The article describes the influence of the philosophical tale genre in the adventure-philosophical fantastic of the 20th century. Main characteristics of philosophical tale is associated with experimental verification of philosophical ideas. The idea is tested in the adventure plot and characters in the discussions, so the important role is played by philosophical dialogue. The adventure plot creates a crucial event which reveals the idea. Characters' philosophical tales and images of internal peace are sketchy and tentative. Philosophical tale is focused on satire and parable, and therefore duality; and metaphorically, it is linked to the “current modernity” and eternal problems. The moral choice is related to traditional patterns. The adventure-philosophical fantastic in the spotlight is a philosophical idea - “what makes human to be human”. The hero is tested in contact with the impersonal and superhuman strength. Tests of the hero and ideas are not separated from each other, and this is significantly influenced by Fyodor Dostoyevsky's novels. Hero selecting is morally ambiguous. The hero faces new subhuman standards. The adventure-philosophical fiction is a new type of hero, being the personification of “human nature” rather than the type or character. Adventure-philosophical fiction should be distinguished from the philosophical satire of “Gothic fiction”.