  Thomas's De modis significandi was the last work to develop Modist doctrine to any significant  degree.[15]  Its clarity and relative brevity led to its adoption as the standard Modist text in medieval universities, replacing the earlier Modi significandi of Martin of Dacia. But by 1330 and for reasons that remain unclear, Modism had completely disappeared from Paris, pushed aside by the more powerful and comprehensive approach of the Summulae de dialectica of John Buridan (ca.  1300–1361).[16]  Modism was never able to overcome certain difficulties, such as its refusal to recognize extra-linguistic context, as a result of which it could not explain how meaning can be communicated via incongruous or imperfect  expressions.[17]  But the most likely reason for its demise was that it no longer provided satisfying explanations of the phenomena it was supposed to explain. The one thing it could do, provide an account of the syntax of Latin grammar, could be achieved more economically by other means. In addition, the theory became absurdly complicated in order to save the phenomena of the modi significandi, suggesting that the modi finally collapsed under their own weight, like so many Ptolemaic epicycles.