Differences between some sentences in the original German text of 1981 and their English translation of 1984 were found in Volume 1 of Habermas's opus magnum. It turned out to be an accurate self-correction of Habermas, which created there a concise summary of the teleological aspects of his speech act theory. This improved the linguistic devotion of his argument, but weakened the practical, social influence of his theory of communicative action. Some other topics within the vast secondary literature on Habermas are also touched: the meanings of the key term 'Verstandigung' ('Understanding'), problems around the validity claims, the formal, procedural character of his theory, i.e. the lack of substantive, causal factors. The latter traits and - behind them - Habermas's close connection with the dominant philosophical trend of the 'linguistic turn' (Rorty 1967) are supposed to have led to the fact that Habermas's theory has failed to fulfil possible hopes about social mobilization effects in the late 20th century. Yet, Habermas's theory has vast significance. Besides complementing the 'paradigm of production' with the one of communicative interaction, enriching the notion of modem democracy, highlighting the significance of interpersonal social networks through the elaboration of the 'lifeworld' concept, Habermas's work in providing theoretical foundations to the problem of modernity is of key importance. Through analysing 'the unfinished project of modernity, of the Enlightenment', whose contemporary defects 'can only be made good by further enlightenment', Habermas sums up the essence of our age of globalization, of capitalism. He provides a program for all social scientific workshops still following the paradigm of historical progress and working for a developed, humane and democratic society, but sometimes being on the defensive today. The extension and supplementation of Habermas's theory of modernity, with a 'social turn' (Roderick 1986) and a 'causal turn' are being proposed.