<p>This paper documents Dostoevsky’s exposure to, and encounter with, deism in Russian and European public discourses and encompasses the discovery of new sources to his novel <i>The Adolescent</i> (<i>Podrostok</i>). On the basis of hitherto unexplored primary source material, a pattern of indeterminacy is uncovered that characterizes Dostoevsky’s belief system, which extends to his literary works, to which the principle of indeterminacy can also be applied. An objective method of hermeneutics is employed to analyse the changing vision of the future of humanity in <i>The Adolescent</i> and some shorter pieces of fiction published in <i>Diary of a Writer</i> in the 1870s, with which the author concludes that deism played a key role in the formation of Dostoevsky’s vision of Europe’s, Russia’s and humanity’s future. Concominantly, it reaffirms Dostoevsky’s interest in historiography reflected in his intention to discern “future results of present events” (Simonova-Khokhriakova <CitationRef CitationID="CR91">1990</CitationRef>, p. 348). The paper contains some commentary on the persistency with which religious belief, limited to Russian Orthodox Christianity is attributed to Dostoevsky, despite alternative evidence, which is often ignored. It is proposed that the lack of determinacy which attaches to the “message” in Dostoevsky’s fictional oeuvre as well as his polemical articles is grounded not only in his desire to avoid censure and be published, but also in his own uncertainty about the possibility of finding “absolute results” in the movement of time; this mirrors the contemporary world of science, just coming into existence during Dostoevsky’s epoch in which old assumptions about eternity, immortality, and the existence of God were being challenged. The paper pays attention to Dostoevsky’s acquaintance with modern scientific thought that is reflected in the deliberations of his fictional characters.</p>