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Philosophy of Evolution: Hylemorphism

The Level of Certitude


The hylemorphic solution to the nature of evolution has a high level of certitude.

The purpose of this section of the dissertation is to assess the minimum level of certitude for the thesis proposed, with an additional comment of any suspected higher level of certitude. There are various levels of certitude that can be chosen. Opinion is defined as intellectual assent (or disagreement) given to one part of a contradiction with fear of the opposite.67 Possibility is defined as the capacity for existence for a concrete possible thing: internally, that its constituent characteristics are not impossible, and additionally externally possible, if there is power to produce the thing.68 Probability, also called likelihood, is defined as the weight of motives, or the accumulation of serious motives, for prudent assent to some proposition, which is intrinsic probability if the motive arises from the nature of the thing, and can be extrinsic probability if the motive is from authority, which can also suppose the internal motive.69

Summary of Probabilities is defined as an accumulation of probable arguments, considered according to their force, which results from a mere juxtaposition. Convergence of Probabilities is defined as an accumulation of probabilities which converge to produce a sufficient reason. Moral certitude is defined as firm assent to one part of a contradiction whose necessity arises from the moral law in the physical (not ethical) sense, e.g., every mother instinctively loves. Physical certitude is defined as firm assent to one part of a contradiction whose necessity arises from the very physical nature of the thing, e.g., the law of gravity. Metaphysical certitude is defined as firm assent to one part of a contradiction whose necessity arises from metaphysical necessity, e.g., my own existence.70

Certitude could arise from some observable fact or experiment. However, there is no experiment to prove evolution.71 Some restricted observation of evolution is possible within species.72 Aristotle assumed the fact of change and motion from observation.73 "We must take for granted," he says, "that things of nature, either all or some, are in motion. This, as a matter of fact, is clearly evident by induction" (Aristotle Physics 1. 2. 185 a 12-14).74 Donat notes, relative to Hylemorphism, that Scholastic philosophy of nature can learn a lot "from experience."75

Certitude could arise from some philosophical explanation that exists. Hylemorphism is demonstrated in the observation of substantial change. Substantial change is a change that reaches even to the substantial being (esse) of the body.76 Such a substantial change in material bodies needs two elements, namely some true physical reality which is indeterminate in the genus of substance (called prime matter), for otherwise there would be change without a subject. The act corresponding and determining prime matter to this or that species of corporeal substance, is called substantial form. Therefore, if there is substantial change in bodies, it is necessary to conclude that corporeal bodies consist of two elements, both in the genus of substance, with one as potency and the other as act.77

Certitude could arise if the argumentation was based on some philosophical principles. The principle of causality and the principle of sufficient reason were employed to show Evolutionism is compatible with Hylemorphism.

Certitude could arise if the explanation is sufficient, due to the principle of sufficient reason. Hylemorphism has been shown to be more than adequate for an explanation of substantial change, but the change from one species to another in evolution is a substantial change. Therefore, Hylemorphism provides a more than adequate ("necesse est") sufficient reason for substantial evolutionary change.78 Further, Hylemorphism not only explains the substantial change of inorganic to organic by nutrition, but explains the opposite substantial change of organic to inorganic by death.79

Certitude could arise if the explanation was rooted in St. Thomas Aquinas, thereby being faithful to tradition. The problem was not confronted directly or explicitly by St. Thomas.80 However, the solution lies in the Aristotelian doctrine of Hylemorphism which St. Thomas did endorse and explain: "Even in spiritual substances, or angels, there is a composition of act and potency (only God is pure act). In fact, when two elements are found in a thing, of which one complements the other, the relation of one to another is like the relationship of potency to act. Now, in a created intellectual substance are found two elements, that is essence (substantia) and existence, which is not the essence itself: existence is the complement of the existing essence, because each being is in act in so far as it has existence. It remains therefore that in every so-called substance there is a composition of act and potency" (Aquinas Summa Contra Gentiles 2. 53).81

Certitude could arise if Neo-Scholastics agree on the possibility of Hylemorphism. Agreement is had by Neo-Scholastics in genreral.82 Among these Neo-Scholastics are the following: Brother Benignus,83 Klubertanz,84 Dezza,85 Gardeil,86 Hellin,87 Marquart,88 Maritain,89 Masi,90 Mondin,91 Palmes,92 Possenti,93 and Renard.94 In addition, Hugon lists the Neo-Scholastics who adhere to Hylemorphism as Sanseverino, Liberatore, Zigliara, Cornoldi, Pesch, Pope Pius IX, Pope Leo XIII, Farges, De Vorges, Mielle, Nys, and others.95

Certitude could arise due to recent scientific confirmation by convergent scientific arguments. Calcagno notes, with references to fellow professors at the Gregorian University, that celestial bodies are composed of the same elements as terrestrial bodies, and since those elements are transmutable among themselves, it can be generally concluded that all natural bodies consist of prime matter and substantial form.96 Hoenen, of the Gregorian University, had to correct St. Thomas about the identity of celestial and terrestrial bodies. St. Thomas believed that "the material of the celestial body is not the same as the (terrestrial) elements" (Aquinas Summa Theologiae 1. 66. 2. corpus et ad 4; Aquinas De Caelo 1. 6; confer: Aquinas Scriptum in Liber Sententiarum 2. 12. 1. 1).97 Modern science ("hodie patet") has shown that celestial and terrestrial matter are alike, therefore supporting Hylemorphism. Science has already turned from the Positivistic, Materiaistic, and Mechanistic point of view toward a fuller explanation of types of Vitalism.98

Certitude could arise if the opinions opposed to Hylemorphism are not tenable. But the opposite Mechanicist (Atomist)99 and Dynamicist (Moderate Mechanism)100 theories are not tenable.101 Plames also shows that Hylozoism102 and Pantheism103 are not tenable.

Certitude could arise if the objections of adversaries are able to be answered. Objections against Hylemorphism can be answered.104

OBJECTION: Your argument for Hylemorphism is not general; at most it is valid for living bodies and for non-living bodies assimilated by nutrition. But not all chemical elements are assimilated by nutrition. Therefore, the argument does not cover these inorganic elements. REPLY: The assertion is denied. The conclusion of the argument extends to all inorganic bodies, by way of analogy. Inorganic bodies that substantially change to living bodies are not of the different genus as those which are assimilated. Therefore, these bodies must also be composed of material and form.105

OBJECTION: Assimilation of inorganic elements by organic in nutrition is not substantial change, because the inorganic is subject to the influx and direction of the organic body. REPLY: The assertion is denied. If the subordination of the inorganic elements was not substantial change, the inorganic would not be substantially changed into the living body. Accordingly, the living body would not be an essential (per se) unity, but would be composed of many diverse substances only in an accidental union.106

Certitude can be had from the possibility of philosophers and theologians admitting this mode of origin without damage to their other beliefs. St. Augustine notes that prime matter and substantial form do explain substantial change (Augustine Confessions 12. 6-7).107 Philosophers like Palmes use the theory of Hylemorphism to explain the rational soul.108 Donat says Hylemorphism is a certain in application both in philosophy and theology.109

Certitude can be had from the fact the Hylemorphism is the best answer now to explain process of evolution.110 St. Thomas makes a distinction between a "verified" universal (dici de omni) and a "provisional" universal (ut nunc).111 This provisional universal, within a working hypothesis, is very useful in the investigation of nature. An example of a verified universal (dici de omni) is that in a right triangle every right angle has ninety degrees. An example of a provisional universal (ut nunc) is "white" predicated as a common property of swans, or evolution predicated as the common property of every origin of species. The example of the right triangle is a property based on certain (propter quid) demonstration. The example of the white swans is based on an incomplete (quo) induction, since the reporters had never seen a black swan. There is some difference of opinion among Neo-Scholastics about the ulterior determinations of material, form and the composit. Hellin notes that Aristotle founded his Hylemorphism on the view that there cannot be a discontinuity of atoms, while most Neo-Scholastics hold a type of Hylemorphism which admits the theory of discontinuity and Scientific Atomism.112 Nevertheless, this is more a problem in application,113 since every Neo-Scholastic uses the elements of Hylemorphism. Further, even those reluctant to ascribe absolute certitude to Helylomorphism, like Lepidi just cited by Hellin, note that Hylemorphism is "more true," "more reasonable," and a "safer"as a point of view. Thus, the compatibility of Hylemorphism with Evolutionism is the best current explanation of evolution.

The level of certitude for "Evolutionism is compatible with Hylemorphism" is at minimum at the level of the metaphysically certain. The proof is the principle of causality and sufficient reason. Further, the convergence of all of the above arguments are proof, especially the fulfillment of the principle of sufficient reason. This agrees with the opinion of Calcagno.114 Mondin thinks that Hylemorphism "is the greatest discovery of the philosophic and metaphysical genius of Aristotle, and it is a discovery that has perennial value."115 Donat says Hylemorphism is "certain."116

Having come to the correct conclusion on the philosophical level of certitude, the philosopher must still conclude with some humility. The philosophy of nature does not disregard the objects observed and perceived by sense.117 This is the method of Aristotle and St. Thomas.118 This method is confirmed by the Neo-Scholastic Jacques Maritain: "It is the upward resolution toward intelligible (as compared with the sensible) being... In this process the sensible object is not lost sight of..."119 Hylemorphism itself must be proved by rational argument. Yet it is the material that is very important because it is the principle of individuation, as St. Thomas holds: "It must be said that those things which differ in number in the genus of substance, not only differ accidentally, but also in form and in material. But if it is asked whence these forms differ from one another, there is no other reason except because the difference is in the signate material. Nor is there found another reason why ‘this’ material is divided from ‘that’ material, unless because of quantity. Therefore material subject to dimensions is understood to be the principle of this diversity" (Aquinas De Trinitate 4. 2. ad 4).120 While it is the material that is important, it is the cause of problems in several ways. First, there is a tendency to confuse the role of material, because "A mistake commonly made is to ‘imagine’ formal and material cause in terms of efficient cause...whereas no sensible experience can bring a realization of material and formal causality."121 Second, although material is familiar, its change may not be, so, "One difficulty that troubles the moderns did not worry Aristotle, the practical recognition of substantial change."122 Third, the role of the material perceived can be more deterministic or dynamic, both of which can be maintained in an extreme way, so that "it is part of its (philosophy’s) task to root out the double illusion of Mechanicism and Vitalism (of Driesch)."123 Fourth, philosophically speaking, the difference between biology and physics in this matter of certitude is due to the difference in necessity and contingence between living things and non-living things, because although "inanimate (non-living) things have activities that are contingent only with respect to the First Cause; living things have activities that are contingent even with respect to secondary causes (that is, their effects can be impeded by unfavorable conditions, or by defects in their own matter, as in sterility).124 Fifth, prime matter is not able to be known in itself, because something is able to be to be known in so far as it is in act, for intelligibility if founded on being; and being is only properly predicated about something that actually exists.125

Author:  John Edward Mulvihill, S.T.D., D.Min., Ph.D.
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