'Extrapolation', says the dictionaries, ‘is the method of finding by calculation, based on the known terms of a series, other terms, whether preceding or following.’ The method is proper to mathematics and works efficiently when dealing with number and quantity. When it is transferred to the realm of quality and of organic life, more still to that of history and of culture, it tends to lose its precisely exact scientific quality and becomes a venture in creativity, or, at any rate, a work of fantasy. Imagination now takes the place of calculation. There can be no doubt that the scientist who seeks to learn the origin of man from a fossilized remnant of a skull that might have belonged to a man or to a baboon, must be blessed with a creative imagination as well as with a scientifically exact intelligence. I suppose that when Robert Ardrey, a playwright rather than a professional scientist, sub-titles his book ‘A personal investigation into the animal origins and nature of man’ he is serving notice that he intends to extrapolate with unrestrained imaginative abandon. At any rate, this is what he does !.

There is of course a good basis of scientific evidence in African Genesis. The most recent discoveries of paleontology made in Africa, especially the most notable, those of Dr L. S. B. Leakey at Olduvai in Tanganyika, give very convincing indications that the origin of man was in Africa not in Asia.