 Lastarria’s most important theoretical work is Lessons in Positivist Politics (Lecciones de política positiva) published in 1875. The influence of positivism is manifest in this work. By contrast with Comte, however, Lastarria was a thorough individualist who extolled the perfection of the individual and the value of individual liberty. He refused to subordinate individual liberty to social order and maintained throughout his political writings that society should protect the full exercise of individual liberty. The central idea that Lastarria took from Comte is the thesis that modern societies need to be guided by experience and scientific observation. According to this, politics must be an experimental science based on experience and observation, which are the only solid basis for social organization. Following Comte, Lastarria maintained that it is possible to comprehend society’s progressive movement by uncovering the laws that govern social phenomena. On his view, in order to examine a particular form of social organization, it is necessary first to determine the laws that govern humanity’s progress. The most fundamental law that Lastarria identifies and that, according to him, impulses humanity forward, is “moral liberty”: the tendency to augment and develop all of our faculties (Lecciones, 3rd Lesson). Social progress, on his view, is a product of this development. This is a perfectionist conception of the human person according to which perfection is not only an individual end but also the most important social end.