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Theory of Evolution

Philosophy of Science


The Philosophy of Science judges the logic and validity of hypotheses.
The State of the Question:  Are individuals of the same species immediately created by God, or do species arise by slow variation?
Philosophic definition of "species":  the same nature or essence found multiplied in many individuals.
Taxonomic definition of "species":  collection of individuals which has some characters in common clearly distinct from the characters of others; or Mayr:  "biological species is an ensemble of local populations that are knit together by gene flow."  (Bunnin 2003, 334)

Arguments that favor evolution arise from 1) palaeontology (sequential fossils), 2) biogeography (greater differences the longer continents are apart), 3) comparative anatomy (hand bones in man and ape), 4) embryology (embryo transits primitive forms), 5) rudimentary organs (vestigial wisdom teeth), 6) breeding (better plants or faster pigeons).  (Boyer 1933, 187)
Arguments against evolution of species:
1. " Nature" ("being" tending to its final goal) is ordered to perfection, not destruction.
2.  The "effect" cannot be greater than the "cause".   Aquinas says an agent produces its like (S.Th.  I, q. 91, a. 2) and like produces its like (I, q. 65, a.4).
3.  Induction of facts on intimate organization of creatures support only limited evolution of Variety (terrier), Species (domestic), Genius (dog), Family (doglike), and do not support evolution of Order (carnivore), Class (mammal), Branch (vertebrate), or Kingdom (animal).
4.  There are not contrary arguments, since only limited evolution is proved by palaeontology, biogeography, comparative anatomy, embriology, or rudimentary organs.  (Boyer 1933, 192-193) 
Conclusion:  Evolution between philosophical species has not been proved.  Evolution is possible in the lower grades of taxonomy of plants and animals.  Arguments are from 1) accidental (not substantial) changes in Variety, Species, Genus, Family, but not Order, Class,  Branch, or Kingdom;  2) and from some facts (palaeontology's fossils and biogeography's horse).  (Boyer 1933, 191) (Bunnin 2003, 336)

Darwin holds that the whole man (soul and body) evolved. (Boyer 1933, 180) 
Thesis: Evolution cannot account for the soul or active principle of man.  (Boyer 1933, 180-183)
1.  Soul is not generated from matter, since act does not come from potency; and the soul is intrinsically independent of matter in its operations (negative numbers, concept of zero, heroism) and operation follows essence (agere sequitur esse).
2.  Parents cannot give the soul, since each would give a part, and the soul has no parts.
3.  The soul does not pre-exist as an idividual since it is matter that individuates.
4.  The soul needs the body for perfect cognition, so pre-existence would be imperfect. 
5.  From ethics, the merit of the pre-exiting soul either lasts (but no memory, so no sanction) or does not last (so no sanction).
Thesis:  Evolution cannot account for the body or the material principle of man. (Boyer 1933, 194-195)
1.  Man is a philosophical species distinct not just by quantity but by distinct organization.  Parents of humans give material apt to receive the form (soul).  God, although all-powerful,  normally uses natural causes (apt material) and builds on nature. 
2.  Arguments for the evolution of man are weak.  Fossil record does not show a series, and so has no ontological force.
Evolution is not only philosophically untenable, but erodes theological values such as 1) the unity of mankind, and 2) the dignity of woman.  (Boyer 1933, 197)

What explains the popularity of the theory of Darwin from the publication of Origin of Species down through the 20th century?  First, the explanation is simple, mechanistic, and can easily be understood by all.  Secondly, there is a confusion between philosophic species and taxonomic species.  (Boyer 1933, 197)

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