Rationalism is an idealistic philosophical direction that considers reason as the only source of knowledge, in which reason is the basis of human knowledge and activity. Because the rational criterion of truth is accepted by many thinkers, rationalism is not a feature of any particular philosophy; moreover, there are different opinions about the role of reason in cognition, from the moderate, where reason is recognized as the main means of perceiving reality, to the radical, where rationality is considered the only main criterion. In modern philosophy, the ideas of rationalism were developed, for example, by Leo Strauss, who proposed to use the method of rational thinking not by itself, but in combination with the acquisition of knowledge with the help of leading questions (mayvetics). Other exponents of philosophical rationalism include Benedict Spinoza, Gottfried Leibniz, René Descartes, Georg Hegel, and others. Rationalism is usually contrasted with irrationalism and sensationalism. In this thesis analyzed some ideas about it.