Judging the past by what they know of the present

An Arab Philosophy of History: Selections from the Prolegomena, by Ibn Khaldun and translated by Charles Issawi. 2nd ed. (Princeton), p. 31. A warning from 1400.

Now men are naturally inclined to judge by comparison and by analogy; yet these are methods which easily lead to error. Should they by any chance be accompanied by inattention and hastiness, they can lead the watcher astray, far from the object of his enquiry. Thus many men, reading or hearing the chronicles of the past, and forgetting the great changes, nay revolutions, in conditions and institutions that have taken place since those times, draw analogies between the events of the past and those that take place around them, judging the past by what they know of the present.