Travellers who find themselves astray in some forest must not wander now this way now that

My second maxim was to be as firm and resolute in my actions as I could, and to follow no less constantly the most doubtful opinions, once I had determined on them, than I would if they were very assured, imitating in this travellers, who, finding themselves astray in some forest, must not wander, turning now this way now that, and even less stop in one place, but must walk always as straight as they can in a given direction, and not change direction for weak reasons, even though it was perhaps only chance in the first place which made them choose it; for, by this means, if they do not go exactly where they wish to go they will arrive at least somewhere in the end where they will very likely be better off than in the middle of a forest.

René Descartes, Discourse on Method and The Meditations (Penguin Classics, 1968) pp. 46-47