The problem of differentiating the notions “Topic - Comment” and “Theme - Rheme” still exists in present days' linguistics, and mostly is caused by superficial (mis)understanding about the nature of isolating/Topic-prominent languages. It is noted that such a language is Chinese, on the material of which it is possible to identify both the syntactic (“primary”) nature of the Topic and Comment, as well as the universal one. To solve the stated problem, a spectrum of etymological and ontological differences is also presented. The study was carried out in line with the predicatocentric concept, which considers language as a set of predication chains, based on the continuous transformation of binary topic - comment structures. The article is intended to contribute to the development of the “topic-oriented” linguistics in terms of the ontological consideration of language as an object of linguistics and philosophy.