Ussher-ing in Evolution
It is hard to think of a single book that has had greater impact on science and society than The Origin of Species. At the time George Eliot remarked that it "makes an epoch", and today Neo-Darwinism's great champion Richard Dawkins is of the opinion that it did nothing less than unlock the meaning of life; that it started the process that has enabled science to replace the constant human search for 'why?' with the question of 'how?' A bold claim perhaps, but there is no doubt that Darwinism and Neo-Darwinism have done an enormous amount to unravel many of humanity's myths of its place in nature. Equally, it is a mistake to assume that Darwin's theories proposed in The Origin of Species were entirely revolutionary. Like all scientific discoveries, Darwin was drawing on a tradition of thought that question the orthodox view of the nature of the world.
It is useful at this stage to summarise briefly the theory at the heart of The Origin of Species. The full title of the book when published was the snappy On the Origin of Species by means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. In extreme summary, it maintained that species had not been independently fabricated by a Creator, but had arisen from a single common ancestor (or at least very few common ancestors) and had changed their form through "descent with modification". The chief agent of this change, according to Darwin, was the process of Natural Selection. Natural selection refers to the process by which environmental pressures lead to varying degrees of survival and reproductive success among individuals of a population of organisms with different hereditary characteristics. Those individuals with characters that are better suited to existence and reproduction in a particular environment and with relation to the other organisms in that environment (i.e. that are beneficial in what Darwin referred to as "The Struggle for Existence") are more likely to survive and produce offspring. This is often referred to (though not initially by Darwin) as "the survival of the fittest", a phrase which will be examined later. Given that there is differential survival of differentiated individuals, the slow change of individuals over many generations under sustained environmental pressure will lead to the differentiation - i.e. origin - of different species. A range of geographical, physical and behavioural factors will either increase or decrease the likelihood of speciation.
With the discovery of the laws of heredity, genetics, and developments in evolutionary theory, the term 'natural selection' has taken on a different hue and a more refined definition than that proposed by Darwin. However, much has been discovered since the time of Darwin, and one cannot conduct a scientific appraisal of Origin purely in the light of what has been established since, any more than it is possible to criticise the political writings of the nineteenth century for not taking into account twenty-first century statistics and opinions. Origin must be approached largely as a historical document, and as a scientific development on what was known at the time. Today there are countless books discussing modern evolutionary theory (see Missing Links and Further Reading).
Just as much has been learned about evolution since Origin, so Darwin represented an established (but still controversial) tradition of evolutionary thinking. There was, however, much dogma to overcome. The notion of Creationism - that the universe had been bought into being by Divine force - was, and still is, imbedded at the heart of religious belief the world over. For Western European thought, this 'fact' was enshrined in the bible, and in the mid-seventeenth century, Archbishop James Ussher (1581 - 1656) had calculated, through the Old Testament series of 'begattings' and some spurious mathematics, that the world was created in 4004 BC. The English biblical scholar John Lightfoot was so stimulated by this revelation that he additionally calculated that the exact time was October 26 at 9.00am. Absurd as this all seems now, Ussher's date was widely accepted and included in the page margins of many editions of the King James Bible. Indeed, the term 'prehistoric' did not exist until the mid-nineteenth century, and until the notion that the history of the universe was a short period of time sandwiched between endless tracts of eternity was replaced by the recognition of the enormous age of the earth, evolutionary theories stood no chance of being seriously entertained. Moreover, a central tenet of Christian faith was the infallibility of God, and the world must be an unaltered replica of that which God had created. No species could be lost or altered - both change and extinction were impossibilities. Fossils, therefore, posed an awkward problem, one that was overcome by the notion that God had destroyed forms of life in disasters such as the Biblical Great Flood. As more and more fossils in distinct geological layers and of increasing complexity came to light, this Catastrophism gave rise to the idea of Progressionism. Progresionism
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