It should be clear from the foregoing that at present we know a great deal more about Palaeolithic stone implements than we do about the Palaeolithic people who made them. Our data are still too insufficient to warrant any sure account of the way in which the various elements of Palaeolithic culture were developed by different groups of mankind and spread by them throughout the world. However, three fundamental facts relating to this problem may be regarded as reasonably well established:
First, some of the more highly evolved implements and groups of implements found in widely different areas are so similar in shape and technique that we are forced to infer that the cultures in which they occur bear some time-relationship to one another, i.e. the art of making the typical implements in question (such as the handaxe, the Levallois flake and the Aurignacian blade, to name three fundamental examples) was not evolved independently at different times and in different places but was spread from some original center, either by actual migrations of people or by cultural diffusion.
Second, the geographical distribution. of these various type implements, although very wide, is not haphazard, but each one of the fundamental industries has its own distinct area of major development, with outliers along natural routes of migration. For example, the industry characterized by core implements of hand-axe type is found in one continuous area, comprising southwestern Asia, eastern and northern Africa, and southern and western Europe, with outliers in South Africa and India. A less sharply definable industry, characterized by the use of flake implements in preference to cores and (in its most developed form) by the use of flake implements of Levalloisean type with a faceted striking platform, has its home in the same area, with addition of a broad belt stretching through central and eastern Europe and northern Asia. Finally the blade industry has a distribution which is practically identical with that last described, though with a less characteristic development in South Africa and India. The southeastern part of Asia, from the North China plain to Indonesia, seems to form a separate culture province, with an almost entirely independent development throughout Palaeolithic times.
Third, the three major industries just referred to had their principal development at different periods of time, as is shown by the fact that wherever there is stratigraphic evidence they occur in the same order of succession, with the hand-axe industry the earliest, succeeded in turn by the Leval loisean flake industry and that by the blade industry, the latest of all. The foregoing outline is, of course, oversimplified and disregards many problems of local development and relations, but it is based on a mass of evidence, it represents the best opinion of archaeologists today, and it may be accepted provisionally as a true interpretation of the facts.