He began to study in San Esteban de Ribas do Sil and entered the monastery of Samos in 1690. He took holy orders in 1692. From 1702 to 1707 he taught the new monks. Fray Martín Sarmiento was one of his pupils. He taught Theology at Oviedo University (1709), where he established himself and developed most of his activity. He took a degree and a doctor's degree in Holy Theology at Oviedo University. He was also a teacher within his order and refused several offices such as a bishopric offered by King Felipe V in America.
Many of his speeches and articles were dedicated to medical matters (he practised Medicine with his friends and himself). He also carried out activities related to Law Philosophy. One of his most popular and well-known themes was his opposition to all sort of superstitions, which led to sour polemics. His works were translated into several languages while he was alive. These are some of his most important works: Teatro crítico (1726-90; eight volumes), Cartas Eruditas (1742-60; five volumes), which is an encyclopaedia of the human thought of that time for divulguing his knowledge all over Spain, Ilustración apologéticas, Demostración apologética, Opúsculos, Manuscritos and Poesías.
He was a member of the Philosophical and Medical Society of Seville. He is considered as the forerunner and one of the founders of the modern concept of essay. His work is considered to be utilitarian and pedagogical.