Samuel Clarke

Life and Intellectual Context

Samuel Clarke (1675–1729) was an English Anglican theologian, philosopher, and one of the most influential interpreters and defenders of Isaac Newton’s natural philosophy. Educated at Gonville and Caius College, Cambridge, Clarke was quickly recognized for his mathematical aptitude and philosophical acuity. Early in his career he produced an influential Latin translation and commentary on Newton’s Opticks (1706), which helped disseminate Newtonian ideas on the Continent.

Clarke was ordained in the Church of England and rose to a series of prestigious posts, eventually becoming Rector of St James’s, Westminster and a royal chaplain. His reputation was established by the Boyle Lectures he delivered in 1704–1705, later published as A Demonstration of the Being and Attributes of God (1705) and A Discourse Concerning the Unchangeable Obligations of Natural Religion (1706). These works sought to show that central theistic and moral claims could be supported through rational demonstration, independent of revelation, even though Clarke remained committed to Christian doctrine.

Clarke’s public profile increased further through his participation in major theological and philosophical controversies. He became associated with a “rational dissenting” strand within Anglicanism that emphasized the use of reason in religion and was suspected by some contemporaries of Arian tendencies for questioning the traditional doctrine of the Trinity in The Scripture-Doctrine of the Trinity (1712). Although formally censured, he retained his ecclesiastical positions.

Clarke’s most famous philosophical exchange is the correspondence with Gottfried Wilhelm Leibniz (1715–1716), conducted through the mediation of Caroline of Ansbach, Princess of Wales. The letters, later published as the Leibniz–Clarke Correspondence, crystallized central disputes in early modern metaphysics and philosophy of religion: the nature of space and time, divine freedom, the problem of evil, and the relationship between God and the created order. Clarke here served as one of the most articulate philosophical spokesmen for a Newtonian theistic worldview.

He died in London in 1729, leaving a body of work that, while less prominent than that of Locke, Leibniz, or Hume in later histories, remained highly influential throughout the eighteenth century, particularly in British philosophy and theology.

Natural Theology and Metaphysics

Clarke’s natural theology aimed to show that the existence and attributes of God could be established by reason alone. In the Demonstration of the Being and Attributes of God, he develops a form of cosmological argument grounded in the notion of necessary existence. Starting from the premise that something now exists, he infers that there must be an eternal and independent being that explains why there is anything at all rather than nothing. This being, he argues, cannot be contingent, since contingent beings require external causes; it must therefore exist necessarily and be the ultimate explanation of all contingent reality.

From this starting point, Clarke proceeds to derive a range of divine attributes—infinity, unity, omnipotence, omniscience, perfect wisdom, and goodness—by arguing that any limitation or composition in the first cause would undermine its status as a necessary being. Proponents of Clarke’s view see this as an ambitious rationalist effort to deduce the traditional attributes of God from abstract metaphysical principles. Critics, both historical and contemporary, have questioned whether Clarke’s move from a necessary being to the specific attributes of the Christian God is logically compelling, and whether his use of the concept of necessity is coherent.

A distinctive aspect of Clarke’s metaphysics is his defense of absolute space and time, closely aligned with Newton’s views. Against Leibniz’s relational theory, according to which space is just the order of co-existing things and time the order of successive events, Clarke holds that space and time are real, infinite frameworks in which things exist and events occur. He treats space, in particular, as in some sense an “immensity” of God’s presence, and time as the measure of the duration of created things under God’s providence.

In the Leibniz–Clarke Correspondence, these issues are tied to broader questions about divine action. Leibniz contends that God, being perfectly wise, creates the best of all possible worlds and has no reason to intervene miraculously or “correct” the system. Clarke replies that such a view diminishes divine freedom and ongoing governance. On Clarke’s account, God can freely choose among many possible worlds and continually sustains and orders creation; he criticizes Leibniz’s principle of sufficient reason when it is taken to uniquely determine a single best world.

This debate leads to the accusation, made by Leibniz, that the Newtonian view (and Clarke’s defense of it) risks portraying God as a kind of watchmaker who must periodically adjust a flawed machine. Clarke responds that regular divine governance and occasional miracles are not signs of defect but expressions of a free and living deity. Later interpreters have treated these exchanges as canonical statements of two contrasting early modern theologies: a dynamic, voluntarist Newtonian theism and a rationalist, optimising Leibnizian theism.

Moral Philosophy and Legacy

Clarke’s moral philosophy, articulated most fully in A Discourse Concerning the Unchangeable Obligations of Natural Religion, offers a rationalist alternative to both voluntarist and subjectivist accounts of ethics. He holds that moral obligations are grounded in the eternal and necessary relations of things, which reason can apprehend as fitting or unfitting, right or wrong. Just as mathematical truths express necessary relations among quantities, moral truths express necessary relations among rational agents, actions, and ends.

On this view, duties such as honoring promises or acting justly are not right merely because God wills them, but are instead eternally and immutably right, and God wills them because they are so. Clarke thus rejects a version of the divine command theory and sides with those who see morality as intrinsically rational. He argues, for example, that gratitude for benefits received or fidelity to contracts follows from the very nature of rational agents and their relations, and that to deny this would be as unreasonable as denying basic logical or mathematical truths.

Supporters of Clarke’s moral rationalism emphasize its attempt to give morality an objective and universal foundation, independent of changing conventions or arbitrary decree. They also note its influence on later thinkers, including the Cambridge Platonists, Ralph Cudworth, and, in a different register, Richard Price and other eighteenth‑century intuitionists, who adopted the language of “eternal and immutable” moral truths.

Critics, however, have raised several objections. Some question whether moral relations can be assimilated to the model of mathematical necessity. Others argue that Clarke provides limited guidance about what to do when alleged necessary relations appear to conflict, or how to adjudicate disagreements about what reason “clearly sees” as fitting. Empiricist philosophers, such as David Hume, later challenged the very idea that reason alone could generate motivationally compelling moral obligations, emphasizing instead the role of sentiment.

Clarke’s broader legacy lies in his role as a central figure in the Newtonianization of early eighteenth‑century British philosophy and theology. His work shaped debates on space and time, divine attributes, and moral objectivity well into the Enlightenment. In France and Germany, where his writings and the Leibniz–Clarke Correspondence were widely read, he contributed to the development of discussions that would later influence Kantian and post‑Kantian philosophy of religion and ethics.

Though later overshadowed in standard philosophical canons, Clarke remains a key representative of early modern rational theism: a project seeking to harmonize the new mathematical physics with a robust doctrine of God and an intellectually grounded moral law. Contemporary scholarship continues to revisit his arguments on necessary existence, absolute space, and rational morality as important documents in the formation of modern metaphysics and moral theory.