"The writings of the ancients, the best authors I mean, being full and solid, tempt and carry me which way almost they will: he that I am reading, seems always to have the most force, and I find that every one of them in turn has reason, though they contradict one another. The facility that good wits have of rendering everything they would recommend likely, and that there is nothing so strange to which they will not undertake to give color enough to deceive such a simplicity as mine, this evidently shows the weakness of their testimony. The heavens and the stars have been three thousand years in motion; all the world were of that belief till Cleanthes the Samian, or, according to Theophrastus, Nicetas of Syracuse, bethought him to maintain that it was the earth that moved, turning about its axis by the oblique circle of the zodiac; and in our time Copernicus has so grounded this doctrine, that it very regularly serves to all astrological consequences: what use can we make of this, except that we need not much care which is the true opinion? And who knows but that a third, a thousand years hence, may overthrow the two former?—
“Thus revolving time changes the seasons of things; that which was once in estimation becomes of no reputation at all, while another thing succeeds and bursts forth from contempt, is daily more sought, and, when found, flourishes among mankind with praises and wonderful honor.”
So that when any new doctrine presents itself to us, we have great reason to mistrust it, and to consider that before it was set on foot the contrary had been in vogue; and that as that has been overthrown by this, a third invention in time to come may start up which may knock the second on the head. Before the principles that Aristotle introduced were in reputation, other principles contented human reason, as these satisfy us now. What letters-patent have these, what particular privilege, that the career of our invention must be stopped by them, and that to them should appertain for all time to come the possession of our belief? They are no more exempt from being thrust out of doors than their predecessors were."
Michel de Montaigne, Essays of Montaigne, vol. 5, trans. Charles Cotton, revised by William Carew Hazlett (New York: Edwin C. Hill, 1910). Chapter: ESSAYS OF MONTAIGNE