of metaphysics of necessity to explain that that type of absolute sovereignty is compatible with freedom; after all, each free act of every human being is necessary in the sense of a metaphysics of necessity.

To understand our current world crises, it is essential to study the origins of the systems and institutions we now take for granted. This book takes a novel approach to charting intellectual, scientific and philosophical histories alongside the development of the international legal order by studying the philosophy and theology of the Scientific Revolution and its impact on European natural law, political liberalism and political economy. Starting from analysis of the work of Thomas Hobbes, Robert Boyle and John Locke on natural law, the author incorporates a holistic approach that encompasses global legal matters beyond the foundational matters of treaties and diplomacy. The monograph promotes a sustainable transformation of international law in the context of related philosophy, history and theology. Tackling issues such as nature, money, necessities, human nature, secularism and epistemology, which underlie natural lawyers’ thinking, Associate Professor García-Salmones explains their enduring relevance for international legal studies today.

Chapter 10 analyses Locke’s early writings on money within the wider context of his corpuscularism and explores what I have termed his ‘doctrine of necessities’. The chapter argues that his theory concerning the ‘necessaries’ and ‘necessities’, rather than ‘rights’, gives systematic coherence not only to his political and economics writings but to his entire philosophical theory. In Locke’s early writings on money, the key issue concerns economic phenomena that belong to an interdependent scientific system. The chapter discusses in detail the literature dealing with moneylending that existed before Locke and demonstrates in this manner his originality.

Chapter 4 discusses the circle that formed around the intelligencer Samuel Hartlib (1600–1662). Its overarching argument is that utilitarian science offered guidance in finding the simplicity of the unum necessarium (Luke 10:42), a common theme exalted by contemporary Millenarianism of the Protestant cause. In practical terms, knowledge about necessities became the means to achieving that goal of faith. The scepticism of the period and its obvious corrupting effects on morality and devotion led to inventiveness in pursuit of substitutes for the classical moral principle of the light of reason. The Reformers worked towards a political and theological project of a utilitarian science as a means by which to reach God and reproduce Paradise on earth. Scientific knowledge about trade became central and was expressed, significantly, in the momentous Navigation Acts of 1651.

Chapter 2 analyses Hobbes’s ‘doctrine of necessity’, which was famously so termed by Hobbes himself in his debate with Bishop Bramhall. It argues that by means of this doctrine’s basis in the natural sciences Hobbes transformed natural law from an idealist to a pragmatic enterprise, from one based on natural rights to one characterized by the pragmatic employment of principles of necessity. The chapter discusses Avicenna’s metaphysics of existence, through which he described ‘nature’, which gives precedent to what exists in the material world and depends on the necessitarian principle that ‘whatever exists is necessitated by another’. Similarities between Avicenna’s metaphysics and Hobbes’s are analysed, and in respect of the former the capacity of the doctrine of necessity to sustain a metaphysical framework for philosophy and politics is identified.