In this book targeted at a general audience, Francisco Ayala brings both his theological and biological expertise to bear on the challenge of contemporary "intelligent design" creationism. Trained in a Catholic seminary in Spain and now a distinguished evolutionary biologist, Ayala sees no conflict between religion and science. Indeed, he argues that evolutionary biology provides an important solution to the theological problem of evil.
The problem of evil is a classic theological conundrum that faces Christians who believe that God is simultaneously all powerful and all good. How could such a deity allow evil to exist in the world? Ayala's solution is "Darwin's gift" of evolutionary biology. Translated into evolutionary terms, the problem of evil becomes the problem of why numerous imperfections could be allowed in a wide range of organisms if in fact they were created by an all powerful and all good deity (p 159). Why would God design human eyes with a blind spot, Ayala asks, and squid eyes without? "Did the Designer have greater love for squids than for humans and, thus, exhibit greater care in designing their eyes than ours?" (p 154). Evolution by natural selection provides the answer for these imperfections. Evolution is a tinkerer, working with what is available to make what it can, imperfections and all. To ascribe the "dysfunctions, oddities, cruelties, and sadism that pervade the world of life"to the direct agency of the Creator, according to Ayala, "amounts to blasphemy" (p 160). Ayala's advice to religious persons is to accept that evolution by natural selection saves them from this blasphemy. At the same time, Ayala counsels that science has its limits and does not exclude religion or religious understanding. For Ayala, science provides sound understanding of the natural world, while religion speaks to questions of meaning and value that simply lie beyond the domain of any scientific investigation.
Ayala's explanation of evolutionary biology in Darwin's Gift is masterful. He effortlessly explains the conceptual foundations of evolution in sections on natural selection, adaptation, and speciation. With characteristic clarity, Ayala also includes recent results from genomics and molecular biology. The result is a rich portrait of evolutionary biology that is accessible to a wide range of readers. Chapters 3 to 7 in Darwin's Gift are dedicated to a careful explanation of the basic processes of evolution and natural selection, their application to human evolution, and the relevance of new understanding drawn from the study of molecular sequences of DNA and proteins. The incorporation of results from molecular biology is especially valuable to a general audience that rarely sees the intersection of genomics, bioinformatics, and evolutionary biology.
Ayala also includes a final chapter on the history and philosophy of science. While he acknowledges that it is not necessary for the arguments he makes earlier in his book, it is a welcome introduction to ideas of evidence, inference, and change in biology.
Darwin's Gift is an masterful addition to the popular literature on evolutionary biology. Ayala does not present an exhaustive survey of now familiar creationists' objections, nor should he. Instead, he offers in clear and lucid prose an interesting and incisive critique of design based on his rich understanding of both evolutionary biology and Christian theology. Although Darwin's Gift has few imperfections itself, its advice to embrace nature's imperfections and understand them through evolutionary biology is extremely compelling.