Which Islamic scholar's 14th-century Muqaddimah founded the study of social cohesion?

Ibn Khaldun, whose introduction to a history of the Arabs and Berbers turned into a book about how societies work at all - written in about five months while he was holed up in a fortress in Algeria, avoiding the politics that had already had him imprisoned by one ruler and employed by several others.

His engine is asabiyyah, group feeling: the solidarity that lets a group act as one. Hard conditions on the desert margin produce it strongly, which lets a tribal coalition take a city; settled prosperity then dissolves it over three or four generations, until the dynasty is soft enough for the next group to arrive. He treats this as a cycle with a rough period, and derives it from evidence rather than from theology.

He also insisted that historians must test their sources against what is possible - that a chronicle reporting an army of 600,000 should be checked against how many men that country could feed - which is the argument for source criticism, some four centuries before Europe made it. He met Tamerlane outside besieged Damascus, talked with him for weeks, and left a description of him. Arnold Toynbee called the Muqaddimah the greatest work of its kind ever created.