The present article studies the attitude of the not assimilated Jewish convert, originated and developed in Spain in the 16th and 17th centuries, which has influenced the field of political, educational and spiritual action as well as the academic, literary, philosophical and religious environments in Spain, contributing to the formation of civil society. The thoughts of Francisco Sánchez, also known as the Skeptical (Tuy, 1551 - Toulouse, 1623), will be approached according to the factors that determined the characteristics of the aforementioned attitude along with skeptical elements of his philosophical argumentation..