The author made an attempt to reveal a number of uncertainties, the presence of which in sociology does not allow to find consensus and generates many alternative criteria for identifying the middle class. In particular, it is shown that, because of the uncertainty in the rethinking by sociologists of the past Soviet era, - the question of the origin of the modern middle class remains open. According to the author, organizational uncertainty leads to ignoring the influence of the specifics of different organizations on stratification processes in the country and makes it difficult to formulate a unified approach to describing the middle class and determining its size. In addition, the author considers the discursive uncertainty and methodological uncertainty of the sociological analysis of the development of the middle class in Ukraine.