The article is devoted to the study of the human problem in a digital society. It is a question of changing the very nature of man, of transforming man into a transhuman, and later into a Posthuman. The principle of constructivism in this process is of key importance, forming constructivist thinking and worldview in the social sphere, in science and in culture as a whole. Such properties of radical constructivism as revolutionism, operationalism, efficiency, technicism, pragmatism, reductionism, and utilitarianism are highlighted. The article analyzes such manifestations of Posthuman as artificial intelligence, cyborgization, genetic manipulation, transhumanization, dehumanization of a person.