GOALS: An attempt was made to explore the philosophy of evolution in twentieth-century Neo-Scholastic literature, and to produce some theses for an academic class in philosophy.

PROBLEMS: Problems in the philosophy of evolution are unlike others in the philosophy of nature. For 150 years, evolution has been debated and continues to be debated. Other scientific hypotheses have been easily accepted. The Neo-Scholastics agree that the hypothesis of evolution has not been proved scientifically. Further, the philosopher quickly notes problems with definition, judgment, reasoning, and belief. Problems with DEFINITION arise due to lack of definition in some cases, or the use of vague popular definitions, or the use of a technical definition taken from some of the thirty different schools of evolution, or from the equivocal use of the term evolution as an universal law. Problems with JUDGEMENT that "evolution is true" arise from the thirty different types of evolutionary explanation, each with its own concept of "true" evolution. Problems with REASONING arise because evolution is more in the genus of history, not repeatable, and largely not observable, rather than in the genus of science which argues from observation, repeatable experiments, and mathematics. Problems with BELIEF arise due to the different methods of science, philosophy, and theology, each of which needs to be respected by the practitioners of other methods, to avoid ideology.

LITERATURE: The dissertation did an analysis of 120 Neo-Scholastic philosophers. Special reference was given to the sixteen twentieth-century Neo-Scholastic philosophers at the Gregorian University in Rome, which allowed sharper comparisons. The Neo-Scholastics early in the twentieth century rejected evolution on the basis of the principle of causality (every agent produces its like) and the principle of finality (the good of the new species is bad for the old species). Later Neo-Scholastics explained evolution by multiple lines of causality (for new species) and Providence (laws of nature). Pope Pius XII in Humani Generis (1950) allowed debate on the evolution of the human body. Evolution was taught at the Gregorian University in Rome (Maria Teresa LaVecchia. Evoluzione e FinalitB. Rome: Gregorian, 1999). 17 Neo-Scholastics affirmed evolution at an International Congress at the Pontifical Atheneum Regina Apostolorum in Rome in 2002 (Rafael Pascual, ed. L’Evoluzione. Rome: Studium, 2005).

METAPHYSICS: The synthetic part of the dissertation affirmed thirteen theses. Five of these theses were metaphysical and favored evolution. 1) Fixism was opposed in favor of the philosophical possibility of evolution. 2) The necessity of finality in the evolutionary process was defended. 3) Mechanicism, proposed by the Positivists, was rejected. 4) Materialism, affirmed by the Darwinians, was rejected. 5) Hylemorphism as an explanation of the substantial union of matter and form was defended. Matter is needed for the individuation of species. Form actuates the matter by eduction.

PHILOSOPHY OF MAN: Four theses were proposed in this area. 1) Against Darwin, the essential distinction between man and the other animals was defended. 2) The possibility of the evolution of the human body was affirmed. 3) The vital principle, or soul, of man was affirmed to be immediately created by God. 4) Finally, the (equivocal) evolutionary future of man was explored, which involves the primacy of cultural evolution, ethical considerations, immortality of the soul, and the possible restoration of the body.

UNIVERSAL LAW: Four theses tested Spenser’s idea that evolution is a universal law, and the application of evolution to the wider and non-biological fields was found to be equivocal (same word but different meaning). 1) Abiogenesis was affirmed to be possible, and perhaps probable, although equivocal. 2) Cosmic evolution was found to be possible, but equivocal. 3) Social evolution was improbable, and equivocal. 4) Evolutionary atheism was found to be impossible, and equivocal.

CONTRIBUTIONS: This is the first comprehensive study of the Neo-Scholastics concerning evolution. The study is geographically extensive, covering 120 Neo-Scholastics in Italy, Germany, France, Spain, Poland, Argentina, Mexico, and the United States. The study is philosophically extensive, covering metaphysics, philosophy of nature, philosophy of man, ethics, cosmology, and theodicy. The study is extensive in its treatment of all major philosophical aspects of evolution. A 17 page general index provided cross-references. A special second index lists 276 Thomistic references supporting the conclusions of the dissertation from 28 different writings of Thomas Aquinas. The latest published course notes (1999) used at the Gregorian University in Rome provided a continued reference, and the notes were also critiqued. An evaluation of the certitude of each thesis is also an original contribution. An extensive bibliography lists the core literature on the subject.