The Spanish philosopher and theologian Francisco Suárez (1548-1617) taught an eclectic form of scholasticism and laid the first foundations for a theory of international law.
Francisco Suárez was born in Granada on Jan. 5, 1548, and studied canon law at the University of Salamanca. In 1564 he entered the Society of Jesus; he later taught philosophy and theology in Segovia, Ávila, Valladolid, Rome, Alcalá, Salamanca, and Coimbra. He died in Lisbon on Sept. 25, 1617, after a prolific writing career.
Suárez's two main works are Disputationes metaphysicae (1597) and De legibus (1612). The former is the first scholastic treatise on metaphysics that followed an order of its own rather than Aristotle's exposition. In philosophy Suárez remains primarily loyal to St. Thomas Aquinas, but at the same time he attempts to combine Thomas's ideas with doctrines found in John Duns Scotus and William of Ockham. The distinction between essence and existence, so important in Thomas's metaphysics, is all but abrogated. Suárez's metaphysical theory had an enormous influence during the 17th and 18th centuries, especially in the German Protestant universities, which largely adopted his Disputationes as a textbook.
Equally important and more deserved was Suárez's impact on philosophy of law and on the theory of international relations. In De legibus he proved to be a true and bold innovator who did not always receive the credit to which he was entitled. With his scholastic predecessors, the Spanish philosopher held that all human law participates in the eternal law which governs the entire creation. Yet what constitutes the binding force of civil law is, according to him, not its divine foundation but its human promulgation. Thus all the emphasis comes to be placed upon the positive element of law rather than upon its universal aspect. Although Suárez's philosophy of law is still founded on an ethical basis, it nevertheless provides the distinction needed to give legal theory an independence of its own. The power to legislate resides in the community as a whole, and no individual can claim to have received it directly from God (as King James I had done in his theory of divine right). Nor does the need for legality bind man to any particular form of government, even though Suárez personally considered monarchy the most expedient form.
Suárez had his greatest impact as author of those principles upon which international law came to be based. The notion of a jus gentium, "a law of nations, " was not his invention; it had existed for centuries. But his interpretation is entirely new. Such a law, he claims, is based upon, but is not deducible from, natural law. He considers it to be a law consisting "not in something written, but in customs, not of one or two cities or provinces, but of all or almost all nations."
Further Reading on Francisco Suárez
Studies of Suárez in English are Joseph H. Fichter, Man of Spain: Francis Suárez (1940), and Bernice Hamilton, Political Thought in 16th Century Spain: A Study of the Political Ideas of Vitoria, De Soto, Suárez and Molina (1963). For Suárez's social theories see A. L. Lilley's article, "Francisco Suárez, " in F. J. C. Hearnshaw, ed., Social and Political Ideas of Some Great Thinkers of the XVI and XVII Centuries (1926). Considerable attention is given to Suárez in Frederick Copleston, A History of Philosophy, vol. 3 (1953). Also useful is James Brown Scott, The Catholic Conception of International Law (1934).