Post-truth is a concept, a category that represents a social phenomenon, which is associated with a cultural and political climate, in which there is less respect for the truth. In the sense of Post, it suggests the idea of a moment, lasting in time, in which the concept of truth becomes unimportant or irrelevant, being replaced with various insecure knowledge or without logical basis and conclusive arguments, called alternative truths, false, or hybrid truths. The article analyzes the causes and essence of this phenomenon, as well as its impact in the field of educational values. Examining various conceptions regarding the post-truth phenomenon, the authors also refer to the aspects related to the logical-linguistic structures. These structures, at the linguistic level, focus on words and grammatical sentences, and at the logical level, on notions, judgments and reasoning, which are constituted as forms of thinking. Thus the thinking is correct according to the logical form and true according to the content, through an adequacy with reality. Post-truth is a deviation from the truth, violating logical principles and laws, in form and content. The causes of these situations are determined by the semantic uncertainties of the language (ambiguity, synonymy, polysemy, etc.), but especially by subjective manipulations in speeches, in the media and on social networks in order to impose the "authenticity" of their opinions. The authors make a number of suggestions that could help to rectify the situation, namely: - To study deeply the phenomenon of post-truth and provide measures, legally regulated, which would counteract its expansion. In the educational sphere. Provide for the development of paradigms and methodologies to change education and orient it not only to performance and success, but also to a humanistic education, based on beauty, truth and faith. - To carry out actions to optimize the phenomenon of excessive technologicalization of education and application of efficient methodologies for the formation of civic values, for keeping in the didactic arsenal the principles of teaching through heuristic dialogue, especially in the field of humanities. - To apply in education the methods of developing critical and self-critical thinking, in the Kantian spirit and not only of modern nihilism.