Abstract: This article explores causal relations complicated by modus saturation. As examples, the author selected the modus of necessity with modal predicate must, and modus of assumption with modal work perhaps. The goal of this work consists in examination of causal semantics in modus formations of various type and mark out a demarcation that is important in analyzing causal semantics and logics of similar relations in a sentence and text. The following methods are applies in the course of this research component analysis, propositional analysis, and contextual analysis. The work is conducted within the framework of semantic syntax and logics of language. The main conclusion consists in determination of the primary role of the modus of necessity in the texts with causal semantics, as well as potential of a modus to form the semantics of cause and effect in the texts. The relevance of this article us substantiated by reference to such modern linguistic directions as the logics of language, semantic syntax, and syntax of text.