While Kant’s account of humankind’s rational progress has been widely discussed, his speculative views about the way in which this progress might have begun and the circumstances surrounding this beginning have been largely neglected. Implicit in such an omission is the assumption that Kant does not say much about the very beginning of human history or that whatever he says is of little philosophical value. This article challenges these assumptions. I reconstruct Kant’s account of the emergence of reason by looking at his various conjectural and more literal remarks about our species’ transition from mere irrational animals into primitive human beings possessing a rudimentary form of rationality. Next, I show how this account fits with Kant’s broader view of humankind’s rational progress and its subsequent stages. By doing so, I elucidate Kant’s guidelines for achieving this progress in the future by unifying them with his regulative view of reason’s past.

A current goal among many scientific disciplines is to incorporate data on past human land use and climate change into current global climate and vegetation models. Here, we used existing archaeological and paleoecological data to provide a spatiotemporal reconstruction of human history in Greater Amazonia over the Holocene. We used an ensemble distribution model based on a database of georeferenced 14C-dated material and environmental factors to predict the changes in spatial distributions of past human occupation sites. We ran these models for the precultivation (13,000–6000 yr ago), early cultivation (6000–2500 yr ago), and late cultivation (2500–500 yr ago) periods. The ensemble models suggest that people mostly inhabited the peripheral areas of Greater Amazonia and the eastern sections of the main Amazon River and its larger tributaries during the precultivation period. Human populations began growing exponentially through the early cultivation period, and people spread and expanded into the interior forests and along river channels in western Amazonia. Populations continued growing through the late cultivation period in these same regions. Our results suggest that many forests, particularly in the peripheral regions and riverine locations, may still be in recovery from disturbances that have occurred repeatedly through the Holocene.