ABSTRACT
Doubts have been expressed as to whether cannibalism still exists anywhere in the world, and even if it ever existed. Of course, it is difficult to observe something directly if it no longer exists. Using a similar logic doubt has been expressed as to whether the holocaust took place, because there is a paucity of eyewitness accounts of people being gassed. If the only acceptable evidence regarding natural occurrences is direct observation, we would have little to study in the realms of evolutionary biology or archaeology, and would have to abandon historical disciplines that rely on amassing circumstantial evidence to speak to an issue. Care must be taken if reconstructions of the past are used to develop theories, particularly regarding the processes at work, but it is necessary to make the attempt in order to understand the course of events that have shaped us. I have emphasized throughout this book, as well as in my other three books discussing the processes and outcomes of human evolution, that it is necessary to construct conceptual models, and then to evaluate those models using multiple sources of evidence. These different lines of evidence provide the convergence required to evaluate and refine models in order to arrive at more convincing explanations and to make better predictions.
