Hermotimus, or the Rival Philosophies (70)

Lycinus Why, my friend, even if we find some one who claims to know this art of demonstration, and is willing to impart it, we shall surely not take his word for it straight off; we shall look about for another man to resolve us whether the first is telling the truth. Finding number two, we shall still be uncertain whether our guarantor really knows the difference between a good judge and a bad, and shall need a number three to guarantee number two; for how can we possibly know ourselves how to select the best judge? You see how far this must go; the thing is unending; its nature does not allow us to draw the line and put a stop to it; for you will observe that all the demonstrations that can possibly be thought of are themselves unfounded and open to dispute; most of them struggle to establish their certainty by appealing to facts as questionable as themselves; and the rest produce certain truisms with which they compare, quite illegitimately, the most speculative theories, and then say they have demonstrated the latter: our eyes tell us there are altars to the Gods; therefore there must be Gods; that is the sort of thing.