The Native Population of Amazonia in 1492 Reconsidered

Denevan rejects his own habitat-density method while retaining the order of magnitude

what the source states

"Consequently I now reject the habitat-density method I used in the past to estimate a Greater Amazonia population in 1492 of from 5.1 to 6.8 million. There was too much variability in densities in each habitat to be able to formulate meaningful average densities on the basis of a few sample densities." And: "I nevertheless still believe that a total of at least 5 to 6 million is reasonable."

what we infer

A number can remain plausible while the argument that generated it fails — the clearest documented example of why this case audits estimate dependencies rather than quoting totals.