Truth versus usefulness

Alvin Plantinga

As I said in a previous post, natural selection is the statistical observation that, in general, individuals better adapted to their environment tend to leave more descendants than those less adapted. It is, therefore, a question of usefulness. A trait that will increase the reproduction of an individual is, in principle, statistically favored by natural selection.

In my popular science book published in Spanish (Biological evolution and cultural evolution in the history of life and man) I mentioned that 

Evolution acts in the same way, both on life and on culture, although its way of acting is adapted to the specific environment on which it is applied (genes, nervous systems or cultural elements). 

Mistakes regarding natural selection

Charles Darwin

Since Charles Darwin coined this term, and included it in the title of his famous book, published in 1859, the term natural selection has been poorly understood, especially by non-specialists. Let’s review a few of the most frequent mistakes:

• Natural selection is a force that acts on living beings to cause evolution. This is not true. Natural selection is not a force, nor an object, nor an interaction, nor a phenomenon. It is simply a statistical observation. What is observed is the fact that, in general, individuals better adapted to their environment tend to leave more descendants than those less adapted. Nothing else. It is, therefore, a matter of common sense, not the result of the external action of a mysterious force.

Evolution in the twenty-first century

A little over thirty years ago, during the eighties, some of the fundamental concepts of evolution seemed to be quite clear. Let us look at a few:

• The DNA of every living being is an encrypted message that perfectly describes how to build the corresponding phenotype (the adult individual). All the information is in the genes. (Mechanistic reductionism).
• Most DNA is unnecessary (junk DNA) and has been accumulated due to errors and repetitions in the transcription of the genomes of living beings.
• The best metaphor to represent the organization of a genome is a set of beads on a string.
• Genes are the repositories of inheritance, and each gene specifies a biological function.
• Evolutionary processes take place through random mutations that act on a single gene, which are subject to natural selection, which results in small incremental increases in the adaptation of living beings to the environment.

Darwin’s mistake

Charles Darwin

Consider the following paragraph by Darwin in The descent of man (chapter 5):

With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man.

It seems incredible that, after a lifetime devoted almost exclusively to meditate on his theory of evolution, Darwin made the mistake of applying it wrongly to humans, as is clearly demonstrated in the paragraph I have just quoted.