Historically, Evolutionism consists of a complex of philosophic and scientific theories that maintain superior species, animal or vegetable, are derived from lower species.

Among the ancients Pythagoras, Xenophanes, Empedocles, and Herodotus appear to have conceived some type of evolutionistic idea. Modern authors claim to find some evolutionary passages in these ancient thinkers, but such a view is not admitted by all. It is probable that these early philosophers and thinkers knew the rhythmic alteration of earth, sea, and sky. Perhaps they even guessed the true nature of fossils.²⁰

It seems that the first evolutionist was Anaximander, who maintained that every living thing, including man, had its origin from fish. Aristotle supposed that fossils had their origin from mud, due to a rather imprecise "formative force." Other ancient authors, such as the Roman naturalist and historian Pliny the Elder (23-79 A.D.) held that fossils were a joke of nature (lusus naturae) by which shells and fish were carved into rock.²¹

Some Eastern Church Fathers, such as St. Basil and St. Gregory of Nyssa, appear to have a concept of evolution that approaches the modern view. They held that God had immersed into material such forces or potentiality to produce the various species of plants and animals when the ambient conditions were favorable.²²

Among the Western Church Fathers, St. Augustine held that God created animals in a form that was rudimentary or embryonic. God hid something virtual or potential in nature, to which St. Augustine assigned the term "producing principles" (rationes seminales), from which would originate all living things when circumstances were opportune.²³ However, this is not modern evolution, since development does not occur from inferior species but from the embryonic forms that lead individuals to be of the same species.

In the Middle Ages, the Arab doctor and naturalist Avicenna (about 1000 A.D.) returned to the formative power theory of Aristotle. He also thought that fossils were a joke of nature, just as Pliny the Elder. The contribution of Avicenna was a "plastic force" (vis plastica) which shaped living organisms, but was incapable of endowing them with life.²⁴

St. Thomas Aquinas was inclined to follow St. Augustine’s position on evolution. In the commentary on the Sentences of Peter Lombard, Aquinas said, "The opinion of Augustine is more reasonable than that of St. Gregory, and Augustine’s opinion defends the sacred scriptures better against the attack of the pagans...and his opinion pleases me more."²⁵

In the seventeenth century, many thinkers considered evolution. Among these was the Jesuit priest, Athanasius Kircher, professor in the Roman College, which would become the Pontifical Gregorian University. Kircher held that God created only a limited number of animal species. From this limited number, by means of the four types of causes noted by Aristotle and operating both intrinsically and extrinsically, came all the other species which actually populate the Earth. The position of Kircher corresponds to polyphyletic evolution, in which organisms arise from a number of evolutionary lines.²⁶

It seems that some Renaissance philosophers such as Giordano Bruno, Lucio Vanini, Francis Bacon, Descartes, Leibniz, Benedict de Maillet and others had some vague idea of evolutionary transformation. Lucio Vanini was censored by the Inquisition for his views in 1619. However, opposition to evolution was not just the view of churchmen. Early scientists also opposed evolution. Cuvier (1769-1831) explained extinction of living things by some cataclysm, and put emphasis on migration of animals. D’Orbigny, a disciple of Cuvier, maintained that there were successive creations for new species. The naturalists of the time did not care much, until Linnaeus (1707-1778) classified living things in his fundamental work, Systema Naturae. He maintained that God created each species and there are no new species.²⁷

Until the Renaissance, everyone commonly held the theory of Fixism. This theory of Fixism, or theory of Permanence, denies all mutation of species. Abiogenesis, or life from inorganic matter, had been a problem for Fixism, but was eventually solved by its rejection. Fossils had also been a problem for the theory. Exceptional thinkers, such as Leonardo da Vinci, Andrea Cesalpino, who was a philosopher, medical doctor, and botanist, and Girolamo Fracastoro, who was a scientist and author from Verona, all intuited the authentic nature of fossils.²⁸ However, the common opinion about fossils followed Pliny the Elder that fossils were a joke of nature, with the addition that the formation of fossils might have been influenced by the heavenly bodies. In fact, Charles Lyell (1830) determined that geological strata were not necessarily caused by violent cataclysms, but the product of natural laws. Thus the hypothesis of evolution from fossil plants and animals by generation was not accepted by Buffon, Bonnet, Robinet, Diderot, Goethe, or L. Oken.

The real founder of modern evolutionary theory was Le Monnet de Lamarck (1744-1829), who extended this evolutionary theory of descent to all species, with the exception of man.²⁹ Lamarck explained his theory of descent of all species by use and non-use of organs. By non-use organs became weaker. Consequently, the pattern of life of the weaker, or stronger, creature changed. Larmarck also invoked external changes to which living creatures, with stronger or weaker organs, had to adapt. Not all living creatures were transformed in the same way. Plants changed due to nutritional factors, while habits were also a factor for change in animals. Accordingly, functional modifications preceded morphological modifications. It is also notable that Lamarck admitted final causality, which Darwin did not. Lamarck’s views were forgotten in public opinion and replaced by the views of Charles Darwin.³⁰

Charles Darwin (1809-1882) explained and defended universal transformism in a materialistic form that excluded final causality. Darwin explained evolution by efficient causality.

The primary efficient causes of evolution, for Darwin, are cosmic and biological causes of variability. Darwin supposed indeterminate variability in organisms so that there is no limit in any part of a living thing by which it could become something else. In this way, transformation of species could continue without a break.³¹

The secondary efficient causes of evolution, for Darwin, are heredity, natural selection, and sexual selection. Darwin drew on ideas that were already current in his time. The struggle for life is also found in Hobbes, Adam Smith, and Malthus. This struggle for life allowed the variability in individuals to be able to produce progress in which the individual remains the same, but the more outstanding qualities obtained from variation are transmitted by heredity; for this reason the struggle for life is called natural selection. Natural selection was proposed by Darwin in 1859, but was already proposed by Spencer, who invented the term in 1852.

Darwin admitted some of the laws of his predecessors, although these were secondary to variability and natural selection.³² Darwin admitted Lamarck’s law of use and non-use of organs. He also admitted Cuvier’s law of mutual correlation, also called the law of intrinsic relation of mutual organs, which postulated that certain organs developed prior to others, for example, teeth came before the stomach. Darwin also admitted the law of compensation, or the law of economy, espoused by Etienne Geoffroy Saint-Hilaire and Goethe, which stated that one part of the organism is proportionally debilitated when the organic humors build up in another part of the organism.³³

Haeckel (1834-1919) was an important follower of Darwin. Haeckel pushed Darwin’s theory to the ultimate consequences. Darwin, in 1871, maintained that man also evolved. Haeckel, in 1866, anticipated Darwin in maintaining the evolution of man. Haeckel is also famous for his attempt to prove evolution from the Biogenetic Law of Geoffroy Saint-Hilaire, who stated that the individual embryo follows an observable pattern of growth that parallels the evolutionary development of its species, namely that ontogenesis reproduces phylogenesis. Such a theory is not in great favor today.³⁴

Neo-Darwinism, or the Synthetic Theory, is a important development of the ideas of Darwin. It was founded by Weismann, initially a follower of Darwin.³⁵ He denied the Lamarckian theory of use and non-use. He denied the role of heredity in evolution. He only affirmed natural selection, not only between individuals but between chromosomes of cell generation The Neo-Darwinians continue to be materialistic and against final causality.³⁶

Neo-Lamarckianism is among the modern theories of evolution. In France, this opinion is represented by Giard, Le Dantec, and Rabaud. Others who hold the this theory are Eimer, Cope, Kassovitz, Lotze, and Von Wettstein. The Neo-Lamarckians are against final causality, like the Darwinians. They retain the explanation of mechanistic mutation, heredity, and both natural and artificial selection.³⁷

The Theory of Punctuated Equilibrium (1972) was developed by Niles Eldrege and Stephen Jay Gould. They are Non-Darwinians. This theory of punctuated equilibrium is an idea that evolution, particularly the differentiation among species, occurs relatively quickly with longer periods of little or no change. This theory is still under discussion.³⁸ Pierre Perrier believes that this "jump model" followed by Non-Darwinians is applicable to macro-evolution, in that it jumps to "many" new forms of living things. The Darwinian position is adapted to micro-evolution, in that evolution continues "in a straight line."³⁹

Other modern evolutionists argue either from the lack of stability in the world, or from the stability of the world. I. Prigogine and I. Stengers argue in 1981 that wherever they look they find evolution, diversification and instability. On the other hand, Jacques Monod, writing in 1970, is a preserver of "periodical stability" so that evolution emerges paradoxically from a stable context, not by an intrinsic change of form but basically by chance.⁴⁰

Adversaries of Darwin included the Fixists and a number of Anti-Fixists.⁴¹ The Theory of Fixism, or the Theory of Permanence, rejects evolution and holds that species are created by God, and this opinion is held by Cuvier and Linneaus. On the other hand, the Anti-Fixists accept evolution but disagree with Darwin due to his monistic explanation of evolution, or because of Darwin’s rejection of final causality, or because of Darwin’s view that evolution is universal.⁴²

Evolutionists who are adversaries of Darwin due to his materialistic monistic explanation of evolution are Cuénot and Davenport, who hold that evolution is directed by God. Cuénot, nevertheless, holds with Darwin an exclusion of final cause.

Evolutionists who are adversaries of Darwin due to his rejection of final cause are the Psychobiologists. Von Hartmann holds an unconscious will. He is a Neo-Larmarckian Psychobiologist. He holds that all life (Law of Continuity) arises from inorganic material, and that inorganic matter is endowed with unconscious psychism. He also holds that evolution develops under the influence of organic intelligence (unconscious will) that is immanent in the living things themselves. Bergson and Le Roy hold a vital impulse. Von Hartmann and Bergson are theistic evolutionists.

Evolutionists who are adversaries of Darwin due to his rejection of the final cause include some who profess a final goal for "universal" evolution, such as Teilhard de Chardin, the Dominican priest Leroy, and Dorlodot. These "universal" evolutionists profess the need for a final cause and the need for some formal principle of being. They hold the soul is created by God. They hold evolution is directed by God. They maintain that there had to be special divine intervention for the appearance of the vegetative life of plants as diverse from the sensitive life of animals, which are specifically diverse. It is possible, they hold, that evolution might extend to the origin of the body of man.⁴³

Some other evolutionists profess a final goal for "restricted" evolution, such as De Sinety and L. Vialleton. Vialleton (died 1930) is the best of the "resticted" evolutionists. He is not a Fixist, but holds to some partial and non-mechanical evolution. For Vialleton, evolution is restricted to "formal species," that is, to the lower levels of taxonomy, such as species, genera and families, which differ by reason of external form or by quantity.⁴⁴ Further, he rejects monophyletic evolution, which holds that all living species arose from a single lower ancestor. The conclusions of Vialleton have been confirmed by Guyenot, even if Guyenot does not hold for final causality.