Customer Reviews

Evolving the Alien: The Science of Extraterrestrial Life

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This is a book on applied theoretical biology which exhorts science fiction writers and other creators of imaginary worlds to develop more realistic biology for their alien life. However, although the book contains many interesting tidbits and tips to this purpose, there is little systematic practical advice on how to imagine realistic biology. The book does not seem to follow any coherent plan and is instead very discursive and unsystematic. A practical guide to imagining realistic alien life ought to include topics such as the following:

* Possible settings for life to originate, possible bases for biological chemistry in each of these, limitations to expand into other environments.

* Detailed discussions of known environments in the solar system, especially those with enough interesting chemistry that life is conceivable.

* Theoretical discussion of biological niches and strategies appropriate to different circumstances.

* In particular, a discussion of evolutionary psychology and its implications for an intelligent species for many different biological niches. For example, what sorts of things might the members of an intelligent eusocial species find to be pleasurable? What internal conflicts would characterize them?

Although this book discusses these topics, they are not developed in a comprehensive or systematic way and really serve only to tantalize the reader without giving him much that he can really use. Instead, the authors spend lots of space criticizing the alien life of famous science fiction stories without relating them to enough theoretical knowledge that the reader could generalize from these specific cases. For example, they criticize the xenomorph from the movie Alien for having teeth. This they consider implausible because teeth only evolved once in Earth's history, whereas many other strategies for grasping and disintegrating food at the start of the digestive system have evolved in other Earth lineages. Therefore, we would expect aliens not to have teeth but to have their own original mouth parts that may not look like anything familiar. In the first place, this criticism contains no real advice on imagining realistic alien mouths, other than that they should not have teeth, and second, it strikes me that Alien would not have been nearly as horrifying and memorable if the xenomorph did not have teeth. The image of a toothy maw strikes ancient parts of human psychology. We have evolved to find teeth fearsome and a more realistic alien would not have been able to achieve the same effect.

Some things discussion I found interesting were the authors' arguments on the abundance of life in the universe and the evolution of intelligence. They authors argue that the number of physical processes which could support a mechanism for homeostasis and heredity is likely to be truly vast, far larger than can possibly be imagined. Hence, life should be expected in environments very dissimilar from those familiar to us on Earth. I find these arguments to be plausible. The authors also argue that intelligence, as a strategy for propagation, is so monumentally effective that intelligence should be expected to arise inevitably where ever life has arisen. On Earth, the events that lead to the development of life and to the evolution of intelligence may seem to involve many extraordinarily unlikely coincidences, but the authors have an answer to this. They argue that since we have an extremely limited knowledge of the kinds of environments that can support life, there is no way to know whether any of these coincidences was really necessary or that, without them, some very different form of life might have arisen. Any planet which supports life is likely to appear to have extraordinary coincidences in its past, but these may just as well be seen simply as causes leading to the form life presently takes. However, the authors' faith in the inevitable evolution of intelligence, I suspect, is a lot less meaningful than it may sound at first. Since they give no limit on how long it might take for intelligence to evolve, it may be that in most real circumstances a planet might have to support life far longer than any star or other energy source might last.

There is also a discussion on Creationism with refutations of some creationist arguments, but there are many better sources on this topic elsewhere. Discussions like these generally come as random digressions that do not form any overarching argument. Although this book contains some interesting discussions, I do not think they make the book a worthwhile read.