Rationality is one of the individual’s most important intellectual qualities. Grounded in critical thinking, it is expressed in the ability to understand reality, align one’s convictions with it, and make well-grounded decisions. Here, reality means everything that exists independently of our desires and convictions, including the objective world, the human being, and society. Rationality helps form a holistic and productive worldview, build one’s life in accordance with reality, and attain a complete and flourishing life.