Criticism current biology

Foreword to On the Origin of Species by Means of Natural Selection, by Charles Darwin

The history of Darwinism since the appearance of On the Origin of Species confirms its relevance today and the urgency of assimilating it within a higher and more complex theoretical system, of which it will undoubtedly be one of the essential pillars. The history of Darwinism so far (i.e. the history of modern biology) includes four periods.

1. The initial period of expansion of Darwinism (1860-1900)

During the first period, the views of Darwin received active support from eminent biologists such as Thomas Huxley and Ernst Haeckel. Darwinism was accepted by scientists and educated people in general for what it really was: the scientific truth of the time (the biological theory that integrated most knowledge and that was truest). Furthermore, it stimulated biological thought and opened new areas of research, so the whole of biology was raised to a new level in terms of its problems and concepts.

Charles Darwin (1809-1882)

Indeed, On the Origin of Species has the essential double merit of explaining, through the “transmutation” of species, the considerable facts that Darwin had observed in his youth (gradual differences shown by species in South America with changes in latitude; relations between island species of the same archipelago and between those of the archipelago and the continent; the comparison between armadillo fossils and living armadillos, etc.) and of revealing -by analogy with the artificial selection practiced by humans in animal breeding- the mechanism of this transmutation: natural selection. But the basis of truth of Darwinism was also shown in several major consequences.

First, it provided the key to the great body of biological knowledge that had been established previously: namely, botanical and zoological taxonomy. Indeed, only by accepting the common origin and the gradation of kinship of all plant species and of all animal species can one explain the fact that plant and animal species can only be classified satisfactorily and unequivocally through a tree-like system of branches of decreasing categories, in which the species included in any category (genus, tribe, family, order, class, type) possess, in addition to their distinguishing features, all those of the higher categories.

Charles Lyell (1797-1875)

Second, the evolution of species established (if not discovered) by Darwin explains fossils as remains of ancestors of living species, thus agreeing with Lamarck and disagreeing with Cuvier, and -with the help of the long history of the Earth by Charles Lyell, the creator of modern geology and a great friend of Darwin- stimulated palaeontological studies. Since then, the fossil register has been increasingly enriched and has been dated with increasing accuracy. Consequently, remains that correspond to the originary species of the classes of vertebrates (bony fish, amphibians, reptiles, birds and mammals) have been discovered and some series of remains have been ordered, making it possible to follow with great precision the evolution of some groups towards current forms (classical examples are horses and elephants). In particular, an increasing number of remains of hominids have been discovered, laying down the phylogenic lines that (according to Darwin’s inductions) link humans and the current species of great apes (pongids) to a common ancestral species, until the phylogenic tree of the superfamily Hominoidea was established with reasonable plausibility. In summary, Darwinism added a time dimension to the natural system of animals and plants established over the previous century by the applied work of the taxonomists. In other words, the dates on which the ramifications of the classification tree took place were specified. Now a phylogenic tree, it took on meaning and became an understandable result.

Similarly, the theory of biological evolution allowed important observations of comparative embryology to be satisfactorily interpreted. The eminent German embryologist Karl Ernst von Baer noted that the lower the age of the embryos of different classes of vertebrates, the more they resemble each other. Darwin rightly attributed this similarity between embryonic stages to the existence of remote common ancestors.

Ernst Haeckel (1834-1919)

The great Darwinist Ernst Haeckel went a step further by enunciating his famous recapitulation theory, according to which the embryonic development of all living beings (ontogenesis) recapitulates the evolutionary history of their ancestors (phylogenesis). Despite the superficial and almost always retrograde criticism to which it has been subjected in the 20th century, precisely by the Neo-Darwinists, I think this principle contains a profound thread of truth that must be specified, developed and broadened: the close relationship that always exists between processes of phylogenesis (the origin of the first living being of each type), ontogenesis (the origin of each living being of the type) and physiology (their maintenance in each moment). This relationship between ontogeny, phylogeny and physiology has allowed these three biological areas to be clarified by each other. Evolutionary biology gave great impetus and unsuspected importance to the studies of embryological processes.

In conclusion, we can say that in the last century Darwinism broadened and remodeled the most diverse biological areas and directly or indirectly led to the birth of new biological disciplines. So much is this so that just as Darwinism accounts for all previous biology, it also strongly influences post-Darwinist biology. For example, the problems and theories of Darwin and Pavlov are closely related by the fact that they both dealt with the same type of living being: animals. The former studied their phylogeny and the latter the ontogeny of their conduct. It can thus be said that, thanks to Pavlov, psychology was impregnated by Darwinism. Even the most positive contributions of Freud show the influence of Darwin; an example is his evolutionist way of considering the human psyche, shaped by its history and by the influence of the social world. This fecundating capacity of Darwin’s thought shows its great basis of truth, and therefore its general applicability. Moreover, given the essential unity of all living beings, I am inclined to think that the modern areas of biology that have been mainly developed independently from Darwinism (such as biochemistry, genetics, cytology and immunity) are seriously limited in their progress, side-tracked from their genuine problems, due to their lack of evolutionist thought. In fact, in order to convert the enormous wealth of specific disconnected data accumulated by these disciplines into coherent theoretical thought, it is necessary to stop considering exclusively the physical and chemical phenomena produced by living beings and to consider also the agents of these phenomena (the living beings involved: cells and proteins) from an evolutionist perspective. But this brings us to the next period.

2. The period of repudiation of Darwinism by classical genetics (1900-1930)

During a second period stretching from 1900 to 1930, as a reaction to the scientific fecundity of the theory of evolution, Darwinism was discredited by many biologists and educated people in general. The history of this temporary discrediting of the evolutionary theory is highly significant and reveals how superficial the understanding of the theory still was.

Gregor Mendel (1822-1884)

At the turn of the century the laws of Mendel and chromosomal mutations led the first geneticists to boldly deny the theory of evolution of species by means of natural selection but these findings were actually additional evidence of the theory because they confirmed a postulate that is implicit in natural selection: the fact that children tend to resemble parents and that the characteristics acquired by parents in the course of their lives do not influence the congenital capacity of their children. It is now obvious that demonstrating a level of strictly cellular inheritance (to which both the laws of Mendel and chromosomal mutations contributed) was in line with the discovery of the continuity of germ plasm made by the Darwinist August Weismann in 1892. This order of ideas was certainly opposed to the Lamarckian interpretation of evolution, but carried water to the mill of Darwinist thought. Let us now consider the curious fact that a discovery that was profoundly consistent with Darwin’s theory could have been accepted for a time as conclusive evidence against it. I believe that this scientific error probably occurred for two reasons, a circumstantial one and a more profound one, as we will see below.

I am inclined to think that the circumstantial reason was an inconsistency of Darwin with his own theory. Indeed, in his book The Variation of Animals and Plants under Domestication (1868), Darwin set out a theory of biological inheritance in which he sacrificed his theory of natural selection to the Lamarckian interpretation of evolution, according to which species are modelled by the transmission to offspring of characteristics acquired by parents in the course of life

August Weismann (1834-1914)

Darwin proposed this theory of inheritance with all types of reservations (obviously without conviction, and as a mere provisional hypothesis). It was certainly very contrived, but even more contrived (and I think in the same direction) was the theory of genes that was based on the chromosome theory of inheritance. Therefore, when challenging Darwinism the founders of genetics in the 20th century made the mistake of identifying a particular hypothesis of Darwin (his theory of inheritance) with his general thought (the evolutionary theory of natural selection), despite the fact that that the two theories are independent and, indeed, mutually contradictory. Darwin’s was probably reluctant to totally sacrifice the Lamarckian view because important facts that seemed unquestionable raised problems that were still beyond the scope of the theoretical thought of the period and he failed to perceive that they were inconsistent with natural selection. I am referring to the question of how, always, in each of the myriad species, an animal emerges from a cell perfectly adapted to its specific medium. This problem, which the hypothesis of gemmules attempts naively to address, has since then worried some biologists, who reject Darwinism in favour of Lamarckism (as Darwin first did unwittingly). But I am firmly convinced that the true and profound problems raised by Lamarck must be resolved by extending the theoretical underpinnings of Darwinism. However, instead of addressing problems of this order, 20th century genetics (which undoubtedly, like Lamarckism, has an important basis of truth) has decided to ignore them.

Jean-Baptiste Lamarck (1744-1829)

A second factor helped to discredit Darwinism in the first third of the 20th century and continues to influence the development of biology. The enormous expansion of agriculture and industry thanks to technological advances and the disorientation caused by the momentous discoveries of the turn of the century, which denied some of the basic tenets of classical physics and chemistry, helped disrupt the regular progress of science, and in particular of biology. Scientists therefore ceased to master the theoretical and practical progress of science, which has since then been conducted in a disorderly way. Indeed, the boom of complicated and subtle techniques that normally pursue objectives of immediate interest posed by productive activity (providing data that are difficult to interpret) coincided with a certain mistrust of rational thought arising from the crisis of theoretical growth of physics and chemistry.

Accordingly, the cross-fertilization between specific research and theoretical thought (a characteristic of the healthy progress of science from Galileo to Einstein) was largely interrupted; it ceased to be the main objective of scientists, and research was aimed at fragmenting knowledge rather than integrating it. The 20th century has seen the increasing reign of specialists and experts and a considerable proliferation of new, disconnected “sciences”.

Darwinism accounts for all the knowledge, answers all the questions of previous knowledge, and explains the living being rationally, i.e. in its relations with its medium, with the reality that is coherent for it and with the history of that reality. Specialization has clearly turned biologists from this genuinely scientific line of thought. Specialists have a concept of science, a working method and an interpretation of objective reality that are diametrically opposed to those of Darwinism. Indeed, in their efforts to concentrate on their small area of knowledge, specialists tend to treasure their latest discoveries and attain the most perfect mastery of techniques in their small area of experimentation. However, they fail to study the scientific tradition in their field, which is essential in order to understand the meaning of the results of their work and to orient their problems: doing so is beyond their scope because it involves an integration of thought that is contrary to specialization. Therefore, the fragmented and fragmenting knowledge of the specialist necessarily becomes ahistorical. Moreover, the specialist ignores the evolutionary coherence of all the entities and processes and, instead of seeking to understand something by focusing with the proper perspective on the external processes that led to its emergence and that maintain it, seeks to discover in its intimacy something magic (isolated from reality) which gives a key to it. Still in the field of biology, we see that while Darwin sought to understand an animal species in terms of the medium, biologists contaminated by specialization seek to understand the animal solely in terms of the germ cell and, more specifically, of its chromosomes or its nucleic acids. However vainly creationist it is, this investigation has of course accumulated a wealth of facts that are potentially of great value, but they cannot be interpreted (subjected to a theory that can provisionally guide new experimentation) if they are not coherently related to the rest of reality, if the order of ideas initiated with Darwinism is not extended to them.

3. The period of eclectic appeasement between Darwinism and genetic theory (Neo-Darwinism) (1930-1950)

During the previous period, characterized by a predominantly hostile attitude to Darwinism, it continued to be followed in fields whose specialized object was biological evolution, such as palaeontology and anthropology. These sciences probably formed the bridgehead from which Darwinism undertook the reconquest of science in the 1930s and 1940s. During this period Darwinism regained the attention of biologists through Neo-Darwinism, which sought to make the theory of heredity developed during the previous period compatible with Darwinism. Despite the name “a new synthesis” given to it by the most conspicuous Neo-Darwinist, Julian Huxley, I think this attempt to harmonize these two radically different ways of thinking is not a true synthesis that can account for both, but merely a contrived, eclectic combination.

Julian Sorell Huxley (1887-1975)

This conciliation between Darwin’s theory of natural selection of species and the chromosome theory of animal inheritance was started in the book by R.A. Fisher The Genetical Theory of Natural Selection (Oxford 1930), which advocated Darwinism with a new, additional assumption. Fisher’s opinion was accepted by an increasing number of notable biologists, including J.B.S. Haldane, C.D. Darlington, Sewall Wright, J.S. Huxley, T. Dobzhansky and E. Mayr, who made Neo-Darwinism the official truth of science.

What was Fisher’s positive contribution? Assuming biological evolution to be rigorously confirmed, Fisher felt the need to reconcile Darwinism with the chromosome theory of animal inheritance and showed that, as stated above, there is no incompatibility between this theory and the evolution of species by natural selection. At that time it was universally accepted that in the germ cell the characteristics of the animal that will result from it are preformed and that the characteristics acquired by an animal do not influence its sex cells. It therefore follows that chromosome theory must resort to natural selection as the only way to explain the extraordinary adaptation of each species to its particular form of life that has occurred throughout the ages.

Ronald Fisher (1890-1962)

Indeed, the Darwinists of the 1930s advocated the eclectic solution, still accepted by current biologists, that characters of the animal soma are somehow prefigured in the germ cell, in which they appear for the first time (and not in the animal in which they only project their effect), and from which the sexual cells are transmitted to successive generations. Consequently, geneticists considered the set of hereditary traits of the germ cell (the genome located in chromosomes), rather than the hereditary traits of the animals itself, to be the source of evolutionary variation of animals (by mutation of genes, translocation of genes, combinations of paternal and maternal genes, etc.) The variation thus postulated as occurring randomly and independently of the animal is wholly inconsistent with the exquisite adjustment that is clearly demonstrated by individuals of each of the 1 million species of animals and 300,000 plants, all perfectly adapted to living in their specific conditions. Fisher perceived this very weak side of the theory of genes and tried to reinforce it through natural selection. Since then, the dominant view among biologists is that the random alterations in the genome of the germ cells are the origin of change. Thus, mysteriously, the creative force of evolution lies in animal cells but the animal is given no more than a passive role in its own evolution: natural selection rejects individuals whose genome results in an imperfect phenome and conserves individuals whose genome results in a suitable phenome (individual). The Neo-Darwinists, trapped in the genetic theory of animal inheritance, state explicitly that natural selection (processes between animals and their environment) does not have the creative force, which lies in the genomes of germ cells, from which it emanates towards the animal. Animals (genuine individuals that we intuit to be so full of meaning) are thus incoherent with their process of origin; they are essentially incomprehensible, because it is postulated that they originate in something external to themselves and to their medium and the medium (whose active, creative role is ignored) passively filters the matter that the genome, the creator of varieties, presents to it and that is magically consistent with it.

Ernest Walter Mayr (1904-2005)

In short, I think that the Neo-Darwinists overcame the circumstantial obstacle that had led to the rejection of Darwinism, i.e. a hypothesis of Darwin unrelated to his theory (the hypothesis of gemmules) and somehow rescued evolutionist thought for biology. This was an important service. For two or three decades, the problems of animal and plant evolution posed in this way were very prominent. However, I am inclined to think that the Neo-Darwinists failed to overcome the second and main reason for the eclipse of Darwin in the period previous to them: specialization, the decadence of the prior integrating thought, and indeed, infidelity to the monist conception of science, according to which the universe is subjected to a consistent overall process of evolution in which everything (the animal, the human) is explicable in terms of everything else.

Consequently, in accordance with the dominant spirit of the 20th century, the eclectic attempt to reconcile the nascent genetics with the theory of natural selection subordinated Darwinism to the chromosome theory of inheritance. In other words, the great biological theory, capable of accounting for all previous science and obviously loaded with new and higher problems, was placed at the service of a new field of research specialized in discovering the formal correlations between certain data of the chromosomes of germ cells and certain characteristics of plants and animals (in the latter, never relating to the genuine animal individuality). In accordance with the spirit of the times, this field polarized many biologists towards specialized research, which served as an exclusive basis for a theory of inheritance that ignores the problems posed by taxonomy, phylogenetics and embryology and that is therefore unilateral, unsatisfactory and irrational. Indeed, despite its name, Neo-Darwinism sacrificed the integrative and evolutionist problems latent in classical Darwinism in favour of a theory that grasped a small partial truth whose meaning it failed to understand: a creationist theory, the chromosome theory of inheritance.

4. The period of gradual abandoning of Darwinism (1950 onwards)

In this artificial merger of two ways of thinking that were inconsistent with each other, the higher thought was subordinated to the lower thought. The consequences were not long in coming. The fourth period of the history of Darwinism stretched from the middle to the end of the 20th century. In this period, the theory of natural selection, which had once more been imposed by the Neo-Darwinists, has continued to be the official truth, but it has died in the most actively cultivated areas of biology: molecular genetics, biochemistry, biophysics, physiology, pathology and cytology. There are certainly biological areas (plant and animal paleontology and anthropology) in which Darwinism continues to be applied literally, and Darwin can be said to have been enshrined on the altars of science. However, it must be noted that Darwinism, or the theory of joint evolution of living beings, is outside the thought of most biologists, who do not even apply this theory to consider specific problems with strategic value for the progress of general biological thought or to interpret specific discoveries. Conversely, during this period scientists have ignored all possibility that specific discoveries could correct or extend the Darwinist theory of evolution and that this theory might be replaced by a truer and more general one that could account for the theory of Darwin as a particular case. Darwinism (like Marxism for Marxists in Economics) has come to be accepted as a dogma, as a rigid system that is assumed to be definitively established, whose formulas are used as a convenient argument whenever the occasion arises.

In short, I am inclined to think that in recent decades the exercise of biological research has fallen increasingly into specialization, with all its positive and negative features. The detailed analysis of the intimate aspects of living beings has progressed greatly, with the help of very subtle techniques of physics and chemistry that require a difficult and detailed interpretation of the data. However, this positive aspect has led to the fragmentation of knowledge, the polarization of biologists’ attention towards specific discoveries, neglect for their strategic significance for the progress of thought, and contempt for theoretical thought (in search of the law), which is precisely the leitmotif of science in pursuit of an increasingly consistent interpretation of the Universe. An ever-widening gap has thus opened between partial, specialized scientific theories and general thought, which had incorporated the major achievements of classical science as a guide to the action and experience of ordinary people. I am inclined to think that this gap and this fragmentation indicate not the depth but the error of specialized sciences.

To give an idea of the increasing gap that has recently opened between Darwinism and the most cultivated biological fields, we can continue with the example of genetics, in its new phase of molecular genetics, though the same could be said of many other areas of current biology. It seems clear that molecular genetics has lost interest in the problems posed by genetics in the first half of the 20th century (primarily, the correlation between genes arranged linearly in the chromosomes of germ cells and the hereditary traits of animals and plants) and now enthusiastically seeks the universal key to heredity in something even more hidden and smaller than the system of chromosomes carrying the genetic endowment of an animal or plant: nucleic acids, to which the property of self-multiplication is implicitly or explicitly attributed. If “self-reproduction” defines life, to understand nucleic acid would be to understand life ab ovo. In accordance with this transfer of the problem of heredity to the molecule, since the 1950s geneticists have also replaced the object that they investigate. Whereas previously they studied heredity in strains of plants and animals (much work was done on the Drosophila fly between 1920 and 1950), interest has shifted to the single-celled fungus Neurospora, the bacteria Escherichia coli and bacteriophages.

Theodosius Dobzhansky (1900-1975)

However, the two assumptions identified-that the capacity to self-replicate defines life and that nucleic acid is a self -reproducible molecule- are in my opinion erroneous for evolutionist thought. Indeed, without entering into a detailed analysis of the question, it should first be clearly established that in order to reproduce, the living being must first exist, so it must feed, i.e. apply energy to sustaining itself (to maintaining the focus of action and experience that it essentially is). Second, the first living being, with a totally incipient capacity for action and experience, must have been able to obtain energy (to feed) with great ease, and this can only be explained if it used the energy accumulated by the inorganic level from which this initial living being emerged as a unit of a higher level. Thus, the emergence of the first living being is integrated with its feeding. These two complementary sides of the same process require the co-evolution of the inorganic level, which was essential to the lowest living level, and this joint maturation process must have progressed to a considerable degree in an area of the Earth’s biosphere. All phylogenic, ontogenic and physiological data indicate unequivocally that this first process, from which the first level of living beings would emerge, took place in a mass of molecules charged with energy by the history of the earth, and within the primitive sea. Indeed, the first living being, whose paradigm is the current protein sustained by the control of molecules (the current metabolites), emerged from an association of molecules that used energy of intensely interacting molecules. However, the originary conditions in the biosphere could not have allowed a molecule to feed permanently on atoms and far less to reproduce itself. In particular, there were no objective conditions for a nucleic acid to grow and reproduce in a purely molecular environment by capturing energy from a suitable medium that was coherent with it (of course, it is meaningless to state that something is self-reproducing without a medium to feed it).

I therefore think that the key to heredity cannot lie within nucleic acid or even in the set of intracellular reactions that involve nucleic acid. This does not mean that the physical and chemical study of nucleic acids and their relationships with other components of the cell made by molecular geneticists and biochemists has not achieved an important series of discoveries, which are obviously linked to, and have strategic value for, heredity. However, I think that the theoretical advantage offered by this splendid crop of specific knowledge cannot be achieved through the narrow interpretation of a specialist.

Indeed, it seems obvious to me that what has been observed with so much effort and ingenuity in nucleic acids (the results of “molecular genetics”) can only take on meaning in the framework of the whole of which they form a tiny -though very significant- part: the protein and its medium and, above all, the cell and its medium. To this end, it seems critical that these data provided by physicists and chemists who are familiar with molecules and macromolecules should be considered by biologists familiar with the particular and genuine features of cells and animals. And if we are to raise the understanding of the living being to reach an understanding of its capacity to coordinate the molecules within it (discovered by biochemists and molecular geneticists), it is essential for biologists to understand what an animal essentially is. This leads to the consideration of its process of origin from cells (which existed before the animal; the animal emerged from cells and bases its animal individuality on them), which leads in turn to the consideration of the process of origin of the cell.

Indeed, 125 years after the publication of On the Origin of Species, everything obliges the biologist to address a new set of problems in the study of biological evolution, of which Darwinism is a key element. It therefore seems that biology does not require a return to the Neo-Darwinism of the second third of the century, increasingly subjected formally to dispersed specialized knowledge, but rather the development of a theory that can interpret the enormous wealth of knowledge in a truly integrating, evolutionist thought.

The updating of Darwinism

We have already seen that the wealth of knowledge that molecular genetics obtains from the physical and chemical examination of the interior of cells must be organized in light of general evolutionist thought, i.e. biological thought (dealing with living beings and not their molecules). What can seemingly be deduced from the historical examination of genetics can also be applied to other branches of biology that have been widely pursued in our time, such as biochemistry in general, and in particular enzymology, immunochemistry and cytology, in very specific studies of which the study of membrane phenomena is a good example. As with genetics, with regard to these and other disciplines that aim to unravel processes performed by living beings without considering living beings, but only their molecules, one can say the following: 1) due to the general coherence of all real processes, what is observed in the intimacy of the living being can contribute to knowledge of the living being; but 2) this knowledge, which would help to obtain a more coherent vision of reality, can only be obtained by viewing these partial process from a suitable perspective within the general process of living beings and the Earth’s biosphere.

To achieve this perspective, one must resort to Darwinism. Continuing with the example developed in the course of this foreword, i.e. examining the ups and downs of Darwinism with the help of its projection on genetics (an example that, undoubtedly, I have adopted because the genetics of the turn of the century was based on a general attack on Darwinism), I will try to specify the possible problems involved in a theory of heredity approached in evolutionist terms, i.e. based on the thought of Darwin but suitably updated and, above all, taking into account the great wealth of specific facts that have been discovered over the centuries. For the reader’s convenience, I will divide this brief presentation into a series of points, though they are all so interdependent that they are only complementary modes (all leading to each other), merely facets of a thought that is as integrating and evolutionist as possible. Its main principle could be that the Universe is subject to a single, coherent process of evolution, so the understanding of individuals requires the understanding of the whole and the history of this whole, and vice versa.

1.The first change that an updated Darwinism would have to make in genetics is to impose the ideas that there is no sole mode of heredity and that self-reproduction is the essential character of living beings

With regard to the first assertion, one must think, in fact, that if there are three levels of living beings (proteins, cells and animals), each characterized by a peculiar mode of action and experience (reflected in the corresponding type of medium) from which all manifestations (and therefore heredity) are derived, one must draw the conclusion that living beings of each level have a mode of reproduction that is qualitatively different from that of living beings of the other two levels. With regard to the second assertion, in addition to what has been stated above, if we bear in mind that reproduction is not the originary function of the living being (which is feeding, which secondarily caused growth, which in turn led to reproduction), it seems that we must conclude that the key to the heredity of the protein level cannot be found exclusively at the molecular level, setting aside the protein itself, and this is even truer of the heredity of the cell and animal levels.

Thus, if applied to Darwinist evolutionary genetics, the evolution of living beings and in particular their essential stratification in matter-energy levels (proteins, cells and animals) seems to indicate that one must distinguish clearly between processes of protein heredity, cell heredity and animal heredity, none of which (not even protein heredity) may lie exclusively in molecules, whatever their nature and complexity. Moreover, the boundary between the three processes of heredity may offer some difficulty because animal heredity, though completely different from cellular heredity, obviously involves the multiplication of cells and therefore must somehow integrate and govern processes of cellular heredity; and the same must happen between cellular heredity and protein heredity. Therefore, in the biological processes involved in the reproduction of the cell (in the various forms of cell division in the conjunction of two cells, in sexual reproduction, in chromatic reduction, etc.), we must distinguish between what corresponds to cellular heredity and what corresponds to the underlying protein heredity. And we must do the same in the processes involved in the reproduction of animals (the delimitation of sex sells and their encapsulation in gonads, the regulation of gonads, copulation, egg laying, fertilization, embryonic and foetal development, etc.), in which one must distinguish where animal inheritance ends and cellular inheritance starts. Another obvious problem of evolutionist genetics will be to distinguish how each two successive levels of heredity are coordinated and influence each other.

According to all the above, a genetics governed by Darwinist thought must abandon the false hope of a key discovery on the whole of heredity. It must especially avoid seeking it at the smallest level, pursuing it even in certain self-reproducing molecules. (Moreover, in my opinion, which is certainly not thoroughly matured, self-reproduction is objectively impossible at the molecular level and in the levels below it, so the molecules must be reproduced by the living beings of the lower-level). In genetics, as in other scientific fields, crucial discoveries only occur in function of the general progress of the theory. Outstanding changes sometimes occur in this progress when two sets of facts that had previously been interpreted separately are submitted to the same theory, or when a more general law that can encompass the previous law and its exceptions is discovered. If each of these theoretical conquests is correct, it gives scientific thought the possibility of discovering new specific facts that extend humans’ mastery of nature and in turn allow the theory to be contrasted, simplified and corrected. Thus thought, shaped by the coherence of the reality from which it stems, advances towards an increasingly unifying understanding of nature by incorporating the previous thought in increasingly deeper strata. This is done by partially negating the previous thought in order to account for it. In the healthy progress of science, there are no unexpected, magical discoveries: the discovery is always anticipated by the theory and affects the theory, and its importance is measured by its theoretical scope. In this regard we should recall Darwin’s exclamation at the age of 30, a couple of years after his journey around the world, when he formulated the thesis of natural selection as the main mechanism of evolution of species: “At last, I have a theory to work with”.

2. In each of the three mechanisms of heredity (which are different because they are of a different integrative level), it is important to distinguish the agent of the process from the artifact that uses the agent to perform the inheritance, and from the result in which the inheritance is materialized

For general evolutionist reasons that cannot be discussed here, I am strongly convinced that the agent of each of the three levels of heredity can only be the same individual that is reproduced; i.e., the only true agent of reproduction and protein heredity is the protein, that of cell reproduction and heredity is the cell, and that of animal reproduction and heredity is the animal.

In other words, heredity (like feeding, somatic coordination, movement, perception of stimuli, etc.) is a manifestation of the activity of a unitary being, of an individual, and it has the same basis as the others: it is action and experience coordinated at a given time by a state and with a special effect (reproduction). Thus, understanding biological inheritance requires knowing the biological individual in its essential activity, i.e. in its genuine action and experience. In turn, this requires understanding it 1) in terms of its soma, whose functional coordination is governed by that individual, and 2) in terms of the medium consistent with that individual, governed by somatic activity. Any correct theory of heredity must be placed within the wider framework of general biological theory. If we view the problem of heredity from this perspective, we will know that genetics is on the right road when the progress that it makes affects our essential knowledge of the living being and when general biological progress immediately provides a better understanding of heredity and reproduction. Indeed, we could say that, given the stratification of living beings, there can be no science of genetics but rather a chapter in the science of proteins dedicated to protein reproduction; a chapter in cytology dedicated to cell reproduction; and a chapter in the science of animals dedicated to animal reproduction.

3. The living being of any of the three levels is, in its intimacy, a genuine individual whose strict material substrate is a unitary physical field called an organism, which corresponds to idealistic notions of the psyche, soul, etc.

The scientific mode must be understood in terms of the other processes of reality. Now, in the radical unity of its organism (as opposed to the set of cooperating living beings of the lower level that form its soma), the living being is reduced to pure action, because the organism is annihilated as a result of each somatic event, and emerges from this event possessing the quantum of experience gained in it. This unity of action characteristic of a physical energy field that is annihilated moment by moment and re-emerges in the alternate moments (which is the focus of the action and experience that defines all living beings and allows them to govern their medium) is of course something very unstable; to maintain itself throughout the life of each individual, it must always be set against the general coherence of the reality from which it emerged and on which it operates, maintaining it and modifying it slightly. In short, the organism (where the individuality of each living being lies) is confronted, through the mediation of a soma (an organization of living beings of the immediately lower level), with the general coordination of reality that culminates in the medium, from which the living being obtains the energy that allows all its vital manifestations. In this way, the living being and all its modes of activity depend on and take account of the joint process of all reality as it occurs in the Earth’s biosphere in a word, in biological evolution. This may be a current conclusion of the evolutionist thought that Darwin started.

Let us see the implications of this evolutionist approach for our topic. All manifestations of the activity of a living being, including its reproduction and inheritance, can only be understood if they are placed in a proper perspective that connects them with the organism of the living being in question and the soma of the living being, through which it acts on the medium. In short, the nature and intensity of all the somatic activity and its effects on the soma itself are determined by these two opposite poles, which act on the soma: the unit (the organism) of the living being and the environment consistent with it (its medium). Needless to say, both poles (the organism and the medium) are subject to a process of ceaseless dynamism and, therefore, any manifestation of somatic activity and its artifacts, however rigid and stable, results from this dynamism and can only be explained by it. Thus, according to the evolutionist approach to the living being, stability results from directed change (evolution), and this change is governed at every point of the biosphere by the evolution of the living beings of the highest level that occupy the biosphere, and not the opposite, as creationist thinking tends to posit. It must be taken into account that the legacy of the fixed somatic structures that a level receives from the lower level (the animal from the cellular level, the cell from the protein level and the protein from the molecular level, in the latter case already governed by it) is the work of the action and experience of the lower level, and must be explained by this action and experience not in a teleological way but as useful results from their origin, which are of current value in each moment for the living being that produces this inheritance through its action and experience.

4. Needless to say, what a living being inherits from the immediately lower level -what, for example, an animal inherits from its zygote- is the process of development from which it will emerge

Moreover, from the moment when this development leads to the constitution of the filial living being (the animal offspring, from the moment when it acquires supracellular unity over the previous association of cells), it is confused with the somatic activity of the new being and is governed by the latter’s organism. We therefore cannot understand animal heredity without understanding the reproduction and ontogeny of the animal, and we cannot understand the animal reproduction and ontogeny without understanding animal action and experience, of which reproduction and ontogeny are only particular cases. Similarly, we cannot understand cellular inheritance without understanding cellular reproduction and ontogeny, and we cannot understand cellular reproduction and ontogeny without understanding cellular action and experience, i.e. the cell. Nor can we understand protein heredity without understanding protein reproduction and ontogeny, without understanding protein action and experience.

If we now consider the animal (as closer to our action and experience, because we are animals), I think that the only thing that can affect the foetal development performed by animal action and experience in the zygote and in the cells that stem from it (soon to be somatic cells) is the capacity for action and experience of each of these cells as unitary living beings (rather than anything inside them, necessarily incongruous with the animal, even if it determines this cellular capacity). This capacity for action and experience of their cells (their capacity to perceive and master their cellular media) is thus the genuine animal inheritance, what the animal receives from the immediately lower level. The animal cannot influence it radically and it therefore conditions what it is to be (as the cell and the animal are living beings of a different integrative level and therefore have qualitatively different modes of action and experience and media). However, the animal will influence the multiplication and differentiation of this set of cells throughout the foetal process, establishing for them (through regulation of the internal distribution of food) a suitable succession of ranges of internal media, which will determine -from the beginning of the foetal period until death- the acquisition of somatic characters as a result of the succession of stimuli that operate on the animal. Thus, from its origin every animal models itself, and its ontogenesis is confused with an active conquest of somatic characters (and at their respective levels, the same must happen in the cell and in the protein).

Certainly, these acquired characters are not inherited (the inheritance received by an animal is reduced to its own zygote and to the nourishing medium originally provided to it) and, accordingly, these characters do not influence the shaping of its descendants. However, they do intensely affect the probability that the descent will take place through the natural selection of the fittest individuals. Thus, the acquired characters do not influence the ontogeny of the next generation but they do actively and essentially affect the phylogeny (evolution) of the strains. This apparent paradox, which explains the extraordinary adaptation of species to their conditions of life, is therefore a rational conclusion of Darwin’s theory. Indeed (and the same should apply to the other two levels), in the evolution of animals, the source of progressive variation lies in the continuous refinement of the animal action and experience forced by the progress of its medium, and it certainly does not lie magically in the intimacy of the zygotes. Therefore, in the course of the evolution of a level, the same type of heredity is maintained but it is refined according to the complexification of the reproduction of the individuals (the ontogeny).

5. We must bring to a close this foreword in which we point out the need for, and possibility of, interpreting the great discoveries of contemporary genetics in an evolutionist way. I only wish to highlight two important points that are closely related and clearly posed by heredity at all levels

First, in the process of development of all living beings, in which their inheritance is driven by their action and experience, artifacts are produced at the service of the conservation of what has been acquired, i.e. at the service of stability. The subsequent activity based on these artifacts soon depends irreversibly on them; soon, as it were, it makes them the basic legacy of later development. This fact may give the false impression that these artifacts were made for heredity, in anticipation of it. The Darwinist study of heredity must discover the value of these artifacts of the action (which will later determine the heredity) for the moment in which they appeared (and therefore for the sustenance of the developing being).

Second, it is obvious that these artifacts support and establish the limits to the capacity for action of the realized being. Therefore, although the direct inheritance of an animal is its zygote as a living being, i.e. the zygote defined by its action and experience, this capacity is partly determined by the artifacts that are thus created by the zygote in its ontogeny and they therefore have a direct influence on the inheritance. In short, the legacy of the lower level determines the higher level, and from what we know it even seems likely that the cell’s action and experience model the artifacts of its own heredity (the instruments for fixing what has been acquired) by using the artifacts of protein heredity, raised by the cellular action and experience to a new order of processes in the course of the cell’s life.

Faustino Cordón.