From Garrigou-Lagrange's The Trinity and God the creator, Ch.37.
Transformism and the Origin of Life
State of the question. The question of the origin of life and of the different species of living things is one of the most important of those that pertain to the creation of corporeal things. The modern theory of transformism was scarcely mentioned among the ancient philosophers, although St. Thomas sometimes spoke of the hypothesis of the appearance of new species. This problem is in some way connected with the old question of universals: whether the universals are fundamentally in individual beings according to their unchangeable nature.
Transformism may be either absolute or moderate.
Absolute transformism holds that matter is uncaused, that it exists of itself from eternity, and that from it by successive transformations have issued different living beings, that is, vegetative, sensitive, and intellectual life. (Huxley and Darwin.)
Moderate transformism holds that matter is not uncaused but is created by God, that it is not eternal, that the first living beings were created by God, and that God intervened in a special way to produce sensitive life, in the formation of the human body and in the creation of the spiritual soul. This moderate transformism refers to the production of various species of plants and animals which derive by successive transformations from the first living beings. Some of those who hold a moderate transformism think that all plants and animals come from different species created by God; others think that all plants came from one species and all animals came from one species of animal. Those who support the theory of transformism are not agreed on the definition of species; what one calls species another may call a variation.
Absolute transformism. This theory manifestly contradicts faith and reason inasmuch as it denies all intervention by God. It is directly opposed to the dogma of creation ("In the beginning God created heaven and earth"), since it teaches that matter has no cause and is eternal. This theory is opposed to all the proofs for the existence of God, and it implies that more is produced by less, the more perfect by the imperfect. This is at the same time against the principle of contradiction or identity, against the principle of the reason of being, the principle of efficient causality, and the principle of finality. It implies an ascending evolution, in which something more perfect appears without any reason, without any efficient cause, without an end, and without order. This theory destroys all intelligibility of things, as we have explained at length on another occasion. Such an evolution of species would be entirely fortuitous, without any preconceived idea or finality, and no reason is supplied for the wonderful subordination and coordination of things in nature.
In even the most ancient species, as we know from fossils, the organs are adapted to an end, coordinated with one another, and subordinated to the preservation of the individual and the species. All this cannot be attributed to chance; it presupposes an intelligent cause. Chance is a cause , a cause that is accidentally connected with a cause , and therefore an accidental cause cannot be the first cause of the order in things, for then order would come from the privation of order, and intelligibility would come from unintelligibility. What would be more absurd than to say that the intellects of the great doctors and the charity of the saints derived from a blind and material fate? The greater cannot be produced by the lesser. Hence absolute transformism substitutes the most patent absurdity for the mystery of creation.
This refutation of absolute transformism is confirmed by experience, which shows that every living thing comes from another living being and that there is no spontaneous generation. Pasteur and Tyndall demonstrated that no living beings are generated where all ova and seed have been destroyed. Such bacteria as are said to be generated in the atmosphere do not come from inanimate matter but from ova existing in the atmosphere. Huxley himself admitted Pasteur's conclusions.
St. Thomas held that certain animal life was generated by putrefaction under the influence of the sun. His explanation was as follows: "A heavenly body, since it is a moving thing that is moved, has the nature of an instrument which acts with the power of the principal agent; and therefore it can cause life by virtue of its mover, which is a living substance." St. Thomas never admitted that the more perfect being can be produced by the less perfect.
Moderate transformism. This theory does not oppose the teaching of faith. The words of Genesis ("And God said: Let the earth bring forth the green herb, and such as may seed, and the fruit tree yielding fruit after its kind") show that there was some difference among the species that God created, but they do not assert that all species were immediately created by God. St. Thomas himself said: "If certain new species should appear, these have existed previously in certain active forces; in this way what is generated by animal putrefaction is produced by the power of the stars and the elements," that is, "by the power of the mover (of the stars), which is a living substance." Thus St. Thomas maintains inviolate the principle of causality, according to which the more perfect cannot be produced by a less perfect being as a fully sufficient cause.
Lastly, it is difficult to say where true variation begins and where species leaves off in the ontological sense. Generally interfecundation is held to be the sign of membership in the same species. If it is pointed out that the horse and the ass generate the mule, it should be remembered that the mule is sterile, that is, it does not propagate a species. Here we have confirmation of the principle that operation follows being, and the mode of operation follows the mode of being; from this it follows that every animal generates offspring similar to itself in species. Ontological species therefore are immutable. But it is difficult to say when two animals belong to the same species properly so called or to two similar species. We do not have a clear enough understanding of the specific difference between living sensible beings; their specific forms are deeply immersed in matter and hardly intelligible to us. We know them only in a descriptive manner, empirically.
But when we come to man, we clearly understand his specific difference because it is not immersed in matter. Man's reason or rationality is a form of intellectuality, and intelligence is distinctly intelligible to itself because it is essentially ordered to the cognition of intelligible being itself and the reasons for the being of things.
It is clear, then, that the human soul cannot be educed from the potency of matter; on the other hand the specific form of plants and animals is educed from matter by way of generation.
1261 Summa Theol., Ia, q. 73, a. 1 ad 3; q. 115, a. 2. "Whether there are any seminal reasons in corporeal matter."
1262 Garrigou-Lagrange, De revelatione I, 233-76.
1263 Summa Theol., Ia, q. 70, a. 3 ad 3.
1264 Ibid., q. 73, a. 1 ad 3; q. 115, a. 2
1265 cf. Dict. apol., art. "Transformism."
1266 Summa Theol., Ia, q. 118, a. 1, 2.
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