Søren Aabye Kierkegaard was born on May 5, 1813 in Copenhagen. His father raised him strictly religious. Kierkegaard begins to study theology, but only takes it seriously after his father's death in 1838. In his main work Entweder - oder (1843) there are already two of the three stages of existence that run through his entire work - the aesthetic and the ethical stage. He worked out the religious in later writings. In the aesthetic stage man lives for the direct gain of pleasure. In the ethical, man is able to free himself from his navel-gazing by recognizing that he must also take responsibility for others. He experiences freedom precisely through making ethical decisions. But the transcendent part of his being remains hidden from him, since he cannot fathom the reason for this freedom. It is only when he puts himself in relation to the absolutely unknown, to God, that the ascent to the religious stage becomes possible.
Faith is the epitome of an existential decision whose conditions and consequences he cannot overlook. The transition to the third stage is a "leap" into faith and thus into a completely different relationship to being and to oneself: Man accepts his being set by God. Kierkegaard died on November 11, 1855 at the age of 42. Throughout his life he accused the Danish state church of perverting the original meaning of Christianity. He also vehemently fought against abstract philosophy, especially that of Hegel, and developed a philosophy of concrete existence: Man is in a vague search for himself and thus that being who can and must acquire his own uniqueness. Kierkegaard is considered a pioneer of existentialism.