Recent developments in evolution and their implications for faith and theology
Author: Mariano Artigas
Published in: Scripta Theologica, 32 (2000), pp. 249-273.
Date of publication: 2000
The current state of evolutionary theories
The origin of the universe
The origin of life
The origin of the species
The origin of man
The evolutionary worldview
Divine action in the world
Evolutionism is undoubtedly the scientific theory that has provoked the most philosophical and theological debate in history. The bibliography on topic is vast, and it is impossible to summarise it in a short space. My attempt is more modest. In the first part I will briefly comment on the current state of evolutionary theories, and in the second part I will examine the relationship between these theories and Christianity.
When we talk about evolution we usually think of Darwin and his work The Origin of Species in 1859. But before Darwin there had already been attempts to explain evolution scientifically; of particular importance was that of Lamarck who, in 1809, proposed to explain evolution through the inheritance of acquired characters. In reality, evolutionary ideas are much older. Some 2,400 years ago, Aristotle referred to those who denied the existence of purpose in nature and proposed an explanation that is almost identical to the Darwinian one: the apparent purpose of the parts of the living organism would be explained by the fact that, among the different products of nature, only the best adapted ones would be preserved. Here is the argument as Aristotle puts it:
What prevents parts of nature from coming into being also by necessity, for example, that the incisor teeth become by necessity sharp and fit for cutting, and the molars flat and useful for chewing food, since they did not come into being thus for an end, but by coincidence? The same question can also be asked about the other parts in which there seems to be an end. Thus, when such parts turned out as if they had come into being for an end, only those survived which "by chance" were suitably constituted, while those which were not so constituted perished and continue to perish, like the calves with human faces of which Empedocles spoke* (1).
In the 19th century, due to Darwin's influence, evolutionism acquired its full importance. Darwin was first concerned with the origin of species, but later published another work on the origin of man and, incidentally, the origin of the first living creatures: these two subjects have since been the subject of much discussion at programs of study. In addition, evolutionary thinking has been extended to the origin of the universe and its subsequent evolution. By linking cosmic and biological evolution, one obtains a worldview that encompasses the entire history of the universe.
Then, in sections 1 to 4, I will address the current state of discussions on the origin of the universe, of life, of species, and of man. In section 5 I will examine the evolutionary worldview, and then, in sections 6 and 7, I will discuss its philosophical and theological implications.
I. THE CURRENT STATE OF EVOLUTIONARY THEORIES
I. The origin of the universe
Albert Einstein formulated general relativity in 1915 and applied it to the study of the universe as a whole in 1917. His theory proposed a changing universe; displeased with this idea, he introduced a "cosmological constant" into his formulas in order to obtain a static universe: he later said that this had been the worst mistake of his life. Willem de Sitter in 1916-1917 and Alfred Friedmann in 1922-1924 developed Einstein's theory in the framework of a dynamic universe, an idea that was corroborated when, in 1929, Edwin Hubble formulated the law that bears his name, according to which the universe is expanding and galaxies are moving away from each other with a velocity that is proportional to their distance from each other.
In 1927, Georges Lemaître proposed his theory of the "primeval atom", which, after being reformulated by Georges Gamow in 1948, is known as the big bang theory. According to this theory, some 15 billion years ago all the subject and energy in the universe, concentrated in conditions of enormous density and temperature, underwent an expansion which, followed by a successive decrease in temperature and local concentrations, produced radiation that should still be observed today. The detection of this fossil radiation in 1964 by Arno Penzias and Robert Wilson led to the general acceptance of the theory, which is also supported by their predictions of the relative abundance of light elements in the universe.
Like all physical theories, the big bang theory model contains problematic aspects. Since 1981, some of them have been solved by Alan Guth's "inflation theory" proposal , according to which the universe, in the first moments of its existence and during a very small time span, would have undergone an enormous expansion. In 1992, observations by the Cosmic Background Explorer (COBE) satellite of the background radiation revealed fluctuations in the early universe, which would explain the irregular distribution of the subject, necessary for the local condensations that gave rise to stars and planets.
The model of the big bang is generally in good health, but raises important questions. A 1994 article devoted to the current status concluded with the following words:
We don't know why there was a big explosion or what could have come before it. We don't know if our universe has relatives - other expanding regions far away. We do not understand why the fundamental constants of nature have the values they do. The big bang theory is supported by plenty of evidence: it explains the cosmic background radiation, the concentration of light elements and the Hubble expansion. It is therefore certain that any new cosmology will include the big bang model * (2).
Recently, new data obtained by studying the explosion of supernovae seems to show that the expansion of the universe, contrary to what was thought, is accelerating. Two remedies are proposed: one is to revise the theory of inflation, and the other is to admit that there is a repulsive energy subject which counteracts gravitational attraction: in this context, there is talk of introducing a "cosmological constant" reminiscent of that introduced by Einstein at the beginning of the 20th century * (3).
On the other hand, it seemed that, paradoxically, the universe might be younger than some of its components. New data has been obtained which seems to support the age of the universe as being about 12 billion years old. This difficulty has been overcome for the time being.
II. The origin of life
The age of the Earth is estimated to be about 4.5 billion years old. The oldest fossils date back to about 3.8 billion years ago. It is assumed that the earliest living organisms therefore appeared in the interval between these two dates.
There are several theories that attempt to explain the origin of life on Earth. One of the first was proposal by Alexander Oparin in 1922: life would have arisen in the water of the oceans. Oparin later expanded his explanations, which are related to coacervates, and stimulated the study of the origin of life. In a famous experiment in 1953 in Chicago, Stanley Miller simulated the conditions of the primitive atmosphere (ammonia, methane, hydrogen and water vapour, activated by electrical discharges) and obtained some amino acids, which are the building blocks of proteins; it seemed that the problem of the origin of life could be solved, at least in principle. However, the difficulties remain great. Life on Earth today is based on the mutual interaction between nucleic acids (DNA and RNA) and proteins; but nucleic acids are needed to make proteins, and vice versa. Moreover, these macromolecules are extremely complex, which makes it difficult to imagine that they originated spontaneously.
In the late 1960s, Carl R. Woese, Francis Crick and Leslie E. Orgel proposed what is now known as the "RNA world" theory, according to which primitive life was based on RNA*(4). This nucleic acid was supposed to possess two properties that it now lacks: it could self-replicate without the need for proteins, and it could catalyse protein synthesis. This hypothesis has been supported by data , such as the existence of ribozymes or enzymes made from RNA, but there are difficulties: it is not known how RNA replicated in the absence of proteins, and the highly complex training of RNA itself remains to be explained.
Other theories* (5) have been proposed. One of the most radical is that of A. Graham Cairns-Smith, who proposed that the first replicating system was inorganic and based on clay crystals*(6). Another proposal places the origin of life in deep-sea hydrothermal vents. However, the difficulties remain great; just think that the DNA of a bacterium, one of the simplest living organisms today, can have some two million nucleotides, on the organisation of which depends the DNA to be functional and able to direct the production of more than a thousand different proteins. In view of this, scientists such as Juan Oró, Fred Hoyle and Chandra Wickramansinghe have re-proposed the old idea of panspermia: life, or precursor compounds to life, would exist in other regions of space, and would have arrived on Earth, for example through meteorite collisions. In that case, it would remain unexplained how life has arisen in other parts of space.
Christian de Duve, award Nobel Prize winner for his work on the cell, believes that, given the characteristics of the physico-chemical world in which we live, the emergence of life through natural processes was inevitable.
The enigmas surrounding the origin of life are very large, despite the existence of different theories that have been proposed to explain it.
III. The origin of species
Darwin proposed in 1859 that natural selection, acting on heritable variations, is the main driver of evolution, but he knew nothing about the nature of these variations. From the work of Gregor Mendel, published in 1866 and rediscovered in 1900, Genetics became an essential part of evolutionary theory. The incorporation of Genetics into Darwinism led, around 1940, to the formulation of neo-Darwinism or the "synthetic theory" of evolution, which still considers natural selection to be the main explanatory factor in evolution.
A typical objection to neo-Darwinism is that it does not explain "macroevolution", i.e. the origin of new species or types of life. Darwinism insists on gradualism and claims that large changes are the result of the accumulation of many small changes, but alternative proposals have been put forward. The main one is the "punctuated equilibrium" theory, proposal by Stephen Jay Gould and Niles Eldredge, who argue that evolution is not gradual, but works in leaps and bounds: there would be large periods of stability interrupted by very short intervals in which large, abrupt evolutionary changes would take place. Gould and Eldredge claim that their theory is at agreement with the great discontinuities in the fossil record, in which no intermediate links are found. Neo-Darwinists, on the other hand, often say that the two views are compatible, so that punctuated equilibrium could be integrated into Darwinism: they say that geneticists, who formulated the synthetic theory, and palaeontologists who propose punctuated equilibrium, use two different time scales: changes that take place over thousands of generations appear sudden to the fossil record*(7). It is important to note that Gould and Eldredge's punctuated equilibrium proposes explanations that are not Darwinian but evolutionary: the discussion centres around the mechanisms of evolution, not its existence.
Another theory that disagrees with Darwinism is the "neutralism" of Motoo Kimura, who proposed his theory as early as 1967*(8). Kimura claims that most of the genetic mutations that provide the material for evolution have nothing to do with advantage or disadvantage, and that natural selection therefore does not occupy the central place attributed to it by Darwinists: evolutionary changes are due to the "drift Genetics" of genetic mutations that would be equivalent from the point of view of natural selection. Here again, Darwinists claim that neutralism fits within their theory, although there are differences of interpretation.
It is interesting to mention, in this context, the importance of "gene duplication", i.e. the existence of copies of the same gene. This makes the "released" genes available to undergo changes that may prove important in new future circumstances. It would then be understandable that there may be remarkable changes that do not require the gradual accumulation of small transformations.
One of the major difficulties of evolutionism is, in fact, the explanation of new types of organisation, which require multiple complex and coordinated changes. Current work on "self-organisation", such as that of Stuart Kaufmann*(9), is important in this respect. These are theories which, for the moment, are very hypothetical, which attempt to explain the origin of evolutionary transformations on the basis of natural tendencies that we still know very little about. Again, these works are sometimes presented as being opposed to Darwinism, but Darwinists claim that they fit within their theory and, in any case, are not criticisms of evolutionism, but attempts to provide deeper explanations of evolution.
IV. The origin of man
Since the publication of Darwin's theory, attention has focused primarily on the biological explanation of the origin of man. The search for intermediate links between man and other primates began, leading to the usual classification of the precursors of modern man: the African australopithecines (between 4.5 and 2 million years ago), followed by homo habilis (from 2.3 to 1.5 million years ago), homo erectus (homo ergaster is also mentioned, between 2 and 1 million years ago in Africa, and homo erectus in Asia), and the various varieties of homo sapiens. This is a field in which there are many uncertainties and frequently new developments that force us to change our outlook.
One of the major developments in recent decades has been the application of new methods of molecular biology in the programs of study evolutionary . Sometimes these methods lead to different conclusions from those derived from the study of fossils, and discrepancies arise between molecular biologists and palaeontologists. Thus, from agreement with molecular biology, the presumed common ancestor of chimpanzees and humans would be between 5 and 6 million years ago, much more recent than the previous estimate of around 20 million years ago. It is considered likely that the lineage of this common ancestor had already diverged from that of gorillas*(10).
In this field, the presumed determination of the origin of present-day man through the study of mitochondrial DNA, which is transmitted maternally, has had particular resonance. According to some molecular biologists, all present-day humans are descended from a woman who lived between 100,000 and 200,000 years ago in Africa and who has been given the significant title of "mitochondrial Eve", degree scroll . It should be noted, however, that the authors of these programs of study do not themselves claim to have scientifically proven monogenism*(11), and that their claims are not accepted by all: in particular, some palaeontologists have reservations, especially with regard to these molecular biologists' use of the so-called "molecular clock "* (12).
These discrepancies concern the presumed origin of present-day man. There are two different views: the model of "regional continuity" and the model of "recent African origin". The "regional continuity" model
argues that the very early species H. erectus (including H. ergaster) is merely an ancient variant of H. sapiens; it further argues that the last two million years of the history of our lineage saw a stream of interlocking populations of this species evolving in all regions of the Old World, each adapted to local conditions, but all firmly linked to each other by genetic exchange . The variability we see today among the major geographic populations would be, according to agreement with this model, the last permutation of such a long process*(13).
In contrast, the "recent African origin" model argues that, around 100,000 years ago, a new human being subject , originating in Africa, would have completely replaced the previous species:
The alternative model , which fits much better with what we know of the evolutionary process in general, proposes that all modern human populations are descended from the same ancestral population that arose between 150,000 and 100,000 years ago. The fossil record, though sparse, suggests that the place of origin was in Africa (although the Near East is another possibility). Proponents of this model appeal to the programs of study of comparative molecular biology to support the thesis that all modern humans are descended from an African population*(14).
The Y chromosome, which is inherited exclusively from the father, has also been programs of study and the results are agreement with model of recent African origin.
As for more recent times, it seems that, from about 30,000 years ago, only modern humans remained, although they coexisted for thousands of years with other ancestral human types (such as Neanderthal man). There is no unanimity about the origin of the different human groups that exist today.
Amidst much uncertainty, it is often claimed that today's humanity comes from relatively recent ancestors who appeared in Africa, or perhaps the Middle East, and spread across the Earth.
V. The evolutionary worldview
It is easy to see that, in each of the steps we have examined, there are many important questions. The model of the big bang is well established, but it cannot be considered as definitively established and contains many unresolved problems. There are very different hypotheses about the origin of life. With regard to the evolution of living organisms, although it is generally accepted that the combination of genetic variation and natural selection plays an important role, explanations are being sought that go beyond this outline. Finally, the origin of man is still shrouded in questions.
It may come as a surprise that, despite these uncertainties, which are numerous and serious, evolutionism as a whole is in good health. This is explained by the fact that evolution as a general fact is one thing, and concrete explanations of that fact (or, rather, of the many facts included in evolution as a whole) are another. The force of gravity exists, and it is the first of the natural forces that was successfully dealt with scientifically in Newton's mechanics; we know a lot about it, but its nature, after more than three centuries, remains as mysterious to us as it was to Newton. With respect to evolution, arguments drawn from various specialities seem to support the existence of a vast evolutionary process that has produced nature in its present state, although there are many questions and disagreements about its particular aspects.
Three major worldviews have predominated in Western thought. In antiquity, with various variants, an organicist worldview predominated, emphasising the hierarchy and finality of the different parts of the universe. The birth of modern experimental science in the 17th century led to the triumph of the mechanistic worldview, which is based on an analytical perspective, leaves no room for finality, and attempts to explain everything through the behaviour of the constituent parts. A major paradigm shift is now taking place. The new worldview that is emerging centres around self-organisation. It sees nature as the unfolding of a dynamism that produces different levels of structuring, so that the valid elements of the two previous worldviews are included in a new, deeper synthesis. In this worldview, theorphogenesis or training of new patterns occupies a prominent place, and also important is the concept of information, which is core topic in biology and can be applied in a similar way to other areas of nature. The idea of evolution occupies an important place in this worldview, which provides a unitary and coherent picture of the origin and development of nature.
II. PHILOSOPHICAL-THEOLOGICAL REFLECTIONS
Having outlined the present-day status of evolutionary theories from the point of view of science, I will now examine their relationship to Christianity.
Clearly, Christianity is not directly committed to any particular scientific explanation: scientific problems are of interest to it only insofar as they relate to its doctrine of salvation. The theological implications of evolution mainly concern two major questions: God's action in the world, and human uniqueness.
The Christian message on these issues has always been and remains the same. However, there are two reasons why its relationship to evolutionism should be analysed. The first is that evolutionism has long been used, and continues to be used today, as a weapon against Christianity, as if evolutionary theories make it unnecessary or even impossible to admit the existence of God, of divine world government, of a divine plan for mankind, and of the existence of spiritual dimensions in the human person; it is therefore important to show that there is no incompatibility between the scientific theories of evolution and Christianity. The second reason is that the examination of evolutionism can perhaps open up new perspectives that help to deepen the understanding of the divine action in the world and the nature of the human being.
I. God's action in the world
The evolutionary worldview admits two opposing interpretations, the naturalistic and the theistic.
According to naturalism, scientific progress shows that the universe is self-contained and needs nothing outside it: creation and, in general, divine action would be superfluous in a world that could be fully explained by natural forces as we know them through science. Nowadays everyone admits that science has limits, but naturalists claim that, although our knowledge is always partial and imperfect, scientific progress shows that there are no areas that escape the method of science: the scientific method first extended to the world of inorganic subject , then to the world of the living, and now extends to the world of man, so that nothing would remain outside its scope.
However, it can be shown that natural science transcends itself, since it contains assumptions and implications that go beyond naturalistic explanations. To be sure, science is autonomous at its own level and can progress without dealing with goal-scientific questions; but its existence rests on assumptions that are retro-justified, enlarged and refined by scientific progress, and the study of these assumptions, and of the feedback of scientific progress on them, is very consistent with the perspectives of metaphysics and theology*(15).
For example, scientific activity assumes that there is a natural order. Experimental science seeks to know that order, and any of its achievements is a particular manifestation of the natural order. It can be said graphically that the more science, the more order: the more science progresses, the better we know the order that exists in nature, although obviously we know it in our own way, through representations that are not always simple photographs of reality.
In fact, the progress of science today provides a knowledge in which the natural order acquires the modality of a self-organisation. When we reflect on this current worldview, which is permeated with subtlety and rationality, it is implausible to reduce nature to the result of the activity of blind and casual forces. It is much more logical to admit that the rationality of nature reflects the action of a God staff who has created it, imprinting on it tendencies that explain the prodigious capacity to form successive organisations, enormously complex and sophisticated, at different levels, until reaching the complexity necessary for human beings to exist.
I cannot resist commenting here on a kind of definition of nature proposal by Thomas Aquinas, which seems to me to be more complete and profound than the usual definitions. At the end of one of his commentaries on Aristotle's Physics, Thomas Aquinas goes much further than his master and writes:
Nature is nothing other than the plan of a certain art, namely a divine art, inscribed in things, by which those things move towards a certain end: as if one who builds a ship could give the pieces of wood that they could move by themselves to produce the shape of the ship*(16).
The comparison is much more topical now than it was in the 13th century: then it was no more than a simple comparison, whereas now it could be pure reality. Seen from a theistic perspective, nature loses nothing of what is proper to it; on the contrary, its dynamism and potentialities appear to be based on a radical foundation, which is none other than divine action, which explains its existence and its remarkable properties. All of nature appears as the unfolding of the divine wisdom and power that directs the course of events from agreement with its plans, not only respecting nature, but giving it being and making it possible for it to possess the characteristics that are proper to it. God is both transcendent to nature, because he is distinct from it and gives it being, and immanent to nature, because his action extends to all that nature is, to its innermost being.
This perspective sample that the alleged oppositions between evolution and divine action are groundless. Naturalism claims to evict God from the world in the name of science, but to do so it must close its eyes to the real dimensions of the scientific business . One can speak of an "integral naturalism" which, along the lines of the previous reflections, looks at natural science together with its assumptions and implications, the analysis of which leads to the doors of metaphysics and theology.
Many leading scientists admit that evolution and divine action are compatible. For example, Francisco J. Ayala, one of the leading representatives of neo-Darwinism today, has written that creation from nothing "is a notion which, by its very nature, is and always will be outside the realm of science" and that "other notions which are outside the realm of science are the existence of God and spirits, and any activity or process defined as strictly immaterial"* (17). Indeed, for something to be studied by the sciences, it must include dimensions Materials, which can be subjected to controllable experiments: and this is not the case with the spirit, nor with God, nor with the action of God. On the other hand, Ayala takes up the opinion of theologians according to whom "divine existence and creation are compatible with evolution and other natural processes. The solution lies in accepting the idea that God operates through intermediate causes: that a person is a divine creature is not incompatible with the notion that he was conceived in the mother's womb and that he is maintained and grows by means of food.... Evolution can also be considered as a natural process through which God brings living species into existence from agreement with his plan"* (18). Ayala adds that most Christian writers admit the theory of biological evolution, mentions that Pope Pius XII, in a famous 1950 document (the encyclical Humani generis), acknowledged that evolution is compatible with the Christian faith, and adds that Pope John Paul II, in a 1981 speech , has repeated the same idea.
Catholic doctrine affirms that everything depends on God, and that "creation has its own goodness and perfection, but it did not emerge fully finished from the hands of the Creator. It was created "in a state of progress" (in statu viae) towards an ultimate perfection still to be attained, to which God destined it. We call divine providence the dispositions by which God leads the work of creation towards this perfection. God guards and governs by his providence all that he has created, reaching powerfully from one end of the world to the other, and arranging everything with gentleness (Wis 8:1). For everything is naked and manifest in his sight (Heb 4, 13), even what the free action of creatures will produce (Vatican Council I: DS 3003) "* (19). In this perspective, God is spoken of as the First Cause of the being of all that exists, and of creatures as second causes whose existence and activity always presupposes divine action: "It is a truth inseparable from faith in God the Creator: God acts in the works of his creatures. He is the first cause who works in and through the second causes (...) This truth, far from diminishing the dignity of the creature, enhances it" * (20). It is not that God is simply the first among a series of causes of the same subject: his action is the foundation of the activity of creatures, which could not exist or act without the permanent influence of this divine action.
The existence of God and his action in nature would, according to naturalism, be unnecessary. Nature, including man, would be the result of blind forces. Darwinism is often used in this context to claim that Darwin has made it possible to be an atheist in an intellectually legitimate way, because Darwinism would show that it is not necessary to admit divine action to explain the order that exists in the world* (21). It is also said that Darwinism would make it possible to show that the hierarchy of ideas that places God at the top and interprets everything from God must be discarded: the Darwinian explanation would provide a kind of general algorithm that would explain, advantageously, what was previously claimed to be explained by recourse to divine action * (22).
These naturalistic doctrines often fall into a basic philosophical error: namely, they often assume that divine action and the action of natural causes are on the same level. If this is admitted, all natural actions will be interpreted as excluding divine action, and it will appear that scientific progress, which provides an ever broader knowledge of natural activity, increasingly puts metaphysics and theology on the ropes. Seen in this light core topic, evolution does indeed seem to make divine action unnecessary. However, these naturalistic reasonings forget that the scientific perspective, while not only legitimate but important, is only one perspective, which should not only not be opposed to the metaphysical and theological perspectives, but rather requires them, at least if a complete picture of the problems is to be obtained. As noted above, philosophical reflection on the assumptions and implications of scientific progress are fully consistent with the theistic perspective. On the other hand, the naturalistic perspective is necessarily incomplete, since it is content with the explanations of experimental science, as if human reason and experience could not go further, and Withdrawal to exercise metaphysical reasoning, which is one of the specific characteristics of human beings and is even decisive for scientific progress.
Naturalists have to face the obvious difficulty that, even if one accepts that natural forces are sufficient to produce the natural order we know, this order is so rational and specific that it requires, at least, the existence of a very specific physics and a very specific Chemistry that make the uniqueness of the biological order possible. It is noteworthy that, in the face of this objection, they merely state that, according to some physicists (who also hold naturalistic positions), it could be explained how the current natural laws have arisen from a primitive chaotic state, and in some cases they add that, after all, our world is possibly no more than one, our world is possibly just one among many, perhaps infinite worlds that would possess different characteristics, so that what seems unique to us is only because we happen to live in a world where the conditions necessary for life, and even rational life, exist. subject It would be trivial: it would seem logical that, if there are all possible worlds with their own laws, there is one, or perhaps many, where the conditions for life, even intelligent life, exist.
These explanations may have some truth to them. Indeed, nothing prevents the laws of our world from having originated from a chaotic primitive status , and that our world is just one among many. However, this does not test make naturalism correct, and leaves metaphysical and theological questions unanswered.
For example, our world may have begun as a fluctuation of the quantum vacuum, as some physicists postulate. But even in such a case, the metaphysical problem of the radical basis of its being remains. The metaphysical problem arises in the same way whatever the hypothetical original state of the universe, and even if one assumes that the universe had an unlimited duration in the past. Pope John Paul II, in a speech to the Pontifical Academy of Sciences, put it this way: "The Bible speaks to us of the origin of the universe and its constitution, not to provide us with a scientific treatise, but to clarify man's relationship with God and with the universe. The Sacred Scripture simply wants to declare that the world was created by God, and to teach this truth it expresses itself in the terms of the cosmology usual at the time of the writer. The sacred book also wants to communicate to men that the world was not created as the seat of the gods, as other cosmogonies and cosmologies taught, but that it was created in the service of man and for the glory of God. Any other teaching about the origin and constitution of the universe is alien to the intentions of the Bible, which is not intended to teach how heaven was made but how to get to heaven. Any scientific hypothesis about the origin of the world, such as that of a primitive atom from which the whole of the physical universe would be derived, leaves open the problem concerning the beginning of the universe. Science alone cannot resolve such a question: we need that human knowledge which rises above physics and astrophysics and which is called metaphysics; we need, above all, the knowledge which comes from the revelation of God" * (23).
God does not compete with nature. Approaches that set God and nature against each other are based on a metaphysical misunderstanding: they fail to realise that the existence and activity of second causes, instead of making the existence and activity of the First Cause unnecessary, are unintelligible and impossible without this radical foundation. Certainly, to think in terms of First Cause and second causes requires a metaphysical perspective that will hardly be adopted by those who think that experimental science exhausts the subject of questions and answers accessible to human beings. But, as trivial as this may seem, it should be remembered that any reflection on science, even when it is done to deny the legitimacy of a knowledge that surpasses it, presupposes accepting a certain dose of goal-scientific thinking.
On the other hand, one might think that the evolutionary worldview, rather than placing obstacles in the way of the existence of divine action, is quite congruent with the plans of a God who, because he so desires, ordinarily wants to rely on the action of created causes. Darwin himself, in the last paragraphs of On the Origin of Species, wrote:
Very eminent authors seem to be fully satisfied with the idea that each species has been independently created. agreement It seems to me to be more in keeping with what we know of the laws impressed on the subject by the Creator that the production and extinction of the past and present inhabitants of the world have been due to second causes, such as those which determine the birth and death of individuals* (24).
Too often, in discussing evolutionism, God and creatures are regarded as competing causes on the same level, ignoring the distinction between the First Cause, which is the cause of the whole being of all that exists, and the second created causes, which act upon and modify something pre-existing, needing the constant concurrence of the First Cause to exist and act at all times. In such a case, when this distinction is ignored, the dilemma arises: either God or natural causes. Then one has an impoverished idea of God, who becomes a undeus ex machina introduced to explain particular problems, especially the order or adjustment between various parts of nature. For example, David Papineau, in his review of Niles Eldredge's book Reinventing Darwin, published in the New York Times on 14 May 1995, wrote: "(Eldredge) makes it clear that he believes in no higher agent, and that natural selection is the only source of design (design) in nature* (25). It is easy to see that he opposes natural selection to a higher cause, as if we must choose one or the other, without noticing that created causality is compatible with divine action and even demands it as its ultimate foundation.
The problem should not be formulated as a kind of "skill" between God and evolution to explain natural purpose. Evolutionism comes to be seen as opposed to religion because scientific explanations would make divine action unnecessary. In fact, the efforts of naturalistic authors such as Jacques Monod, Richard Dawkins and Daniel Dennet are aimed at showing that the intelligent and provident action of God can be replaced by the sum of many small, purely natural steps through the gradual action of mutations and natural selection. It would be a mistake for the believer to accept this subject of approaches, which from entrance condition the answer that can be given and respond to an unfocused perspective: one then arrives at positions such as those defended by the "scientific creationists" in the United States, or by various authors who, on final, try to oppose the apparent anti-religious force of evolutionism by showing that the theories of evolution contain explanatory gaps. In this case, new variants of the "god of the holes" are proposed, which are always liable to be displaced by new advances in science and which, above all, respond to an unfocused approach, as if divine action were to fill in the gaps of natural causes in their own order, as it were mission statement . For example, Marie George alludes to this deficiency in her review of the interesting book Darwin's Black Box by Michael J. Behe* (26); the argumentation of that book is based on the existence of "irreducibly complex systems" which, being composed of well-adjusted parts that interact in the production of a functional effect, must necessarily be designed by an intelligence: but nothing prevents us from finding scientific explanations for the existence of these systems which, even in that case, would require the existence of a First Cause for their existence to be fully explained.
Today's scientific worldview is very consistent with the affirmation of the divine action that underlies all that exists. God is different from nature and transcends it completely, but, at the same time, as First Cause, He is immanent in nature, He is present wherever the creature exists and acts, making its existence and action possible. Moreover, God relies on second causes for the realisation of his plans, so that evolution is very consistent with this concerted action of God with creatures.
II. Human uniqueness
The above considerations take on special importance when applied to the human being. As is well known, the Magisterium of the Church has intervened to clarify this question. In 1950, in the encyclical Humani generis, Pope Pius XII declared that:
The Magisterium of the Church does not forbid that, according to the present state of human disciplines and of the Sacred Theology, the doctrine of "evolutionism", in so far as it seeks the origin of the human body from a pre-existing living subject , be investigated and discussed by experts in both fields - since the Catholic faith commands us to maintain that souls are created directly by God" * (27).
The Pope then added an appeal for objectivity and moderation because of the relationship of the doctrine of man to the sources of divine revelation, warning that the hypothetical character of evolutionary theories at that time should be taken into account.
In a 1985 speech , addressed to the participants in a symposium on Christian faith and evolution, Pope John Paul II recalled the text of Pius XII's teaching , stating that:
on the basis of these considerations of my predecessor, there are no obstacles between the theory of evolution and faith in creation, if they are correctly understood * (28).
It is clear that "right understanding" means admitting that the spiritual dimensions of the human person require a special intervention on the part of God, an immediate creation of the spiritual soul; but these are dimensions and action which, as a matter of principle, fall outside the direct object of natural science and do not contradict it in any way.
Taking into account the above-mentioned clarifications and referring again to the teaching of Pius XII, John Paul II taught in his catechesis, in 1986:
It can therefore be said that, from the point of view of the doctrine of faith, there is no difficulty in explaining the origin of man, as a body, by means of the hypothesis of evolutionism. It must be added, however, that the hypothesis proposes only a probability, not a scientific certainty. On the other hand, the doctrine of faith invariably affirms that the spiritual soul of man is created directly by God. That is to say, it is possible, according to the above hypothesis, that the human body, following the order impressed by the Creator on the energies of life, has been gradually prepared in the forms of antecedent living beings. But the human soul, on which man's humanity depends in final , being spiritual, cannot have emerged from the subject * (29).
In 1996, John Paul II addressed a message to the Pontifical Academy of Sciences, meeting in plenary assembly. He again alluded to Pius XII's teaching on evolutionism, saying that:
research Taking into account the state of scientific research at that time and also the requirements of theology, the encyclical Humani generis considered the doctrine of "evolutionism" as a serious hypothesis, worthy of a thorough study and reflection, as well as the opposite hypothesis* (30).
Shortly afterwards, he added some very interesting reflections, because they echo the progress of science in the field of evolution in recent times:
Today, almost half a century after the publication of the encyclical, new knowledge leads us to believe that the theory of evolution is more than a hypothesis. Indeed, it is B that this theory has gradually imposed itself on the minds of researchers, due to a series of discoveries made in various disciplines of knowledge. The convergence, in no way intended or provoked, of the results of work carried out independently of each other is in itself a significant argument in favour of this theory * (31).
These words should not be interpreted as an uncritical acceptance of any theory of evolution. Indeed, immediately following these words, John Paul II adds important reflections on the scope of evolutionary theories, their different variants, and the philosophies that may be implicit in them. Particularly interesting are the extensive reflections the Pope devotes to evolutionary ideas as applied to the human being. One could even say that this is the core of the Pope's document.
In fact, John Paul II says that the Magisterium of the Church is interested in evolution because the conception of man is at stake. He recalls that revelation teaches that man is created in the image and likeness of God; he alludes to the magnificent exhibition of this doctrine in the constitutionGaudium et Spes of the Second Vatican Council; and he comments on this doctrine, alluding to the fact that man is called to enter into a relationship of knowledge and love with God, a relationship that will be fully realised beyond time, in eternity. In this context, he literally recalls the words of Pius XII in the encyclical Humani generis, according to which the human spiritual soul is immediately created by God. And he draws the following consequence:
Consequently, theories of evolution which, according to the philosophies on which they are based, consider that the spirit arises from the forces of the living subject or that it is merely an epiphenomenon of this subject, are incompatible with the truth about man. On the other hand, such theories are incapable of establishing the dignity of the person * (32).
These reflections can be applied to "emergentist" doctrines which, while admitting that a higher plane than the material one exists in the human being, affirm that this plane simply "emerges" from the material or biological level. John Paul II affirms that we are faced, in the human being, with "a difference of ontological order, an ontological leap", and asks whether this ontological discontinuity does not contradict the physical continuity presupposed by evolution. His answer is that science and metaphysics use two different perspectives, and that the experience of the metaphysical level reveals the existence of dimensions that are situated on an ontologically higher level, such as self-consciousness, moral conscience, freedom, aesthetic experience and religious experience. Finally, he adds that to all this theology adds the ultimate meaning of human life according to the designs of the Creator* (33).
Of course, if by "emergence" we mean that in the course of evolution new traits have come into existence, then anyone who accepts evolution must consider himself an emergentist. However, emergentism is usually proposed as something else, namely, as a certain "theory of mind", or an explanation of the new traits possessed by human beings. agreement In any case, it is not difficult to agree with the agnostic Popper when he says that to speak of the emergence of the human mind means little more than placing a question mark at a certain place in human evolution. Sir John Eccles, who received the award Nobel for his work in neurophysiology and wrote a book on the human being at partnership with Karl Popper, repeatedly analysed the arguments for materialism, found them wanting, and concluded:
I am forced to attribute the uniqueness of the self or soul to a supernatural spiritual creation. To give the explanation in theological terms: each soul is a new divine creation.... This conclusion is of inestimable theological value. It considerably strengthens our belief in the human soul and in its miraculous origin by divine creation. There is not only a recognition of the transcendent God, the Creator of the cosmos... but also of the loving God to whom we owe our being* (34).
Although I do not share the interactionism proposed by Popper and Eccles, John Eccles' conclusion seems to me inevitable. A being staff like us requires a cause staff. It is also understandable that, since God's action extends to everything that exists, in our case the effect of divine action reaches a completely special level because it creates beings who possess the unique characteristics of personhood: principally, our peculiar mode of self-consciousness, the capacity to find and give meaning to our lives, the capacity to love and behave ethically, and the capacity to love God and to have a contact staff with Him. Of course, a detailed examination of these issues would take us far beyond the limits of my present argument. But it can be said that this perspective is quite consistent with scientific progress. Indeed, such progress assumes that human beings are able to represent the physical world as an object, that they possess the descriptive and argumentative capacities that make experimental science possible, and that they are able to set out to search for the values implied by scientific activity.
Scientific progress currently provides one of the best arguments in favour of human uniqueness, because it highlights the fact that we possess very specific capacities of knowledge : we can represent the world as an object, elaborate models that represent certain aspects of the world in the most convenient way, construct theories, devise experiments to put the consequences of these theories at test , evaluate the truth value of the knowledge thus obtained, apply this knowledge to the resolution of specific problems. All this sample that we are beings anchored in material nature and that, at the same time, we transcend it, possessing a self-conscious being staff capable of pursuing cognitive objectives that allow a controlled mastery of nature.
Accepting the special divine creation of each human soul does not mean that divine action contradicts the course of nature. That the existence of human beings must be related to a certain Degree of biological organisation is quite logical. The continuity of nature is compatible with the discontinuity implied by a specific divine action that produces a new level of being.
Some think it would not make sense to assert that there are special interventions of God to create human souls. But this is a problem that can easily be clarified. When such special interventions are affirmed, it does not mean that God changes. God does not act as creatures do. God continually intervenes in the course of nature, without changing Himself. Therefore, God's special intervention in creating the human soul does not mean that there is some sort of alteration in God's plans every time He creates a soul. God does not change, neither when He creates each human soul, nor when He sustains each creature in its being and activity. The newness is in the creatures, not in God. Of course, this newness is essential, because every human being belongs to nature but, at the same time, transcends it: there is, at the same time, continuity and discontinuity with nature.
Christian faith presents man as made in the image and likeness of God, and as the object of a special plan of divine providence. But it is sometimes claimed that the human being cannot be the goal of evolution, because the course of evolution includes many doses of chance, so that man is a contingent product of a process that might not have led to our existence* (35). It is easy to see, however, that for God, who is the First Cause of everything, there is no such thing as chance. Theology has always affirmed that God governs nature in such a way that not everything has the same necessity: the course of nature includes many contingent events which, however, do not fall outside God's plans. Once again, the distinction between the First Cause and the second causes is crucial; if it is lost sight of, it will be thought that, for something to be goal of evolution, it must happen in a completely necessary way, ruling out the contingency of chance: this seems to be the reasoning of those who deny that the evolution of life on Earth can respond to a divine plan aimed at the appearance of the human being. They think that, if man is the result of a divine plan, his production should respond to necessary scientific laws, which is incompatible with the randomness that pervades the evolutionary process. But chance, which is real because there are many confluences of independent causal lines, is totally controlled by God, who is the First Cause without whom nothing can exist.
An evolving universe seems very consistent with the idea that man is a co-creator who participates in God's plans and has the capacity to bring the natural and human realms into ever more evolved states. Of course, we are not creators in the same sense that God is the Creator who provides everything with the radical principle of being. Our causality is limited to created capacities that can only transform what already exists; we always need some pre-existing basis for our action. Moreover, the very possibility of our activity depends on God's will in each concrete case. However, we are truly creative. We have capacities that make it possible for us to participate actively in the goals God has set for himself in creation.
When speaking of evolution and the human being from a Christian perspective, it seems almost obligatory to mention the problem of monogenism, i.e. the origin of the human race from a first couple. In the encyclical Humani generis of 1950, after having established the freedom to discuss the possible origin of the human organism from other living organisms, Pope Pius XII wrote:
When it is a question of another conjecture, namely polygenism, then the children of the Church do not enjoy such freedom, for the Christian faithful cannot accept the opinion of those who affirm either that after Adam there existed on this earth real men who did not come from him, as the first father of all, by natural generation, or else that Adam means a certain multitude of ancestors, since it is not seen how such an opinion can be reconciled with what the sources of revealed truth and the teachings of the Magisterium of the Church propose concerning original sin, which proceeds from the sin truly committed by one Adam and which, transmitted to all by generation, is proper to each one* (36).
As is readily apparent from this text, the Magisterium of the Church does not claim to uphold monogenism for its own sake, and, in fact, has not made it the object of any explicit definition as a dogma of faith: it is generally admitted that Pius XII expressly avoided, in the text just quoted, closing the door to possible future developments. The Church is interested in monogenism only in so far as it is related to the sources of revelation, to the doctrine of original sin and redemption. In recent decades there have been various attempts by some theologians to interpret original sin and redemption in a way that is compatible with polygenism. It cannot be said that, so far, a truly satisfactory explanation has been achieved, but it cannot be completely excluded that one day it can be reached. On the other hand, for the time being it is very difficult to come to clear conclusions about monogenism or polygenism in science: although some authors sometimes claim polygenism to be scientifically true, such claims often contain debatable aspects. Moreover, while monogenism poses some difficulties to our quest to represent the origin of the human species, polygenism also poses non-trivial difficulties. And it should not be forgotten that there are known biological mechanisms that would explain, at least in principle, the monogenic origin of present-day man.
In conclusion, Christian reflection on evolutionism allows us to understand that evolution can be part of God's plan. If we place ourselves in an evolutionary perspective, evolution may contain many events which for us are random or chance but which, for God, fall within his plan. The evolutionary process presupposes the divine action that gives being to all that exists and makes its activity possible. The evolutionary origin of the human organism can enter into God's plans, because it presupposes a divine action that directs each step and is complemented by the special intervention of God who creates the spiritual soul in each new human being. The Church does not intend to intervene in the strictly scientific explanations of evolution, because this is not its purpose mission statement; what it intends to underline with its teachings is that everything in nature falls under divine action and, in a special way, that the human being is the object of the divine plan of creation and redemption. With its teaching, the Church provides the core topic to understand that a natural process that might seem blind and meaningless can in fact be part of a divine plan of love and salvation that gives meaning to the whole of human existence, including scientific activity.
- Aristotle, Physics, II, 8, 198 b 23-32 (edited by Guillermo R. de Echandía, Gredos, Madrid 1995, pp. 162-163).
- P. James E. Peebles, David N. Schramm, Edwin L. Turner and Richard G. Kron, "Evolution of the Universe",research and Science, No. 219, December 1994, p. 19.
- See the four articles presented under degree scroll: "report special: revolution in cosmology",research and science, no. 270, March 1999, pp. 7-37.
- Leslie E. Orgel, "Origin of Life on Earth",research and Science, no. 219, December 1994, pp. 46-53.
- Cf. John Horgan, "Evolving Trends. In the beginning...", research and science, no. 175, April 1991, pp. 80-90.
- A. G. Cairns-Smith, "The First Organisms",research and Science, no. 108, September 1985, pp. 54-67.
- G. Ledyard Stebbins and Francisco J. Ayala, "The Evolution of Darwinism", research y ciencia, nº 108, September 1985, p. 49.
- Motoo Kimura, "Neutralist Theory of Molecular Evolution", research and Science, no. 40, January 1980, pp. 46-55.
- Cf. Stuart A. Kauffman, The Origins of Order. Self-Organisation and Selection in Evolution, Oxford University Press, New York 1993.
- Meave Leakey and Alan Walker, "Ancient Hominid Fossils in Africa",research and Science, no. 251, August 1997, p. 75.
- Allan C. Wilson and Rebecca L. Cann, "Recent African Origin of Humans", Research and Science, No. 189, June 1992, pp. 8-13.
- Alan G. Thorne and Milford H. Wolpoff, "Multiregional Evolution of Humans",research and Science, No. 189, June 1992, pp. 14-20.
- Ian Tattersall. "From Africa - Once... and Again?", research and Science, no. 249, June 1997, p. 28.
- A systematic development of these ideas can be found in: Mariano Artigas, La mente del universo, Eunsa, Pamplona 1999.
- Thomas Aquinas, In octo libros Physicorum Aristotelis Expositio, Marietti, Torino-Roma 1965, book 2, chapter 8: lesson 14, n. 268.
- Francisco J. Ayala. La teoría de la evolución. De Darwin a los últimos avances de la Genetics, Ediciones Temas de Hoy, Madrid 1994, p. 147.
- Ibid., pp. 21-22.
- Catechism of the Catholic Church, n. 302.
- Ibid., n. 308.
- Cf. Richard Dawkins, The Blind Watchmaker, Labor, Barcelona 1988.
- Cf. Daniel Dennett, Darwin's dangerous idea, Penguin Books, London 1996.
- John Paul II, speech to the Pontifical Academy of Sciences, May the wisdom of humanity always accompany the scientific research , 3 October 1981: Insegnamenti, IV, 2 (1981), pp. 331-332.
- Charles Darwin, The Origin of Species, Oxford University Press, Oxford 1996, pp. 394-395: " Authors of the highest eminence seem to be fully satisfied with the view that each species has been independently created. To my mind it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes, like those determining the birth and death of the individual".
- "He makes it clear that he does not believe in any higher agency, and that common natural selection is the only source of design in nature".
- Cf. The Thomist, 62 (1998), pp. 493-497.
- Pius XII, Litt. enc. Humani generis, 12 August 1950, n. 29: AAS, 42 (1950), pp. 575-576.
- John Paul II, speech to scholars on "Christian faith and the theory of evolution", 20 April 1985: Insegnamenti, VIII, 1 (1985), pp. 1131-1132.
- John Paul II, General Audience, Man, the image of God, is a spiritual and bodily being, 16 April 1986: Insegnamenti, IX, 1 (1986), p. 1041.
- John Paul II, Message to the Pontifical Academy of Sciences, 22 October 1996, n. 4: in L'Osservatore Romano, edition in Spanish, 25 October 1996, p. 5.
- Ibid., n. 5.
- Cf. ibid., n.6.
- John C. Eccles, Evolution of the Brain: Creation of the Self (London and New York: Routledge, 1991), p. 237.
- Cf. along these lines: Stephen Jay Gould, "The Evolution of Life on Earth",research and Science, no. 219, December 1994, pp. 54-61.
- Pius XII, Litt. Enc. Humani generis, 12 August 1950, n. 30: AAS, 42 (1950), p. 576.