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It is always appreciated the mention of the theory of evolution in the generalist press, even if it is to attack it. If the person doing it is an educated man, although not versed in science, his opinion or point of view may reflect that of many other professionals who, in fields other than science, be they lawyers, notaries, engineers, etc., give by good his arguments. And also, that in other cases it leaves people confused who, without accepting the ‘solution’ presented, have no better response to their arguments than silence. Unlike the article by some colleagues published in this medium, I do believe that the specific arguments of this type of article must be answered.
One of the first things science teaches, and one of the most often forgotten things, is the concept of variability. Creationists ‘haylos’ of various types and continents, but they could be reduced to three categories and their intermediate states.
They are those who believe in the literal content of religious writings that, in the case of some important current religions, is limited to what comes in Genesis, mainly. Arguing with them does not make much sense, since their life tends to a permanent contradiction. For example, they can use Magnetic Resonance in their medical treatments without caring that the same principles that allow its operation are those used to calculate the age of the Earth. In your case, claiming that the Earth is 6,000 years old is a toast to irrationality.
They are the ones who, accepting the scientific explanation of the generating process of biodiversity, nevertheless pose two ‘exceptions’, which would be the origin of life and the transition to the human species, for those who demand a special intervention (read God). One defender of this position was the Jesuit Teilhard de Chardin, who reconciled various orthogeneticist entelechies with racist and eugenicist positions. Pretending that the origin of life or the appearance of humanity require special interventions, beyond the forces of nature, is still an arbitrary position that clashes deeply with everything that has been achieved with scientific knowledge.
The third category, more recent, but with egregious contemporary examples from Darwin and Wallace, are the so-called scientific creationists. Don’t think this is an oxymoron. They are scientific researchers who regularly publish in good scientific journals and are also creationists. It is from these authors that the most recent counter-evolutionary arguments are fed.
They consider that there is not enough fossil evidence of evolutionary transitions. Todd C. Wood, co-author of the rice genome sequence, published in Science, is one of the main representatives of Baraminology, a variant of creationism that partially admits evolution, but always from created entities.
For them it is important to point out the discontinuity that exists between large groups of organisms, which would mark the guidelines of creation. Thus, there would be an initial feline created, from which all current felids would descend by mutation and natural selection; felids unrelated to canids (for example), which would descend from an ancestral canid, also created expressly. And so for all large groups: we would have a primal can-Adam or felix-Eva, etc. product of a divine intervention in their origin.
The truth is that the fossil record does show transitory organisms between fish and amphibians and reptiles, and of these with birds. Not to mention that one of the best documented paleontological records is that of the evolution of the horse. It is possible that whoever thus argues about the discontinuity of the fossil record expects that the examples of evolutionary transition are like the platypus, by way of evolutionary chimera. Yes, nature is capricious, but not as some want to imagine it.
A little more sophisticated is the argument proposed by Michael Behe, which is also often echoed by these types of articles. It is the thesis that much of the biochemical complexity that we find in the cells of living beings is irreducible and non-transitional. That is, there would be no way to reach the current complexity through gradual transitions, since none of the supposed ‘previous stages’ would be functional or have adaptive value.
Behe’s ‘irreducible complexity’ does not hold up as one delves into the biochemistry of cells. With one unraveled, there is no reason to think that they cannot all be unraveled. It all depends on the time and money available to investigate.
A good example is the evolution of glucocorticoid receptors that have been investigated by J. Thornton et al. As he himself points out in a letter to Carl Zimmer in response to Behe’s comments, he “ignores the fact that adaptive combinations of mutations can and do evolve in pathways that involve selection-neutral intermediate stages.”
Furthermore, these researchers have experimentally characterized how the evolution of an ancestral protein can go through neutral states and that some mutations that are called ‘permissive’ can cause that, once inserted into the protein, other mutations are tolerated and that they change and optimize the new function, mutations that in isolation are deleterious. The truth is that mechanisms and ways by which the supposed irreducible complexity of Behe can be reached in a natural way (mutation and selection) are currently known.
In summary, a) there is continuity in the fossil record and b) there are enough evolutionary mechanisms to explain the supposed irreducible complexity.
What is already more difficult to understand is the bias in the reasoning that leads to demand divine intervention in human evolution. Well, what creationists seek is that the living world is evidence of the existence of God. For better or for worse, the existence of God is an unspeakable and undeniable, as the Spanish philosopher Manuel Sacristán has already pointed out: put to the case, one cannot empirically deny the existence of an abracadabrante being, but at most affirm that there is no sufficient evidence to admit its existence, or that postulating it lacks explanatory value for the world we know. The philosopher of science, Karl Popper would celebrate this reasoning, if he had known it.
By way of conclusion, one can believe in God, but the evolution of species is not evidence of it. And yes, evolution is a fact and we continue to delve into the mechanisms of its processes.
This article was originally published on The Conversation. Read the original.
Antonio G. Valdecasas does not receive a salary, nor does he carry out consulting work, nor does he own shares, nor does he receive financing from any company or organization that can obtain benefit from this article, and he has declared that he lacks relevant links beyond the aforementioned academic position.