The Paradigmatic Shift from Fixed Species to Evolution
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The Paradigmatic Shift from Fixed Species to Evolution

A history of Pre-Darwinian paradigms and evolutionary paradigms and the conflict of diversity of species.

William Paley’s ideas of Natural Theology were the norm for pre-Darwin thinking on the diversity of species. Paley held an essentialist view of the natural order of things based on the philosophical writings of Plato. Plato said that all things have an origin based on a form and what we see in our world are but reflections of those forms like shadows on the walls of a cave. Paley formalized this concept with the introduction of the Pyramid of Logic. This design of adaptation goes from God at the top of the pyramid and descends toward chaos inferring a loss of the divine original model. This is based on a static world view which essentialists cling too. This ideal was further propagated by other common world views such as the age of the world, reckoned by the bible, being only about eight thousand years old. These views were compounded by the precepts of Uniformitarianism that stated universal laws never change. That is to say that the causal agents of the past are the ones still at work today.

Since it was God who created all species the presence of complex features, such as the eye, and the variability of species was easily explained. That is how God wanted it.

With the discovery of species in the fossil record that no longer existed this idea of the fixed species was brought into question but Cuvier was quick to elaborate on his Catastrophism theory. This idea states that the species that do not exist any more were victims of Gods wraith and succumbed to the forces which he imposed on them. These kinds of events were documented in the Bible as well, most notably the great flood. This seemingly viable answer had no need for evolution as a basis for species variability and seemed to satisfy most arguments and was held as the truth for some time.

After some time the ideas of fixed species gave way to other concepts like Buffon and his ideas of transmutation which paved the way for Lamarck’s theories of spontaneous generation with a predetermined evolutionary track. This idea of change coupled with the mechanism of Inheritance of Acquired Characteristics was later termed orthogenesis. Orthogenesis was a powerful concept that was responsible for the shift in paradigm from fixed to mutable species. It wasn’t until twenty years after Darwin’s trip around the world on the HMS Beagle that another concept for variation and complexity of species was introduced.

The Darwin / Wallace hypothesis of natural selection is widely accepted today but at its introduction it was highly criticized and ridiculed. It was even heretical which is what kept Darwin from publishing it earlier. He flipped the proverbial Paley pyramid and sundered the notions of fixed species and orthogenesis. The debate over Natural selection verses orthogenesis raged for many years and still does in some circles. The weakest point of Darwin’s theory was he had no mechanism for change. We now know that mechanism to be genetics but that didn’t help Darwin or Huxley (Darwin’s bulldog) back then.

The Natural Theology concepts of essentialism and catastrophism can be seen in the Darwinian concepts of marginal zone evolution and adaptive radiation. These two Darwinian concepts are not mutually exclusive. They are closely related and can give insight relating to earlier theories. Marginal zone evolution suggests that where a species may thrive in a particular niche, there will be outlying areas occupied by what is termed peripheral isolates. A species may reach equilibrium in a specific niche and undergo little adaptive change for a long period of time, hence a fixed species (essentialism). The adaptation happens in the periphery isolate populations in what can be a relatively short period of time when talking about adaptive change. This now adapted species, different from the original, radiates out from the population of origin and eventually replaces the predecessor species. When that radiation covers the areas of the original species the fossil record shows a seemingly abrupt change in species form. This idea, which can also be likened to punctuated equilibrium, can demonstrate causality for what appears to be gaps in the fossil record. The idea that a disaster like a flood or a comet has to have occurred (catastrophism) is no longer necessary. That is not to say that catastrophism has no place in modern theory, such as the dinosaur killing comet of which there is evidence, but it no longer can be invoked hap-hazardly in lieu of a better explanation.

The Natural Theology take on complexity of features held that a structure so complicated as the eye could not possibly exist with out divine providence is no longer viable as there exists a more complete fossil record. To say god must have created the eye is to ignore the physical evidence to the contrary. It now becomes a matter of interpretation of that evidence. Now that even Pope John Paul II has ratified the basic concepts of evolution, Theologians must turn to another explanation of Gods workings in evolution. For this they look to intelligent design. Now that the eye has a fairly well established fossil record, Natural Theologians are fixated on the flagellum of a human male sperm. As it is the only known example of a free rotating feature, they have rallied around it and dare godless anthropologist to explain it. The belief is held that since no single part of the flagellum is useful without the rest that it must have been created by a higher power. I recently saw a show about this on the Discovery Channel where they finished every explanation with admonitions “...now this is what I call hard science” and “I’m a scientists and this is, beyond a doubt, proof of gods existence”. From a Darwinian point of view tempered with the experience of all those who came before us, we can safely assume that even though there is no other precedence for this structure in nature, that an answer to this question will present itself in the future. For now the mousetrap analogy, makes for good lip service to the flagellum debate. The idea that a mousetrap must have all of its components to work is not in dispute. That those components of the flagellum can not be derived from anywhere else is what makes wearing the spring from the mousetrap as a tie clip so funny. The truth is that cell specialization can be traced and intelligent design leaves a lot to be desired.

Natural variability is a lynch pin of the differences between the two paradigms. The variability of species as described by Orthogenesis says that species are all derived from differentiated protoforms that evolve with a specific intent toward a predetermined form. Evolution on the other hand shows us that individual forms are derived from the pressures of natural selection and other forces through a series of common ancestors and adaptive mutations. There is no predetermined form or even ideal form as per the adage; Evolution is not an engineer but a tinkerer.

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