Among the Jesuits, Vatier seems to have been one of the persons whom Descartes considered to be the most sympathetic to his philosophy. This is the drift of his letter to Vatier of November 17, 1642, where, after having responded to Pierre Bourdin's Seventh Objections, Descartes shares with Vatier the wish that “one should abstain from blaming what one does not understand” (AT III 594–97).

Born in Oreilly-le-Tosson, diocese of Séez, on May 19, 1591, Antoine Vatier joined the Society of Jesus in 1613. Just after Descartes’ departure, he studied philosophy at the Collège Henri IV de La Flèche (1615–18) and kept a position as tutor of grammar from 1618 to 1620, then studied theology in the same place from 1620 to 1624, and was professor of mathematics from 1624 to 1626. Subsequently he was professor of logic, physics, and mathematics in Paris (1626–29), where he had occasion to meet Descartes before the latter's departure to the Netherlands. He returned to La Flèche (1630–32 and either 1634–38 or 1634–42) as professor of theology, with an interlude in Bourges to teach logic and physics (1632–34). In the autumn of 1642, he moved to the college in Orléans, apparently because of the opiniones peregrinae that he seems to have taught his students. In 1650 he translated and edited the Spiritual Exercises of Saint Ignatius of Loyola, a book that enjoyed numerous issues until the end of the seventeenth century. Kept away from teaching, he died in Paris in 1659.

Vatier was among the first to whom Descartes had sent copies of the Discourse. He received them very favorably in two letters that are now lost. Descartes’ replied on February 22, 1638 (AT I 558–65, CSMK 85–88), finding “as much appreciation as anyone could wish for” (AT II 28 and 661), and answers objections that Vatier had doubtlessly raised while admitting to the “obscurity” and poverty of the proofs for the existence of God in Discourse IV (AT I 560, CSMK 85–86).