Peter, a celebrated French moralist and theologian, the nephew of Claude Nicole, a French poet, and one of the most illustrious writers of the Port-Royal, was born at Chartres in October 1625. His father, John Nicole, having a perfect knowledge of the ancient languages, instructed him in the elements of grammar, and initiated him so thoroughly in the classics, that at the age of fourteen he had completed his preliminary studies, and read the best works in Greek and in Latin. He then proceeded to Paris, where he commenced a course of philosophy and theology, and at the same time applied to the study of Hebrew; but the weakness of his sight, occasioned by excessive application, obliged him to abandon this pursuit, in which he had already made great progress. Having completed his course of theology, and received the degree of bachelor, he was preparing to take his license, when the troubles which broke out in the university, on the subject of the famous propositions of Jansenius, forced him to defer the accomplishment of this object. Being attached by gratitude and esteem to the inmates of the Port-Royal, he passed several years in that house, occupied in teaching the belles-lettres. But, in 1655, he returned to Paris to labour under the direction of Dr Arnald, with whom he was united by the ties of the most intimate friendship; and, desiring to live altogether unknown amidst the bustle of the capital, he took the name of Rosny. The advancement of Jansenism appears to have furnished the motive that induced him to undertake a journey which he made into Germany, in the course of the year 1658; and whilst there, he not only translated into Latin the Lettres Provinciales, in the composition of which he had participated, but published them, accompanied with very virulent notes. He soon returned, however, to join Arnald; and they retired together to Châtillon, where they applied themselves to the preparation of different writings. Nicole, although he did not entirely adopt the opinions of the Jansenists, made frequent excursions to Port-Royal, Paris, and the neighbouring provinces, in the interest of that party; but in these he acted with extreme circumspection, not choosing, as he himself observed, to play any part in civil wars. Being warmly solicited by his friends to enter into holy orders, he at length resolved to demand ordination of the Bishop of Chartres, in whose diocese he resided. But that prelate refused to ordain him, no doubt by reason of his connections with the Port-Royal. He continued undisturbed at Paris until the year 1677, when a Lettre, which he wrote in the names of the Bishops of St Pois and Arras, on the laxity of the casuists, raised such a storm against him, that he was obliged to withdraw from the capital. For some time he remained concealed in the environs of Chartres and of Beauvais; but the death of the Duchess of Longueville, the most ardent protectress of Jansenism, having decided him to quit France, where he did not consider himself as any longer safe, he left the kingdom, and took refuge successively at Brussels, the Abbey of Orval, and Liège, frequently changing his name and the place of his retreat, and believing himself incessantly exposed to the machinations of his enemies. At length, by the intercession of M. de Harlay, the archbishop of Paris, he obtained permission to return secretly to Chartres, and soon afterwards to fix his residence at Paris, where he resumed his ordinary occupations; and it was then that he completed his Essais de Morale, a work which is less read than esteemed, and which stamped his reputation as a writer. In the last years of his life he mingled in the dispute about Quietism, and took the part of Bossuet against Fénelon, but with wisdom and moderation. Having for some time been deprived of the use of his hands, he was meditating alone in his cabinet when he was suddenly struck with apoplexy. The tidings soon spread in the capital, and the crowd of persons who hurried to visit the pious cenobite proved the high consideration which he enjoyed. Racine, being reconciled to his master, came in a diligence, bringing a medicine (gouttes d'Angleterre) which for a moment revived him; but the resuscitation was soon succeeded by a relapse, and he died two days afterwards, on the 16th of November 1695, at the age of seventy. He had given orders that he should be interred without any ceremony; but his will, in this particular, was not respected, and his remains were accompanied to the grave by the most distinguished men of the time.

Nicole, being of a simple and ingenuous character, evinced during his whole life the timidity of an infant. Nothing was more easy than to embarrass him in discussion; an objection which he had not foreseen entirely disconcerted him. Speaking of Trévillé, one of his friends, he said, "Trévillé beats me in the chamber; but before he reaches the foot of the stair I confute him." In the last year of his life he seldom went abroad, being afraid that, in passing along the streets, a tile would fall upon his head. He had also a great dread of travelling, and particularly of aquatic excursions. During a long period he had relegated himself to the faubourg Saint-Marcel; and when asked the reason of this, he replied, "It is because the enemies who menace Paris will probably enter by the gate of Saint Martin, and consequently will be obliged to traverse the whole city before reaching the place where I live." But, with all this simplicity and timidity, Nicole had a reach and an accuracy of thought which were altogether admirable. He equalled the best dialecticians, in the order, the method, the sequence, and the depth of his ideas; but as his object in all his works was rather to prove than to please, his style, although remarkable for its purity and clearness, often fatigues by its dryness and monotony. "On quitte ses Essais sans peine," says Palissot; "on y revient sans plaisir, parce que les lecteurs ont besoin d'être flattés." Nicole attempted panegyric, but soon found that he had no talent for a species of composition which requires invention and warmth of style.

A list of the works of Nicole will be found in the Mémoires de Niceron (tome xxix.), at the end of his Life by the Abbé Goujet, and also in the Dictionary of Moreri. The following are the principal, viz. 1. Epigrammatum Detectus ex omnibus tum veteribus tum recentioribus Poëtae, cum Dissertazione de vera Pulchritudine, Paris, 1659, in 12mo; 2. La Perpétuité de la Foi de l'Eglise Catholique, touchant l'Eucharistie, Paris, 1664, in 12mo, called la Petite Perpétuité, to distinguish it from the great work which bears the same title; 3. Traité de la Foi Humaine, Paris, 1664, in 4to, a work in which Arnald had some share; 4. Les Imaginaires et les Visionnaires, ou Lettres sur l'Hérésie Imaginaire, Liège, 1667, in two vols. 12mo; 5. La Perpétuité de la Foi de l'Eglise Catholique, touchant l'Eucharistie, Paris, 1669–1676, in three vols. 4to, a masterpiece of reasonings, which appeared under the name of his friend Arnald; 6. Essais de Morale, et Instructions Théologiques, Paris, 1671–1672, in twenty-five vols. 12mo; 7. De l'Unité de l'Eglise, ou Réfutation du Nouveau Système de Jurieu, Paris, 1687, in 12mo. The last writings of Nicole turn upon the system of general grace, which he supported, to the no small displeasure of most of his friends. The consequence was a controversy, which appears to have produced some coldness on both sides. Arnald, in his Letters (tome vii.), expresses himself with much force on the subject; and Quenel complained warmly to Nicole of this species of defection on his part. The various pieces produced in this dispute will be found in a collection of writings on general grace, published by Fouillon in 1715, with a long preface; and a curious analysis of the Traité de la Grace Générale will be found in the Bibliothèque of the Dictionary of Richelet. Nicomedes Nicole had a large share in the Méthodes Grecques et Latines, and also in the excellent treatise on Logic, known under the name of the Port-Royal. The life of this able and laborious writer has been written by the Abbé Goujet, who is, however, more of a panegyrist than a biographer; by Besoigne, in his Histoire de Port-Royal (tome iv.); and also by Saverien, in his Vie des Philosophes Modernes (tome i.).