Abstract: The goal of this article lies in analysis of the semantics of indefinite pronouns of the English language, which form the core of the semantic field of uncertainty from the perspective of functional linguistics. The subject of this research is the semantic content of English indefinite pronouns in the literary and publicistic texts. The relevance of this work is defined by the lack of works in both domestic and foreign modern linguistics dedicated to indefinite pronouns of the English language. The scientific novelty consists systematization of indefinite pronouns in form of semantic field and determination of possible varieties of uncertainty through the semantics of this group of pronouns in the English literary texts. It is established that in literary texts, the indefinite pronouns of the core of the semantic field of uncertainty of the English language are used for conveying quite very peculiar; however, the key components are uncertainty and generality in evaluation of the unfolding events. Uncertainty can be explicit or conditional. Generality also correlates with uncertainty, leaving out particularities. The absence of particularities is the main semantic indicator of the use of nuclear indefinite pronouns in the literary texts.