 The fundamental appeal of Positivism was through its notion of “progress”. Based on Auguste Comte’s work, Positivism allowed anticlerical thinkers to dismiss the “theological” stage as a primitive state in the evolution of humanity, one that would inevitably be superseded by the “metaphysic” and “scientific” stages. The political implications and uses of this evolutionary view were obvious: to advance to the highest level, Chileans needed to leave behind the religious influence of the Catholic Church. As articulated by the leading early proponent of Positivism, José Victorino Lastarria, who abandoned his liberal commitments (for being based on abstract, or “metaphysical”, principles), science could address the problems of Chilean society in the most effective way. Others heeded the call, and concentrated on such important priorities as education. The liberal historian Diego Barros Arana had done much in this regard through reforms of the curriculum at the Instituto Nacional, as did Miguel Luis Amunátegui, who, in his role as Minister of Education, in 1879 formally introduced the teaching of science in public schools. But the most significant positivist figure was Valentín Letelier (1852–1919), whose Filosofía de la educación (1927 [1891]) served as the basis for a profound reorientation of philosophical studies in Chile. In his view, the theological and metaphysical emphases that had dominated Chilean education since independence had done little to unify the country around a core of shared beliefs. In his view, only the certainties of science could do that. The instrument for achieving this higher stage was logic, which he successfully introduced in the educational plan of 1893, at the expense of ethics and theodicy. Consistent with this emphasis, Juan Serapio Lois (1844–1913) published the most complete treatment of logic from a Comtean perspective, the Elementos de filosofía positiva (1906–1908), applying logical analysis to the methodology of a range of sciences.