Arnauld, ANTOINE, known as 'the great Arnauld,' the twentieth and youngest son of the preceding, was born at Paris, February 6, 1612. Entering the Sorbonne, he was initiated into the scholastic theology, and soon conceived a life-long admiration for St Augustine. In 1641 he attained the dignity of doctor, and was ordained a priest. In 1643 he published a work, De la Fréquente Communion, directed against the Jesuit view that the mere reception of the sacrament sufficed, without repentance and preparation, and continued the contest with his Théologie Morale des Jésuites.
Arnauld now buried himself in seclusion for twenty-one years, but his pen was almost continuously active. In 1640 had appeared a posthumous work of Jansenius, Bishop of Ypres, entitled Augustinus, which laid down with a rigour equal to Calvin's the doctrines of predestination, the corruption of human nature, and the depravity of the will. It was specially addressed against the Jesuits, many of whom entertained Pelagian views of the freedom of the human will. The work was condemned by Pope Urban VIII. in 1641. Arnauld ventured to defend it against the papal bull, publishing a first and second Apologie de Jansénius. He also wrote a number of religious works of a non-polemical kind, and became the religious director of the nuns of Port-Royal des Champs, the famous convent of which his sister was abbess. In his retreat he was surrounded by a society of scholarly friends, 'the recluses of Port-Royal,' who lived near the convent—Pascal, Nicole, and others only less distinguished. Here they wrote numerous excellent works—Arnauld and Nicole conjointly the Port-Royal treatises on grammar, geometry, and logic, the last of which, L'Art de Penser, became a standard work both in France and elsewhere. In 1650 appeared what he conceived to be his best work, L'Apologie pour les Saints Pères. In 1655–56, for prudential reasons, he left his retreat at Port-Royal; about the same time he was expelled from the Sorbonne and the faculty of theology.
In 1656 the war with the Jesuits was renewed by the great Pascal in the Provincial Letters—substantially a brilliant defence of Arnauld's position. In 1669 appeared the first volume of Arnauld's Morale Pratique, against the moral teaching of the Jesuits. Arnauld, who was a sincere Catholic, defended the doctrine of transubstantiation in his Grande Perpetuité de la Foi (1669–74); and he wrote two works to prove that Calvinism subverted morality and the teaching of Christ. After the 'peace of Clement IX.' (1668), Arnauld was presented to the papal nuncio and to the Grand Monarque; but under Jesuit influence, the king issued an order for his arrest. Arnauld hid himself for some time, but finally withdrew into Belgium (1679). Though praised for equanimity and gentleness, he was incessantly engaged in keen controversy, even with his friends; for he wrote not against his enemies only, but against Pascal, Domat, Nicole, his protector Pope Innocent XI., Descartes, and his old friend, Père Malebranche. He died at Brussels, 8th August 1694, and was buried in secret. Arnauld is eminent not merely as a theologian and thinker, but as a writer of French. His style is clear and pure; and his works are amongst the first in which the scholastic and cumbrous methods of disputation are superseded by modern French precision and force. As a philosopher, he was one of the first to write against the doctrine of perception by ideas representative of the objects, and in some points anticipates Reid and the Scottish school. His indefatigable energy is well illustrated by the famous reply he made to Nicole, who counselled him to take rest: 'Rest!' answered Arnauld, 'shall we not have all eternity to rest in?' His works, in 45 volumes, were published at Paris (1775–83). See PORT-ROYAL DES CHAMPS, PASCAL.