information:classification, structural:expansion
Education and study group

Sometime between 1654 and 1657, Spinoza started studying Latin with political radical Franciscus van den Enden, a former Jesuit and atheist, who likely introduced Spinoza to scholastic and modern philosophy, including Descartes, who had a dominant influence on Spinoza's philosophy. While boarding with Van den Enden, Spinoza studied in his school, where he learned the arts and sciences and likely taught others. Many of his friends were either secularized freethinkers or belonged to dissident Christian groups that rejected the authority of established churches and traditional dogmas. Spinoza was acquainted with members of the Collegiants, a group of disaffected Mennonites and other dissenting Reformed sects that shunned official theology and must have played some role in Spinoza's developing views on religion and directed him to Van Enden. Jonathan Israel conjectures that another possible influential figure was atheist translator Jan Hendriksz Glazemaker, a collaborator of Spinoza's friend and publisher Rieuwertsz, who could not have mentored Spinoza but was in a unique position to introduce Spinoza to Cartesian philosophy, mathematics, and lens grinding.

After learning Latin with Van Enden, Spinoza studied at Leiden University around 1658, where he audited classes in Cartesian philosophy. From 1656-61, Spinoza's main discussion partners who formed his circle and played a formative part in Spinoza's life were Van den Enden, Pieter Balling, Jarig Jelles, Lodewijk Meyer, Johannes Bouwmeester and Adriaan Koerbagh. Spinoza's following, or philosophical sect, scrutinized the propositions of the Ethics while it was in draft and Spinoza's second text, Short Treatise on God, Man, and His Well-Being. Though a few prominent people in Amsterdam discussed the teachings of the secretive but marginal group, it was mainly a testing ground for Spinoza's philosophy to extend his challenge to the status quo. Their public reputation in Amsterdam was negative, with Ole Borch disparaging them as "atheists". Throughout his life, Spinoza's general approach was to avoid intellectual battles, clashes, and public controversies, viewing them as a waste of energy that served no real purpose.