How archaeologists must sometimes long to be asked to find a needle in a haystack. Such a task is simple compared with the grind of completing jigsaws within jigsaws, in which the pieces of one puzzle cannot even be identified without solving another. Given the difficulties of reconstructing something as relatively simple as a 3,000-year-old vase, can an archaeologist reconstruct a 30,000-year-old mind? Steven Mithen does not merely claim that this is possible. He does it.
In fact he goes even further back. In the course of explaining what produced the first stabs at art and religion, roughly 30 millennia ago, he treks backwards past the emergence of homo sapiens sapiens about 100,000 years ago, to the use of the first stone tools 2.5m years before, past the time of the last known ancestor shared by man and the non-human apes 6m years ago, all the way to the first blobs of evolving life. The point of this journey, however, lies in the present. The moral of Mithen's tale is that "if you wish to know about the mind, do not ask only psychologists and philosophers: make sure you also ask an archaeologist." He exploits the ideas of psychologists (Howard Gardner), philosophers (Jerry Fodor) and theories from other disciplines to construct hypotheses about the mind that can be put to the archaeological test. The results are often more revealing than those obtained by the standard method of examining mentality from the questionable vantage point of the here and now.
Mithen's method is simple. Find out what man made and did, then see what can be inferred about the mental equipment that such achievements would require. A large part of this exercise consists in noticing contrasts between different stages of evolution. The limitations of early man are often as striking as his capabilities. Why did the tool-making Neanderthals never use the eminently suitable materials of bone, antler or ivory? Why did it take early humans 1.5m years to decide to become painters?
The best answers to such questions, Mithen argues, invoke the existence of different types of intelligence. There is general intelligence, social intelligence, natural history intelligence (about animals and plants), technical intelligence (tools) and linguistic intelligence. Sometimes these modules harmoniously interact and sometimes they do not, even when the relevant ones are fairly well developed. Neanderthals failed to carve bone because their technical and natural history intelligences could not cooperate. The Neanderthal engineers knew all about bones as parts of animals; but it was precisely because these objects were associated with animals that they could not also see them as potential tools. A fruitful mixing of separate domains of knowledge is what lies behind such novelties as fashioning animal matter into tools, or mentally combining human-like qualities with the apparent immortality of some inanimate objects to construct the concept of a god.
Mithen's principal metaphor is that of a cathedral in which a central nave of general intelligence is surrounded by chapels devoted to the specialised intelligences. The chapels are at first walled off from the nave and from each other. The turning-points in intellectual progress occur when internal walls get knocked down. The final breakthrough, which created the modern mind, occurred when all parts of the cathedral became interconnected, and complete "cognitive fluidity" was attained. One important step occurred about 100,000 years ago when the social and natural history intelligences became integrated. The final step came 40,000 to 70,000 years later when technical intelligence joined the party.
The mechanism that brought about cognitive fluidity was, primarily, the development of a general purpose language. This more flexible language enabled its possessors to acquire "an increasing awareness about their own knowledge of the non-social world." This consciousness "adopted the role of an integrating mechanism for knowledge that had been 'trapped' in separate specialised intelligences." One particularly liberating component of cognitive fluidity was the use of metaphor and analogy, which "lie at the heart of art, religion and science."
He offers explanations involving natural selection for each chapter in this story: how the chapels were built, why they were initially separated, and how the walls between them came down. Some readers may be disappointed that he devotes only a few pages each to "the search for the origins of art, religion and science" of his subtitle. We find out only the preconditions for these things. Still, to have told such a comprehensive story about what may have led to them is an enormous achievement, and a fine example of "cognitive fluidity."
The prehistory of the mind
Steven Mithen
Thames and Hudson, £18.95
