The ability to come home again was essential if a people were to enrich, embellish, and enlighten themselves from far-off places. In a later age this would be called feedback. It was crucial to the discoverer, and helps explain why going to sea, why the opening of the oceans, would mark a grand epoch for humankind. In one after another human enterprise, the act without the feedback was of little consequence. The capacity to enjoy and profit from feedback was a prime human power. Seafaring ventures, and even their one-way success, were themselves of small consequence and left little record in history. Getting there was not enough. The internourishment of the peoples of the earth required the ability to get back, to return to the voyaging source and transform the stay-at-homes by the commodities and knowledge that the voyagers had found over there. Fourth-century coins made in Carthage have been found in the Azores, and ancient Roman coins seem to have been left in Venezuela by vagrant wind-driven vessels. Vikings from Norway and Iceland appear to have touched North America from time to time in the Middle Ages. In 1291 the Vivaldi brothers from Genoa set out to round Africa by sea, but they disappeared. It is possible, too, that in pre-Columbian times a Chinese or Japanese junk may have been driven off course all the way to the shores of America. But these acts and accidents that produced no feedback spoke only to the wind.

“The Portuguese Discoverers”, from “The Discoverers”, Daniel J. Boorstin, The National Board for the Celebration of Portuguese Discoveries, Lisbon, 1987