Darwin's Dangerous Idea: Evolution and the Meanings of Life. - book reviews

National Review, May 15, 1995 by John Polkinghorne

It seems entirely conceivable that there are holistic laws of nature, currently unknown but in principle scientifically discoverable, which drive the "optimistic arrow" of increasingly fruitful development. Dennett's own mode of exposition provides a way of thinking about how such laws might operate. He likes to talk about evolutionary history as an exploration of Design Space, the vast realm of cosmic possibilities. The way this exploration happens will not be totally random, for there is a metric imposed on Design Space (a pattern of hills and valleys) which tends to direct development in certain directions. The only source of this metric that Dennett will allow is the "fitness landscape," representing differential advantages for survival in the environment. He cannot know that there are not also natural holistic organizing principles at work, driving the increase of complexity and encouraging, say, the development of multicellular organisms despite the manifest survival success of single-cell entities such as bacteria. These principles would impose a further metric on Design Space and might, perhaps, be related to the spontaneous generation of order far from equilibrium. Holistic laws of this kind would be "skyhooks" in Dennett's terminology but they would not be "miraculous . . . unsupported and insupportable."

A skyhook of a more celestial kind would be represented by the purposive will of a divine Creator. This possibility is not to be dismissed by a few (deservedly) snide references to the foolishnesses of "creation science." There is a massive amount of human experience (including that of many of the most remarkable people who have ever lived), and a massive amount of deep human thought (including the reflections of many of the most profound minds that have ever wrestled with such problems), which takes absolutely seriously the existence of a transcendent dimension to reality, capable of lifting us above the level of the world of cranes. One of the successes of twentieth-century theology has been in finding ways of speaking of continuous creation which deliver us from the (theologically unacceptable) picture of an arbitrarily interfering God, replacing it with the concept of a Creator in sustained interaction with creation. All this human search for truth and understanding is apparently dismissed by Dennett as unworthy of consideration. Yet metaphysical myopia does not imply that the more distant view is illusory.

One of the characteristics of Dennett's polemical style is to demand almost deductive certainty of those whose views oppose his own but to allow the mere conjectural establishment of possibility as a defense for the opinions he espouses. We can see this at work in his brief treatment of the Anthropic Principle. This is the remarkable insight that the evolution of carbon-based life in our universe has been possible only because the fundamental physical fabric (as specified by the character and intrinsic strengths of the forces of nature) takes a very precise, "finely tuned" form. In other words, evolution by itself is certainly not enough as the explanation of cosmic fruitfulness. We can readily imagine many universes, close to us in cosmic possibility space, whose histories would be boring and sterile, however long they were left to the interplay of chance and necessity. It is only a very particular universe that is capable of evolving anthropoi. This is an insight that many writers on Darwinian self-sufficiency have chosen to ignore. To his credit, Dennett is prepared to give it a quick glance. Without claiming deductive certainty, many of us have viewed the Anthropic Principle as a significant hint in the direction that there is a purpose at work in cosmic history. We do not claim that it was ordained from all eternity that Homo sapiens should emerge into five-fingered existence (there is certainly historical contingency in a creation "allowed to make itself" through the evolutionary exploration of possibility), but the potential for the appearance of some kind of self-conscious (God- conscious) beings seems to have been built in from the start. What has Dennett to offer as an alternative? No cosmological speculation about evolving, even competing, collections of universes is too wild to be pressed into service. In his view, better a wobbly crane than a stable skyhook.