The Challenge of Exoevolution

Article excerpt

How great would be the desire in every admirer of nature to behold, if such were possible, the scenery of another planet.!

Charles Darwin, The Vogage of the Beagle (1839), Chapter XXI

Do life-forms exist on other worlds? Are there intelligent beings living among the galaxies? Have advanced civilizations emerged elsewhere in this universe? These questions were asked by philosophers in antiquity and are now being asked by scientists today.(1) Their answers have a direct bearing on the place our species occupies within dynamic nature.

Over the centuries, several explanations have been offered for the origin of life on this planet. In Western history, the traditional religious belief maintains that this universe, along with everything in it, was divinely created by a personal God in six days about ten thousand years ago. For some Christian religions, this theistic interpretation has been modified to accommodate the scientific theory of organic evolution. Consequently, they speak of theistic evolution to account for the origin and history of life on Earth. However, a divine creation is not acceptable to a strictly scientific and rational search for answers to questions concerning the origin of this universe and life in terms of empirical evidence and logical arguments.

A few scientists and philosophers have maintained that plants and animals exist because of a creative life-force that pervades the otherwise inert matter of nature. Referred to as vitalism, this meta-physical position argues that there is a crucial distinction between matter and life? It results in a dualistic interpretation of nature. Vitalists maintain that this life-force causes matter to take on organic properties resulting in the evolution of life throughout Earth history. Unfortunately, this dualistic position gives priority to a metaphysical principle rather than science and reason.

A third explanation maintains that outer space is filled with cosmic seeds or spores that are capable of creating life-forms wherever they germinate on planets throughout this universe. As a result, this panspermia hypothesis argues that life reached the Earth from deep space and, once these seeds took root, more and more advanced plants and animals emerged on our planet. However, the panspermia hypothesis does not give an explanation for the origin of life but merely places its existence throughout this universe.

Before the writings of naturalist Charles Darwin, it was maintained by most biologists that simple and even complex life-forms suddenly appeared from inorganic matter.(3) The spontaneous generation hypothesis maintained that rats suddenly emerged from rotting wheat, mice suddenly appeared from decaying rags, and amphibians were suddenly formed from mud and slime. Today, there is no empirical evidence to support any claims made by the spontaneous generation hypothesis.

In philosophy, some thinkers have argued that the entire universe is alive, making no sharp distinction between matter and life itself. Referred to as hylozoism, this view of life is so general as to be meaningless. On the other hand, some thinkers have been so bold as to maintain that life actually preceded matter, with matter being merely the residue of life itself.

Charles Darwin (1809-1882)(4) thought that science would not be able to explain the origin of life. However, at the end of the last century, the evolutionary materialist Ernst Haeckel (1834-1919) argued that life and intelligence are likely to exist among the stars.(5)

Since the writings of Darwin and Haeckel, modern biologists maintain that organic evolution explains the origin and diversity of life on Earth as well as its extinction throughout planetary history.(6) In short, physico-chemical development paved the way for the emergence of organic evolution. Therefore, the human animal is merely one species among those countless millions of life-forms that have appeared throughout organic evolution. …