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6 The Symbolic Inheritance Systems When an evolutionary biologist looks at her own species, Homo sapiens sapiens , she sees a contradiction. On the one hand she recognizes that in their anatomy, physiology, and behavior humans are very similar to other primates , especially chimpanzees. She can see how alike humans and chimps are in the way they express basic emotions, in their highly developed sociality , in their ability to improvise, and in some of their ways of learning. It is easy for her to see why Jared Diamond called our species “the third chimpanzee ” because as an evolutionary biologist she discerns the homologies that suggest a common ancestry.1 Yet, on the other hand, she also sees that humans are very different from other primates: this species of chimpanzee writes music and does mathematics, sends missiles into space, builds cathedrals , writes books of poetry and of law, alters at will the genetic nature of its own and other species, and exhibits an unprecedented level of creativity and destruction, rewriting the past and molding the future. In these respects, Homo sapiens sapiens is totally unlike any other species. What is it that makes the human species so different and so special? What is it that makes it human? These questions have been answered in many ways, but in our opinion the key to human uniqueness (or at least an important aspect of it) lies in the way we can organize, transfer, and acquire information. It is our ability to think and communicate through words and other types of symbols that makes us so different. This view is not new or original, of course. The idea was explored more than half a century ago by the German philosopher Ernst Cassirer,2 and recently it has been discussed in depth by the neurobiologist Terrence Deacon. Like Cassirer, we choose the use of symbols as a diagnostic trait of human beings, because rationality , linguistic ability, artistic ability, and religiosity are all facets of symbolic thought and communication. This is what Cassirer wrote: 190 Chapter 6 . . . this world [the human world] forms no exception to those biological rules which govern the life of all the other organisms. Yet in the human world we find a new characteristic which appears to be the distinctive mark of human life. The functional circle of man is not only quantitatively enlarged; it has also undergone a qualitative change. Man has, as it were, discovered a new method of adapting himself to his environment. Between the receptor system and the effector system, which are to be found in all animal species, we find in man a third link which we may describe as the symbolic system. This new acquisition transforms the whole of human life. As compared with the other animals man lives not merely in a broader reality; he lives, so to speak, in a new dimension of reality. (Cassirer, 1944, p. 24; Cassirer’s italics) Cassirer goes on to suggest that rather than defining man as the “rational animal,” we should define him as the “symbolic animal,” because it was the symbolic system that opened the way to mankind’s unique civilization. The symbolic system—the peculiar, human-specific way of thinking and communicating—may have exactly the same basic neural underpinnings as information transmission in other animals, but the nature of the communication (with self and with others) is not the same. There are special features that make symbolic communication different from information transmission through the alarm calls of monkeys, or through the songs of birds and whales. What symbols are, how they form and develop, and how they are used are among the most complex issues in the study of man, but for us there are some minor consolations. The most obvious is that there is no need to resort to thought experiments to convince anyone that symbolically represented information is passed on from one generation to the next. It is something we all take for granted. Those of us living in the Western world know that most of the people we meet will have at least a nodding acquaintance with the Bible, and will share the long cultural heritage of which it is part. And everyone will readily agree that our symbol-based culture is changing through time: we only have to think of what has happened to technology during the last hundred years to be convinced. However, before we look at cultural change in our species, we will try to explain in general terms what...

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