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The discussion about Natural Selection


(This text is part of the complete article. “Selfishness, warfare and economics or integration, cooperation and biology”. Salvucci, E. Front. Microbiology, 2012)

 

The discussion about Natural Selection

 

The cornerstone of the dominant theory is natural selection. Since its inception, the acclamation of natural selection was not a unanimous reaction. Among the criticisms received, we can mention those of Charles Darwin[1], Adam Sedgwick, Aldous Huxley, Karl von Baer, Louis Agassiz, Richard Owen, Lyell, Richard Lewontin, Mivart, Kölliker, Royer, Peters, etc.

 

In Darwin´s work, natural selection takes many forms and nuances. Darwin postulates this “mechanism” generator of new species in a scenario of continued competition. It also takes other definitions as a determinant of character preservation, general process, survival of the fittest, agent, power, cause of extinction, strength. The definitions given for this invisible arm is also varied and their use to explain it all leads to acquire a stunning conceptual flexibility (Cervantes, 2011a).

 

In words of Futuyma: Natural selection is the only mechanism known to cause the evolution of adaptations, so many biologists would simply define an adaptation as a characteristic that has evolved by natural selection” and “any consistent difference in fitness among phenotypically different classes of biological entities” (Futuyma, 2009). We can not define it as a mechanism, given that in a mechanism there are elements known and arranged to ensure a predictable performance. Furthermore, as natural selection would be the generator of species and the insurer of the survival of the fittest, it must also generate morphological novelties.

 

For Dawkins “there is of course no ‘architect’. The DNA instructions have been assembled by natural selection”. However, Natural selection is not an external force or agent, and certainly not a purposeful one. It is a name for statistical differences in reproductive success among genes, organisms, or populations, and nothing more.” (Dawkins, 1975). But, natural selection, i.e. survival and differential reproduction of organisms, is the main controlling agent of evolutionary change (Dobzhansky et al., 1977).

 

Also, Natural selection is at one and the same time a blind and creative process (Dobzhansky, 1973). The idea of selection implies a teleological residue. Selection implies intention since this term refers to a deliberate action of men. If we consider that natural selection is a process, we are allowed to associate it with any natural phenomenon, and we would be allocated for this purpose or intentional phenomenon. The phenomenon (evolution) is confused with the concept that seeks to explain (the selection) (Cervantes, 2011a; Cervantes, 2011b).

 

Schluter (2009), who did not define natural selection, writes: “The main question today is how selection leads to speciation (…) what are the mechanisms of natural selection (…)”. It is assumed that mechanisms of natural selection (that is not a mechanism) are not known. Even though it is generally accepted that natural selection could not only generate all species but also “drive” the evolution, i.e. the generation of new structures, the cause of appearance of the existing body systems.

 

At the same time, natural selection is a statistical difference, cause of adaptations, process, mechanism, the assembler of DNA, the agent that acts over DNA, the result of the adaptations (reproductive success once adapted to the environment), the difference in fitness, the result of the that difference, the differential survival of entities. A concept that is many things at the same time is probably nothing. We can agree that everybody understands natural selection as survival and differential reproduction of organisms. However the term refers to the causes and the effects and takes lot of nuances along literature.  It is a semantic ghost. This indefiniteness made everything seem to be explained but nothing is explained actually. Everything leads us to confirm the existence of pliable natural selection with the existence of living organisms (survivors) and that they are adapted to their environment. That leaves us still at the starting point of evolutionary research (Cervantes, 2011a).

 

Linguistic traps of darwinism began in Darwin’s work but continued through time and spread more confusion. During 70s there was a discussion about the tautological nature of natural selection. Initially, natural selection claimed that in nature not only a few survive, but also that the fittest survive. That is, those that survive are the fittest to survive, because survival means that not all of them do it, surviving means ability to survive and they survive precisely because they are the fittest. It’s a circular reasoning that does not represent any advance in knowledge. What any evolutionary theory should prove is what the laws of evolution are and do not say that the fittest survive. Peters argues that given its inability to make predictions it cannot be called a scientific theory (Peters, 1976). Natural selection is currently used to explain relationships among organisms, without being used in the context of the evolutionary process, i.e., major organizational, morphological, physiological changes and the origin of species. The core of the problem is that, despite the defenses that can be done in favor of natural selection, it does not add any knowledge or information to contribute to the explanation of the process.

 

From the point of view of the renowned philosopher and epistemologist Karl Popper the criterion of demarcation, i.e. a rule that defines when a theory is scientific or not, is its falsifiability. If a proposition is not falsifiable it is not scientific, and his rebuttal is determined by experimentation, the scientific method. As a tautology, natural selection is not falsifiable, and then, with this criterion, it is not a scientific theory (Popper, 1963).

 

For Ehrlich and Birch, in agreement with Popper, darwinism cannot be refuted by any possible observations and it is thus “outside empirical science” (…) It is “an evolutionary dogma accepted by most of us as part of our training” (Erlich and Birch, 1967). A concept that was very vague from the beginning, in a text with little scientific rigor and a lot of ambiguity, was sustained over time and forced to fit the new discoveries.

 

Taking natural selection as correct, it can also lead to inconsistencies in the theory (Bouchard and Rosenberg, 2004). With knowledge of the complexity of the microbial world (natural selection arises from the observation of domestic animals) and the complexity revealed by genetics until today, the excessive eagerness to believe in natural selection is striking.


[1] “I admit . . that in the earlier editions of my Origin of Species I probably attributed too much to the action of natural descent of the survival of the fittest.”—Charles Darwin, The Descent of Man, Vol. 1 (1871 1st ed.), p. 152.

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