The article provides a language analysis of the idea of progress. It briefly outlines the method of search for minimal vocabulary as has been proposed by Bertrand Russell in 'Human Knowledge, Its Scope and Limits'. Then it considers the application of this method to a social theory, namely to the language used in a theory of progress. As an example theory it uses the well known essay 'L'anciene regime et la revolution' (1856) by Alexis de Tocqueville. The language of the theory is analyzed, abstracted expressions are pointed out and the minimal vocabulary is presented: it consists of verb-expressions 'to see', 'to be wrong', 'to doubt', 'to think', 'to feel', 'to be surprised', 'to choose', 'to express' and 'to rely'; of noun-expressions 'demise', 'cause', 'change', 'nature' and 'banality' together with pronouns and logical expressions. The rules for construction of composed expressions and propositions are set up and a reconstruction of the object language is suggested. The abstract character of the method is reflected.