Experience teaches effectually, but brutally. It makes us acquainted with all the effects of an action, by causing us to feel them; and we cannot fail to finish by knowing that fire burns, if we have burned ourselves. For this rough teacher, I should like, if possible, to substitute a more gentle one. I mean Foresight. For this purpose I shall examine the consequences of certain economical phenomena, by placing in opposition to each other those which are seen, and those which are not seen.

- Frédéric Bastiat