CHAPTER 2. THE EMERGENCE OF EVOLUTIONARY THOUGHT

BACKGROUND TO EVOLUTION

Creationism

As should be no surprise to any reader, religious ideas dominated early American thought (Curti, 1980:7). Americans, following the theory of Genesis, believed that God had created man in His image and that man through the fall came to suffer from original sin. This was one way to explain the frequently noticed tendencies for men to be petty and at times cruel, not to mention down-right criminal.

According to the biblical story of the creation, living things constitute a pyramid of immutable species at the top of which stood man himself. This theory draws a basic dividing line between human beings and animals. God gave man the power to reason and this set man above the animals.

Emergence of Evolutionary Thought

France was an early home to evolutionary thought. Georges- Louis Leclerc, Comte de Buffon, ( -1788) was a preeminent figure in French science and also the keeper of the royal botanical and zoological garden since 1739. Buffon opposed Linnaeus and Linnaean taxonomy, and, therefore, many scientists came to see him as the chief obstacle to an effective reform of French natural history (Corsi, 1988:3-4).

Jean-Baptiste-Pierre-Antoine de Monet de Lamarck (1744-1829) was a member of a large family of the lesser provincial nobility. He studied medicine for four years, took to chemistry and mineralogy, and began collecting shells. His main scientific interest, however, was botany. He met Buffon at the Jardin des Plantes and later became his protege. In 1793 Lamarck was elected professor at the National Museum of Natural History. (Newtonian ideas had also affected America. Early American leaders were often deists, Franklin among them. This religion said that God had created the Universe, man included, but that he did not intervene on a day to day basis in the lives of man. This view was influenced by the scientific laws underlying nature as propounded by Newton.)

Taking the mantle of leadership from Buffon, Lamarck became the head of a more traditional group of French scientists. This group opposed the new chemistry of Lavosier and believed in spontaneous generation. The French public looked to Lamarck to revive natural history as a vision of the unity of nature, as against the Newtonian universe (Corsi, 1988:17).

In 1779, Lamarck believed in the idea of decreasing structural complexity. This idea held that classification should proceed from the most complex species to the simplest one. However, Lamarck had serious difficulties in actually producing such an ordered classification. Gradually, he fell back on a hierarchical classification of genera, and slowly lessened his attack on taxonomic systems (Corsi, 1988:44).

Lamarck developed a theory of the inheritance of acquired characteristics that would actually prove, at least temporarily, more popular than that of Char Darwin. His most famous work is his 1809 Zoological Philosophy. The French natural scientist ignored the possibility of random variation. Instead he emphasized that in a new environment all individuals strive to acquire useful habits. These acquired characteristics are then inherited by succeeding generations. Over many generations the species will thus become significantly modified. His best known example is that of the giraffe. According to Lamarck, the ancestors of the modern giraffe stretched their necks to reach the leaves of trees; the effect of the stretching, inherited over many generations, accumulated to produce the long neck of today's species.

Herbert Spencer

Herbert Spencer was an enormously important social thinker. He provided theoretical backing for laissez-faire ideology and was also a precursor of the structural-functionalist school of sociology in America. Spencer wrote of evolution long before Darwin published his famous thesis. In fact, it was Spencer who used the phrase "survival of the fittest." Spencer had been a Lamarckian evolutionist since 1840 and had published his first article supporting transmutation in 1851. In 1855 he published Social Statics.

Spencer pushed forward the idea that Lamarckianism could be the mechanism of both adaptive and progressive evolution, since higher intelligence is the best way to be successful in the fame of evolution. His problem was to convince the scientists of his time that Lamarckism could really work as a mechanism of adaptive evolution. Spencer, however, was not making many converts to Lamarckianism. But then Charles Darwin came on the scene. Faced with the evolutionary theory of Darwin, suddenly Lamarckianism seemed an acceptable alternative. Bowler (1988:64-65) writes that without the intervention of Darwin, Spencer would not have succeeded in his endeavor.

Charles Darwin

Charles Darwin was born in 1809 in the Shropshire town of Shrewsbury. His father was the town's most prosperous doctor while his mother was Susannah Wedgwood, daughter of Josiah Wedgwood of pottery fame. Darwin showed an early interest in natural history and attended the University of Edinburgh for the training of surgeons and physicians. Darwin was very squeamish at the sight of blood and quickly decided that his future did not lie in medicine. Instead, he consolidated his interest in natural history. In the autumn of 1827 Darwin went to Christ's College, Cambridge, his immediate aim to get a B.A. and take up a career with the church. He graduated in 1831.

In 1828 the British government had commissioned the HMS Beagle for a hydrographic survey of South America. After one voyage, the Beagle returned to England for refitting for the next voyage. For the second expedition the commander, Captain Robert FitzRoy, asked for a naturalist instead of a geologist. The word was passed along until it reached Darwin. Darwin, being of independent means, was able to go on this voyage of five years, joining the expedition in Plymouth during the last weeks of 1831.

Some interesting scientific challenges awaited Darwin on his trip. An area of keen interest in natural history was the problem of species distribution. There were obviously different species on different continents. Such facts could only be explained by the creationist model through an arbitrary assumption that each continent was the focus of a "center of creation" that produced only certain types of species. Geologists in particular pondered the meaning of these geographical patterns. Charles Lyell's Principles of Geology (1830-33) was a very important geological text. Lyell rejected the idea of catastrophic earth movements in favor of a gradualist or uniformitarian model of change. He also rejected Lamarck's evolutionism. Lyell created an opportunity for Darwin because Lyell's theory lacked an explanation for how species are geographically distributed worldwide. Lyell thought migration and adaptation would be possible sources of explanation.

Thomas Malthus's Essay on the Principle of Population greatly influenced Darwin. The essay showed that the tendency of any population to breed beyond the available food supply would result in a constant "struggle for existence." However, the crucial factor that converted Darwin to evolutionism was the much more restricted problem of geographical distribution posed by the Galapagos Islands (owned by Ecuador). The Beagle anchored off Chatham Island, the easternmost of the Galapagos group in September 1835. Darwin soon discovered that each island had its own characteristic forms, one of which were the islands' finches. If the creationist view was right then why were there different species of the same genus on the different islands.

The Beagle docked at Falmouth on England's southwest coast in October 1836 and Darwin returned home to Shrewsbury. Ahead of him was the task of writing down the findings from his trip. An intellectual turning point for Darwin came in 1837. Darwin met John Gould, the Zoological Society's taxidermist. Gould informed Darwin the the thirteen specimens of finches that Darwin had collected on the Galapagos Islands were actually thirteen different species. Now that Darwin knew for sure that the finches were distinct species, rather than merely varieties of a single species. Not finding it acceptable that God had created a separate species for each island, Darwin began to believe that the isolated populations had adapted to different conditions on the different islands, thereby creating new species. By the following year Darwin began to see failure to adapt as the key to the transmutation of species. In 1839 Darwin published an account of his voyages. However, he delayed publishing his thesis of evolution for some twenty years for fear of the radical political consequences.

In 1859 Darwin published The Origin of Species. The reaction was immense as everyone knows. However, few people know that this was not his most controversial book. In 1871 he published The Descent of Man, and Selection in Relation to Sex which maintained that man is biologically related to the animals. Darwin rejected the belief, as old as Aristotle, that there is a basic distinction between the human mind on the one hand and the animal mind on the other. Darwin had only hinted at this in his original volume on evolution. In 1872 Darwin came out with The Expression of the Emotions in Man and Animals in which he stated that some human emotions can be understood in terms of man's animal heritage.

With hindsight Darwin's reluctance to publish his work on evolution was justified. The work was too radical for the nineteenth century (and still is today for twentieth century American social scientists). Therefore, most thinkers rejected Darwin's view of evolution. Instead, they accepted other versions of evolution -- versions that were much more congenial in their acceptance of ideas such as God and religion and liberal social change. The alternative ideas came primarily from Lamarck, as interpreted by Spencer.

 

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