Official literature is full of poetic claims in different themes (eulogy, love, mysticism, libel, facetiousness, epic, exposition, glory, complaint and etc.). Although it seems that poetry and literature are not in need of analogy and affidavit and other ways of logical reasoning to prove the exaggerated literary claims, in fact the poets and a literary person usually benefit from methods similar to logical reasoning (claim, evidence, reasoning) like simile, allusion, and allegory (proverb, story and fable), proverbial method, discursive practices, and oath in order to express what they have in mind and to objectify the abstract concepts. Meanwhile, paying attention to “Folklore” plays an important role in strengthening and explaining the poet’s mental and intellectual principles in literary expression, and it acts like supporting evidence and the background for proving the claim in literary causal methods. This article analyzes the important role of folk literature and culture in consolidation of semantic and rational foundations of official literature.