A modern evolutionist turns to Darwin’s work again and again. This is not surprising, since the roots of all our evolutionary thinking go back to Darwin. Our current controversies very often have as their starting point some vagueness in Darwin’s writings or a question Darwin was unable to answer owing to the insufficient biological knowledge available in his time … We turn to his work again and again, because as a bold and intelligent thinker he raised some of the most profound questions about our origins that have ever been asked, and as a devoted and innovative scientist he provided brilliant, often world-shattering answersWho Is Darwin and Why Was He So Important?
On the Origin of Species ushered in a revolution of thought clearly divided before and after 1859.
· Darwin refuted the belief in the individual creation of the species’ by establishing the concept ‘that all life descended from a common ancestor.'
· 'Darwin argued that humans were not the special products
of creation but evolved according to
principles that operate everywhere
else in the living world.’
· ‘Darwin upset current notions of a perfectly designed, benign natural world and substituted in their place the concept of a struggle for survival.’
· Darwin undermined ‘Victorian notions of progress and perfectibility’ by demonstrating ‘that evolution brings about change and adaptation, but it does not necessarily lead to progress, and it never leads to perfection.’
· ‘Darwin introduced the concept of probability, chance, and uniqueness into scientific discourse’ and by doing so changed the course of the philosophy of science, which until that time, was based on a methodology of ‘mathematical principles, physical laws, and determinism.’
· Darwin’s significant corpus of works ‘embodied the principle that observation and the making of hypotheses are as important to the advancement of knowledge as experimentation.’
Darwin produced ‘original’ books on ‘experimental biology’ near the end of his life and ‘equally outstanding work on the adaptation of flowers and on animal psychology, as well as his · competent work on barnacles and his imaginative work on earthworms. In all these areas Darwin was a pioneer…’
· Darwin’s ‘sound theory of classification’ is still employed by most taxonomists today.
Darwin’s biogeography, which emphasized ‘the behavior and the ecology of organisms as factors of distribution’, was ahead of its time.
Darwin's Theory Actually Consisted of Five Interlocking Theories
Ernst Mayr has long held that: ‘What Darwin presented in 1859 in the origin was a compound theory, whose five subtheories had very different fates in the eighty years after Darwin.’ Mayr points out: ‘Darwinism cannot be a single monolithic theory’ because ‘organic evolution consists of two essentially independent processes … transformation in time and diversification in ecological and geographical space. The two processes require a minimum of two entirely independent and very different theories.’ My point of inquiry; is transformation in time equivalent to evolution by common descent, and, is diversification in space equivalent to natural selection? According to Mayr I think I the two reversed: ‘Darwin treated speciation under natural selection in chapter 4 of the Origin and that he ascribed many phenomena, particularly those of geographic distribution, to natural selection when they were really the consequences of common descent.’ Mayr proceeds to break Darwin’s theory into five parts:1. Evolution. ‘The world is not constant nor recently created nor perpetually cycling but rather is steadily changing and that organisms are transformed in time.’
2. Common descent. ‘Every group of organisms descended from a common ancestor.’
3. Multiplication of species. ‘Explains the origin of the enormous organic diversity.’
4. Gradualism. ‘Evolutionary change takes place through the gradual change of populations and not by the sudden (saltation) production of new individuals that represent a new type.’
5. Natural selection. ‘Evolutionary change comes about through the abundant production of genetic variation in every generation. The relatively few individuals who survive, owing to a particularly well-adapted combination of inheritable characters, give rise to the next gene
Darwin’s Theory of Natural Selection
Whether one believes it was March 1837 or July 1837, Darwin ‘had firmly accepted evolution by common descent.’ It was September 28, 1838 when Darwin, reading Malthus, “at last got a theory by which to work.” That theory was to be later called natural selection. To answer the question regarding the process by which Darwin arrived at such a revolutionary theory as natural selection, Mayr chooses ‘to reconstruct Darwin’s explanatory model of natural selection and then study separately the history of each of its individual components.
Darwin’s Explanatory Model (of evolution through natural selection)—Mayr identifies five facts:
1. ‘Potential exponential increase of populations (superfecundity) (Source: Paley, Malthus, and others)
2. ‘Observed steady-state stability of populations (Source: universal observations)
3. ‘Limitation of resources (Source: observation reinforced by Malthus)
4. ‘Uniqueness of the individual (Source: animal breeders, taxonomists)
5. ‘Heritability of much of the individual variation (Source: animal breeders)
And three inferences:
1. ‘Struggle for existence among individuals (Author of inference: Malthus)
2. ‘Differential survival, i.e. natural selection (Author of inference: Darwin)
3. ‘Through many generations: evolution (Author of inference: Darwin)’
Mayr lists four areas where ‘Darwin’s beliefs changed moderately or drastically
1. ‘The gradual replacement of the assumption that all individuals of a species are essentially
alike by the concept of the uniqueness of every individual.
2. ‘A shift from soft toward hard inheritance.
3. ‘A changing attitude toward the balance of nature.
4. ‘ A gradual loss of his Christian faith.’
What Is Darwinism?
Mayr explains that Darwinism is many things to many different individuals and ‘that Darwinism is not a monolithic theory that rises or falls depending on the validity or invalidity of a single idea.’ Mayr continues ‘this monolithic tradition actually started with Darwin … who often spoke of his “theory of descent with modification through natural selection” (1859:459) as though the theory of common descent was inseparable from that of natural selection.’ To elucidate this difficulty with the naming and usage of the term Darwinism, Mayr lists several categories of use:
· Darwinism as “Darwin’s Theory of Evolution” – this is the most commonly misused and does not specify which element of Darwin’s bundled set of theories it is referring to and is ‘utterly misleading’
· Darwinism as Evolutionism – since evolutionary thought existed before Darwin, it is incorrect ‘to refer to evolutionism as Darwinism.’
· Darwinism as Anticreationism – ‘denied the constancy of species and, in particular, special creation … the separate creation of every feature in the inanimate and living world.’ Mayr lists two groups of anticreationists: the deists who believed in a God as ‘a remote lawgiver’ whose non-interference in the world was supplanted by the existence of his laws which governed creation. The idea of evolution was only acceptable as a ‘transformational evolution – the orderly change in a lineage over time, directed toward the goal of perfect adaptation … Agnostic anticreationists explained all evolutionary phenomena without invoking any supernatural agents.’ In the Origin Darwin argued in materialistic (a naturalistic explanation) manner against creationism. Darwin’s “one long argument” was against ‘special creation.’ Origin of Species was Darwin’s “species book.” Natural selection was only discussed ‘in the first four chapters’ while ‘in the remaining ten chapters,’ are ‘exclusively devoted to documentations for common descent.’
· Darwinism as Anti-ideology – ‘essentialism (typology), physicalism (reductionism), and finalism (teleology) were not an aspect of Darwin’s thought in Origins.
· Darwinism as Selectionism – ‘Natural selection as the mechanism of evolutionary change was not universally adopted by biologists until the period of the evolutionary synthesis (1930s-40s); however, natural selection was the key theory in Darwin’s total research program …’
· Darwinism as Varitional Evolution – Darwin’s ‘concept of evolution’ was not transformational nor was it saltational. Since Darwin thought within populations, variation for him was ‘unlimited.’ This was the difference between variational evolution and the essentialism of ‘Lyell, Sedgwick, Herschel, and others’ including contemporary thinkers such as Kitcher.
· Darwinism as the creed of the Darwinians – ‘This choice of defining Darwinism is more often favored by philosophers and historians than by biologists.’ It must be remembered; there is ‘nothing … more essential’ for Darwinists ‘to decide whether evolution is a natural phenomenon or something controlled by God.’ Such is the defining aspect of Darwinism.
Darwinism as a New Worldview – mirrors the arguments made of Darwinism as an ideology, but are directed at a historian of ideas, J.C. Greene.
Darwinism as a New Methodology – ‘Darwin’s method was to present the evidence on which he based his inferences, and he used these inferences to support his conjectures. The greater the number and the variety of pieces of evidence he could cite, the more convincing the inferences became.’ In addition, Darwin was a bit of a pluralist when engaged in argumentation – he used what would help him make his point. Mayr elaborates: ‘The version of Darwinism that developed during the evolutionary synthesis was characterized by its balanced emphasis both on natural selection and on stochastic processes; by its belief that neither evolution as a whole, nor natural selection in particular cases, is deterministic but rather that both are probabilistic processes; by its emphasis that the origin of diversity is as important a component of evolution as is adaptation; and by its realization that selection for reproductive success is as important a process in evolution as selection for survival qualities.
The Pluralism of Darwinism – ‘After 1859 (until about 1930) … Darwinism for almost everybody meant explaining the living world by natural processes.’ After the 1940s and ‘the evolutionary synthesis the term Darwinism unanimously meant adaptive evolutionary change under the influence of natural selection, and variational instead of transformational evolution.
I wish to cite the thought and writings of the
scholarship of Charles Darwin for provided
an invaluable source of ideas and insights
never before conceived in human history
as an explanation of the ongoing process
of evolution and to the equally enormous
task of taking the monumental work of
Darwin and explaining it in a way in which
the curious laymen might begin to understand
such a significant undertaking: I recognize
and acknowledge the painstaking labors of
Ernst Mayr, who spent a considerable amount
of his life time studying and extending the work
of Darwin for the exclusive intellectual
contribution made to make the creation of
this blog posting possible.
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