This philosophy, as formulated today, is to a large extent a product of the teachings and philosophy of Rabbi Joseph B. Soloveitchik (1903–1993), Rosh Yeshiva at Yeshiva University. In Rav Soloveitchik's thought, Judaism, which believes that the world is "very good", enjoins man to engage in "tikkun olam". "Halakhic Man" must therefore attempt to bring the sanctity and purity of the transcendent realm into the material world. Centrist Orthodoxy is the dominant mode of Modern Orthodoxy in the United States, while Torah Umadda remains closely associated with Yeshiva University.