The author starts with an interpretation of the will in the works of A. Schopenhauer and attempts to deduce the basis of rationality of natural language from the principle of will. It develops the thesis that the basis of natural language rationality lies in the objective-subjective will of language practice, including acquisition, operative and reception practices. He first explains the objective and subjective will, then describes these practices in terms of their objective and subjective will and in the end draws attention to the fact that it is a complex linguistic practice. The author's second thesis is that the will is encoded in the coherence of language practices, which is represented by the relationship between the assimilation base and the reactions realized within language practices. He attributes decisive importance to reception practice, which implies that the existence of property of the sense field “natural language” is a comprehensible existence. This existence is an order of its own that functions as the basis of the rationality of natural language.