The object of this article is the works of German popularizers of science in the 1850s and 1860s of the XIX century-Jacob Moleschott (1822-1893), Karl Focht (1817-1895) and Ludwig Buchner (1824-1899), well-known representatives of the philosophical trend of "vulgar materialism"in Russian historiography. The purpose of the study is to show how scientific research, primarily on human physiology, was used by them to justify their socio — political views, primarily on the place of religion in society and its gradual secularization. The author solves the following tasks: a) critically rethink the content of the category "vulgar materialists" established in Russian historiography; b) determine the specifics of the understanding of "vulgar materialists" of philosophy, theology, religion and science as the main categories of the discourse they use; C) identify the relationship between research in the field of physiology and the socio-political views of "vulgar materialists" in their attitude to the ideas of revolutionary and evolutionary development of society. Although neither "scientific materialism" nor "scientific naturalism" can claim to be a scientific ideology, scientific activity itself can act as a secularizing force when the justifying principles of scientific research and the results obtained with their help are extrapolated to social and political life.