This chapter focusses on Aquinas’s philosophical arguments for the existence of God. It begins by noting where he offers such arguments. Then it notes his general strategy in presenting them. Unlike many philosophers, Aquinas argues that the claim that we can only know that God exists by means of demonstrative arguments from certain facts about the universe to the conclusion that God must exist as cause of these facts. This chapter explains what that view amounts to for Aquinas and compares and contrasts it with other philosophical approaches to the question ‘How can we know that God exists’. The chapter then turns in detail to Aquinas’s arguments for God’s existence in his De Ente et Essentia (4) and his Summa Theologiae, 1a, 2, 3. The chapter explains how these arguments run and comments on what can be said for and against them.

This chapter provides an account of Aquinas’s life and works. It then explains his intellectual perspectives as an author while noting how he distinguishes between faith and reason. It notes what he means by ‘divine revelation’ and why he thinks that to be important. It also explains what he has to say about ‘sacra doctrina, ‘articles of faith’, and ‘preambles of faith. The chapter then explains why Aquinas can be thought to be an advocate of ‘natural theology’ and why he takes it to be important. Finally, it provides an introduction to some key terms which recur in his philosophy of God, including ‘ens’, ‘ens per se’, ‘ens per accidens ‘form’, ‘substantial form’, ‘accidental form’, ‘matter’, ‘substance’, ‘accident’, ‘cause’, ‘efficient cause’, ‘final cause’, ‘formal cause’, ‘material cause’, ‘effect’, ‘essence’, ‘nature’, ‘substantial change’, ‘accidental change’, ‘sensation’, ‘individuation’, and ‘being’ (esse).

Multiverse hypotheses are often accused of falling so far outside the bounds of “science” that they collide with “religion.” In response to such critiques, proponents will insist that the scientific method necessarily involves extrapolation and speculation, and that the multiverse is merely the most recent in a long line of revolutionary discoveries stretching from Copernicus to Darwin to Einstein and Bohr. This chapter parses two major arguments in favor of multiple (or “parallel”) universes, suggesting that one maintains the multiverse as a scientific hypothesis under active investigation, whereas the other amounts to outdated philosophical theology.

This chapter examines Sadr’s Falsafatuna and Iqtisaduna as seminal Islamic responses to the ideological and philosophical upheavals of mid-twentieth-century Iraq. Against the backdrop of the radical political transformations that culminated in the 1958 July Revolution and the subsequent contest over Iraq’s national identity – between Pan-Arab and territorial nationalists, communists, and Islamists – Sadr sought to articulate a civilizational project rooted in Islamic metaphysics, social ethics, and epistemology. Through a rigorous critique of Marxist materialism, Western empiricism, and behavioral psychology, he constructs a modern Islamic philosophy grounded in rationalist epistemology and natural theology. Engaging with Sunni revivalist thought, Arab existentialism, and emerging discourses in psychology and economics, Sadr formulated elements of an Islamic moral economy and philosophical paradigm that confronted the ideological pluralism of his time. His work repositions metaphysics within the intellectual struggle for decolonization and articulates a modern Islamic worldview aimed at promoting theism, spiritual renewal, and social justice.

This chapter accounts for Emerson’s complex, and sometimes seemingly contradictory, relationship to religion and religious experience. While Emerson definitively left the Christian ministry in the early 1830s – turning his back on eight generations of his forefathers who had all become ministers – he never abandoned a profound interest in broader forms of spirituality, including those outside the pale of Christendom. If reason and faith were to be found “in the woods” (and not the church), as his inaugural debut Nature (1836) provocatively claimed, some critics have read Emerson as a secularist (or at the very least a naturalist), epitomizing larger dynamics of nineteenth-century dis- and re-enchantment. This chapter aims for a more nuanced (and multi-hued) view, arguing that Emerson believed the “spiritual laws” of the cosmos could be explained by the twinned activities of science and poetics as forms of social praxis, a communal making of beauty and truth.

In the West, liberty and equality emerged as individual rights from theological speculations about the nature of God and human beings, and the relationship of human beings to each other and to God. It was a natural theology in which God is beneficent and glorifies in what God has created, having made a world in which it is possible for human beings to pursue happiness. Derived primarily from the writings of John Locke, that natural theology was embraced and expanded upon by Thomas Jefferson and articulated in the Declaration of Independence. The Declaration’s natural theology foundation holds that liberty serves God’s purpose: preservation of creation and flourishing in the pursuit of happiness. And liberty is equal liberty because, as Locke’s philosophy and Jefferson’s Declaration proclaim, human beings’ equality is more than a right; it is a fact of creation. For Locke and Jefferson, and for the “American mind” of the founding era, the theology underlying the Declaration implies duties to one another. Without such obligations beyond the self, egoism would lead to confusion as everyone would assert their own interests, and God’s purpose would not be realized.

The Disputationes metaphysicae was doubtlessly an epoch-making book. Through the centuries it was read and praised not only by scholastic authors such as Hurtado de Mendoza and Gilson but also by non-scholastic ones such as Schopenhauer and Heidegger. After briefly describing the systematic framework of the work, I examine its character, arguing that not only does Suárez attempt to construct a rigorous Aristotelian science of being, but that there is also a certain dialectical character to the work that might be seen as an attempt to capture “contrary aspects of reality.” This peculiarity may at least in part explain the fact that its impact is far more difficult to assess than it is usually assumed.

Evolutionary ideas were in circulation before Charles Darwin began his work and were widely disseminated, arousing much controversy. In addition to the writings of Erasmus Darwin (Charles’ grandfather), French ideas gained some currency in the English-speaking world, especially the views of J. B. Lamarck. These ideas were taken up by radical thinkers who rejected divine creation, to the horror of conservatives. Early discoveries of fossils played a significant role in arousing public interest in the history of life and were often seen as evidence that life had ascended a scale of development (the chain of being) toward humanity. The first-known dinosaurs were fitted into the chain as gigantic lizards, not as evidence of creatures totally unlike anything now alive. This model was adapted to middle-class values in Robert Chambers’ Vestiges of the Natural History of Creation in 1844, again arousing controversy but gradually gaining some credibility beyond the scientific community.

This chapter explores the implications of the new status of belief by reconsidering traditional arguments for the existence of God. If disbelief in the supernatural was not a live option before the appearance of modern secularity, what was the point of articulating proofs of God’s existence? This chapter shows that the so-called classical proofs performed a very different function to the one that they were later to assume, being more akin to spiritual exercises than logical arguments constructed from neutral premises. Crucially, one of the central ‘proofs’—that based on universal consensus—involved an appeal to the ubiquity and universality of religious belief. The demise of this ‘argument’ in the early modern period signalled a major change in how belief in the supernatural came to be understood, indicating that the burden of proof was shifting from unbelievers to believers. This was accompanied by a new conception of natural theology, understood as an enterprise that could provide support for religious belief on rational grounds alone. The changing status of natural theology and proofs for God’s existence correlated directly with the appearance of a new notion of belief and the requirements for its justification.

The distinction between philosophical theology and philosophy of religion is examined in relation to the role of faith commitments in each, and the notion of doctrinal statements as ‘truth claims’ is examined in terms whether ‘natural theology’ can legitimately be pursued. It is argued that the praeambula fidei version of this pursuit is illegitimate, partly because of the way in which ‘design’ arguments have often been overturned and partly because of the kinds of theological considerations put forward by Thomas Torrance and Alister McGrath. The relevance of Thomas Kuhn’s understanding of the scientific enterprise is also noted, especially in relation to his notion of paradigms.