But there is a third principle at work which we cannot view with the same favor. As said above, every Muslim must attach himself to a legal school, and may choose any one of these four. But once he has chosen his school he is absolutely bound by the decisions and rules of that school. This is the principle against which the Zahirites protested, but their protest, the only bit of sense they ever showed, was in vain. The result of its working throughout centuries has been that now no one—except from a spirit of historical curiosity—ever dreams of going back from the text-books of the present day to the works of the older masters. Further, such an attempt to get behind the later commentaries would not be permitted. We have comment upon comment upon comment, abstract of this and expansion of that; but each hangs by his predecessor and dares not go another step backward. The great masters of the four schools settled the broad principles; they were authorities of the first degree (_mujtahidun mutlaq_), second to Muhammad in virtue of his inspiration only. Second, came the masters who had authority within the separate schools (_mujtahidun fi-l-madhahib_) to determine the questions that arose there. Third, masters of still lesser rank for minor points (_mujtahidun bil-fatwa_). And so the chain runs on. The possibility of a new legal school arising or of any considerable change among these existing schools is flatly denied. Every legist now has his place and degree of liberty fixed, and he must be content. [Sidenote: THE CANON AND CIVIL CODES]