The article deals with the comprehension of the concept of reality in the cultural and scientifi c heritage of the French enlightener Denis Diderot. The interest to this topic is dictated by the timeless relevance of the innovative dramaturgical theory of the thinker, in which the issue of depicting the real is central. In the course of the analysis the works of domestic and foreign philosophers and literary critics, who touched upon the problem of the representation of reality in the 18th century and especially in the works of Denis Diderot, were involved. The concept of reality is considered both in aesthetic-philosophical (the article “Beaux”, “Entretiens sur Le Fils naturel”, “Discours sur la poésie dramatique”) and natural-scientifi c (“Pensées sur l’interprétation de la nature” and the article “Nature”) works, which allowed to reveal Diderot’s unifi ed ap proach in defi ning the real and formulating the rules of its representation. The article analyses the approaches to the representation of the real in a work of fi ction, which are described in detail by the enlightener in his treatises on dramaturgy. The study compares the concepts of “nature” and “reality” and explains their diff erences. Nature in Diderot’s understanding is the visible world, objective reality, whereas reality appears as a fi ctional unity, subjectively embodied in an artistic work on the basis of images from memory and imagination. This reality is constructed by the author of the work and is plausible. The author of the article, based on Diderot’s treatises on theatre, has formulated a number of criteria that must be followed in order to recreate a plausible reality. These criteria indicate the same requirements for the arts, which, according to Diderot, are most suitable for depicting the real – theatre, painting and music. The analysis shows that Diderot’s innovative aesthetic system clears the way for the saturation of art with plausible fi ction, and this “enrichment”, in turn, proclaims a new era – the “critical era of theatre”.