José de Acosta, Historia natural y moral de las Indias (Seville, 1590)
The Jesuit book that treated the Americas as a problem in natural philosophy rather than a catalogue of marvels. Printed at Seville in 1590, it argues from the distribution of wild animals that the two land masses must join somewhere unexplored and that people walked over; it gives the first sustained clinical account of altitude sickness, and gets the cause right; and it reads Andean knotted cords as a system of record.
Why this wins its question: Acosta is usually reduced to a single sentence - "a Jesuit anticipated the Bering land bridge" - with no indication of how he got there. The reasoning is what is quoted here from the 1590 sheets: a biogeographical argument that runs from the impossibility of shipping foxes and lions to a conclusion about continental geography, stated in his own words and labelled by him a conjecture. Beside it stand the altitude passage, which is a clinical observation followed by a correct inference about the density of air, and the quipu chapter. The counterweight comes from the same pages rather than from outside: the migration argument is embedded in a ranking of the first arrivals as savages rather than people of polity, and the author is an interested party writing for a royal patron.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The first edition was printed at Seville in the house of Juan de León in 1590, "Con privilegio", dedicated to the Infanta Isabel Clara Eugenia, and its title page states the scope: the notable things of the sky, the elements, metals, plants and animals of the Indies, and the rites, ceremonies, laws, government and wars of the Indians. Natural history and what the author calls moral history are bound in one argument, not two books.
The argument for how the Americas were peopled is biogeographical before it is anything else. Acosta asks how the wild animals got there, and rejects the answers available to him: that God created them a second time in place, that Noah's descendants carried breeding pairs, or that men shipped them for hunting. Who could believe, he asks, that men who navigated with such infinite difficulty took the diligence of carrying foxes to Peru, and above all the kind they call skunks, the filthiest and most stinking creature he has seen - or that they brought lions and tigers?
From that he draws the conclusion the book is remembered for, and states it as a conjecture rather than a finding: "Este discurso que he dicho, es para mi vna gra cojetura, para pensar que el nueuo orbe, que llamamos Indias, no esta del todo diuiso y apartado del otro orbe". His own opinion, he says, held for some time, is that the one land and the other join and continue somewhere, or at least come very near, and that until now there is no certainty to the contrary, because the whole length of the land toward the Arctic Pole is not discovered or known.
He applies the conjecture to people as well as animals. The lineage of men came over passing little by little until it reached the new orb, helped by the continuity or nearness of the lands and at times by some navigation; this, he concludes, was the manner of their coming, and not a fleet fitted out on purpose nor any great shipwreck. He adds that the new orb has not been inhabited by men for many thousands of years. The Bering land bridge was described from evidence in 1590 and confirmed as geography only in the eighteenth century.
The same passage carries a judgement that a celebratory reading would drop. Acosta holds that the first men to enter the Indies were savage men and hunters rather than "gente de Republica, y polida"; that they came through having lost their own land or being pressed to seek a new one; and that they began to settle it with no more law than a little natural light, and that much obscured. The insight into migration is carried inside a hierarchy of peoples.
Book three contains a first-person clinical account of what the Andes do to a body. Crossing Pariacaca, at the highest point of the ascent, Acosta was seized almost suddenly with so mortal a distress that he thought of throwing himself from his mount to the ground; there followed retching and vomiting so violent that he thought he would give up his soul, bringing up food, phlegm, choler, then a yellow and a green humour, and at last blood. It lasted only three or four hours, until they came well down; of some fourteen or fifteen companions all were badly fatigued, some asked to confess believing they would truly die, and one lay on the ground crying out from the pain.
He then reasons to the cause, and reasons correctly. The trouble is the air of that place; the whole remedy, and he says it is a great one, is to stop the ears, nose and mouth as far as one can and wrap the body, above all the stomach. That place, he writes, is one of the highest parts of the earth in the world, so that the snowy peaks of Spain, the Pyrenees and the Alps of Italy seem ordinary houses beside high towers; and he is persuaded "que el elemento del ayre esta alli tan subtil y delicado, que no se proporciona a la respiracion humana, que le requiere mas gruesso y mas templado". He notes that the effect is not felt on cold European peaks, that it strikes hardest on those climbing from the coast, that beasts suffer it too, and that it can happen under a bright sun and in warm air - so the agent is not cold.
Book six treats Andean recording as a technique rather than a curiosity. Acosta describes the quipus - knots and colours on cords, drawing from them innumerable significations of things - and states that they were still in administrative use: an Indian arriving to be tried before a corregidor produced his knots as an itemised account of two or three years, of what was given in one town, what was not paid, what was furnished at another house, what fodder for horses, down to the tomines. He records seeing a bundle of threads on which an Indian woman carried the general confession of her whole life, and confessed by them; he questioned her on details, and the threads answered.
He also describes counting boards of pebbles, on which old and infirm men learned the Pater Noster, the Ave Maria and the Creed, and a reckoning of contributions so intricate that a good accountant with pen and ink could hardly manage what the Indians did with grains of maize. Set against claim c5, the book contains both positions: the first arrivals ranked below people of polity, and the peoples he actually observed credited with instruments of record he could not match.
Acosta is not a disinterested witness and the tier reflects it. He wrote as a Jesuit who had been provincial in Peru and who directed the texts of the Third Council of Lima; the book is dedicated to a royal patron, and the questions it settles are ones the Spanish presence in the Indies made urgent. Much of the Peruvian material is reported from informants he names only in passing, as with the strait he discusses on the word of a pilot examined by the viceroy Martín Enríquez.