A suitable project for the new Millenium is to radically reconfigure our image of human rationality. Such a project is already underway, within the Cognitive Sciences, under the umbrellas of work in Situated Cognition, Distributed and De-centralized Cogition, Real-world Robotics and Artificial Life1. Such approaches, however, are often criticized for giving certain aspects of rationality too wide a berth. They focus their attention on on such superficially poor cousins as “adaptive behaviour”, “ecologically sound perception-action routines”, “fast and frugal heuristics” and “fast, fluent real-time real-world action control”2. Is this robbery or revelation? Has 'embodied, embedded' cognitive science simply lost sight of the very phenomena it was meant to explain? Or are we finally seeing rationality aright, as fully continous with various forms of simpler, ecologically situated, adaptive response? I distinguish two ways of developing the 'embodied, embedded' approach. The first, which does indeed threaten to lose sight of the key targets, is fully committed to a doctrine of biological cognitive incrementalism according to which full-scale human rationality is reached, rather directly, by some series of tweaks to basic biological modes of adaptive response. The second depicts human capacities for advanced reason as at best the indirect products of such a process. Such capacities, it is argued, depend heavily upon the effects of a special kind of hybridization in which human brains enter into an increasingly potent cascade of genuinely symbiotic relationships with knowledge-rich artifacts and technologies. This latter approach, I finally suggest, does better justice to our peculiar profile, which combines deep biological continuity with an equally deep cognitive discontinuity.