Jared Diamond's worldview is common currency today. Even the French, who snobbed Guns Germs and Steel when it was published, are now making Collapse a huge success ; I hear from a friend that it is being sold by the tens in a remote country supermarket. Two months ago, Electricité de France launched a huge, desperate-to-look-green advertisement campaign featuring Diamond's version of the downfall of Easter Island (see videoclip here). It is comforting to see one of the greatest naturalist writers of our time becoming mainstream ; Diamond combines geography and the social sciences with a mastery never heard of since Montesquieu. As a storyteller he is enthralling; as a polemist he is efficient and fair ; as a scientist, he is daring. Yet he can be wrong. Two major episodes of the Jared Diamond World History, namely the demise of american empires and the fate of Easter Island, have been revised recently.

* Poor Guns and native Germs

According to Diamond, what caused the collapse of the Inca and Aztecs Empire was, first, germs brought by the conquistadores to which the native's immune system was unprepared (DIamond is merely restating a theory put forward by historians of epidemics such as William H. McNeill or Alfred W. Crosby), and second, western superiority in terms of weaponry.

The idea that western smallpox killed off the native americans seems accepted since the sixteenth century. But identifying an epidemic by means of historical records is an awfully difficult task - see Mc Neill's Plagues and Peoples for a reminder). It is all too easy for a european chronicler to use a european label for an exotic plague, and to dismiss what might be an unknown plague in favour of some good old medical model.

Epidemiologist and physician Rodolfo Acuna-Soto (see here) has examined the 50 volumes of data gathered by the surgeon general of New Spain, and confronted it with ancient Aztec codices; there he discovered that european smallpox (zahuatl), which was known to the Aztecs before the arrival of Cortes, accounted for two important epidemics in 1520 and 1531. But the really dreadful plague of 1545 and 1576, the one that really finished the Aztecs off, was cocolitzi, a hemorragic fever unknown to european medicine. Hemorragic fevers do not transmit from human individual to human individual, so it is unlikely that Europeans would have brought it along or that they carried it back home. Acuna-Soto teamed with historians, archeologists and dendrochronologists to show that the outbursts of cocolitzi were correlated with precise climatic patterns (long droughts followed by sudden rainfall).

As for Guns and Steel, Diamond's technological determinism has often been criticized as ethnocentric and naive. It can be argued (see here) that native americans had better coastal ships, better agriculture, and, yes, a fine tradition of metalworking. In terms of Guns, the 30 muskets Cortes brought with him were very noisy and smoky and frightening, but not to the point that they could overthrow an empire. Efficiency of firearms in this time was limited by rates of firing, bullet spin, external combustion, and recoil. American long bow technology was at its climax; their bows could pierce through a steel armor. Muskets could not. Pizarro's soldiers threw their heavy steel contraptions away to adopt the tightly woven and arrow-proof Inca battledress. Pizarro himself recognized that epidemics, not technology, had won the war.

* Easter Island revisited

Everyone knows Diamond's theory about Easter Island: they comitted ecological suicide by depleting their natural resources and cutting down their forests. Anthropologists Benny Peiser and Terry Hunt challenge this view, each in his own way. Peiser's publishers are said to be funded by puppets of oil lobbies and pharmaceutical industries, and there is an ideological agenda behind his debunking of ''Collapse" (see what the Savage Minds people say about it)). Yet, that does not keep one from being right once in a while. Peiser's point is that european genocide was the main cause of the island's collapse ; he argues that

  • the Little Ice Age and many other factors can be blamed for deforestation
  • Pollinology dates massive deforestation in Rapa Nui to the late XIVth century. C 14 datation tell us that the first settlers came to the island in the XIIIth century. one century seems a short time to deplete the island's resources and build the Moai.
  • Easter, as discovered by the first Europeans (1722), was a rich and prosperous land. 50 years later, things had worsened dramatically. European epidemics may have caused the following decline of the islanders.
  • There is no archeological evidence of war or cannibalism following a societal collapse
  • Fish was always plentiful ; the natives need not have resorted to cannibalism to escape starvation, as Diamond claims
  • The tale of the Moai having been built by a superior civilization that disappeared long ago was taught to the inhabitants by the Jesuits. Westerners wrote this myth, which the natives later repeated, to avoid recognizing architectural genius to what they considered to be an inferior people.

Rats, not humans, might be held guilty for deforesting Easter's palm-trees, says Terry Hunt (see here and here). Hunt cites the Hawaiian case in support of his story, and the fossil records, which indicates a peak in the rat population, followed by a collapse, a pattern coherent with the deforestation data.