The article deals with Lyotard's conception of the differend (a kind of a radical disagreement) and treats it as an attempt to think on/about the Limit: not only about limits between different language games, but also about the Limit as a condition of possibility of philosophy as rational activity, reflecting on which means to find oneself on the limit of thinking itself. This conception presupposes that, firstly, there are untranscendable limits, which separate genres of discourse or phrase regimens; and, secondly, that those limits are recognizable and could be pointed out. To recognize, or to bear witness to the differend, however, means nothing other than to break a limit: to identify the other as such means to draw it into the main discourse, assimilate, and so to destroy the very concept of the ,,dirferend". The article argues that this apparent contradiction must be viewed in the light ofaporetic logic: not as a sign of Lyotard's theoretical weakness, but as an integral part of his conception. Here the ,,limit" is both the condition of possibility and impossibility of the differend.