Life and Mind

plex anatomical features, and differ from modern man principally in their smaller brain capacity. Still more detailed analysis of the recently discovered South African fossils, of early Pleistocene age, convincingly demonstrates that Australopithecus, and numerous other named types whose generic distinctness is questioned, are clearly erect hominids whose brain size in some individuals did not exceed that of the larger great apes. A final brief chapter treats the scanty evidence for the separation of the Hominidae from the Pongidae during the Pliocene or late Miocene. Recent discoveries probably will require revision of some of the points made here. Professor LeGros Clark writes with economy of words and with great precision, yet with a flowing command of the English language rare in a scientist. He has brought the experience of many years of research on living and fossil Primates to bear upon the theme of man's physical evolution, and distilled the essential data and conclusions from a formidable mass of specialized publication. Ware Sinnott, the distinguished geneticist, faces the age-old problem of the relationship between mind and body. After calling attention to the fact that for science the body of man, as well as other living systems, "is a physico-chemical system which manifests the operation of those laws that are found in lifeless systems," he notes that the continued existence of every living organism is dependent upon the precise ordering of all the chemical entities which make up the soma, though these are in constant flux. It is clear, however, that for many people this cannot be the whole answer, for many have an intuitive feeling that there are in man some characteristics which cannot be defined in terms of physico-chemical laws. This is another way of asserting that, although the body is a physical-chemical machine, it possesses other characters loosely called mind, or soul, or spirit which, in some obscure fashion, manipulate the machine. Thus we have on one hand materialism, and on the other, a mixture of the material with the spiritual. The scientist can only work with the basic assumption that there is "uniformity and dependability of natural law everywhere, even in man." In contrast, many men are quite convinced that to be alive is to be free-free to make choices, free to seek goals, to satisfy desires, and to accept or reject moral law. For Professor Sinnott, this second position requires an adequate answer to the question, …