For the first time in the history of Russian thought is shown that Fyodor Dostoevsky in the novel “The Brothers Karamazov” has formulated two arguments discussing the dogmas of Christianity: 1) the ontological and 2) the sociological. The ontological argument is expressed in form of the legend of the “badgered boy”. The sociological argument is expressed in form of the legend of the “Grand Inquisitor.” The “Ontological argument” reveals the difficulty of “the ontological nonremovability of sin.” It is also shown that in the basis of legend of the “Grand Inquisitor” is a rigorous logical reasoning – “easy destructive dilemma”. Serial output of this dilemma demonstrates the difficulties connected with an explanation of the nature of “salvation”: will be saved all or righteous only?