 Theories of human evolution over the last two million years are severely limited by the very incomplete fossil record and the fact that soft tissue disappears quickly. Given these constraints it is surprising the extent to which cognitive theorising has reached into the very distant past, though its claims are agreed on all hands to be highly provisional. A vital resource has been the study of stone artefacts going back two million years or more, artefacts which preserve very well and which are available in great quantities. We are able to reconstruct a good deal about the methods of their construction and to speculate in a reasonably informed way on the cognitive capacities they require. Based on these speculations innovations in stone tool manufacture have been linked to the development of language (Higuchi et. al. 2009).