Philosophy of Evolution: Hylemorphism

Participants in Dialogue


Hylemorphism is an Aristotelian philosophical position.
The history of Hylemorphism began with Aristotle (384-322 B.C.), who studied natural being with a search for its ultimate principles.8 He began his search by determining the intrinsic principles of natural being.9 Aristotle assumed the fact of change and motion. "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).10 With the acceptance of change or movement goes the acceptance of multiplicity.11 Multiplicity is a fact of immediate experience, since being that changes undergoes successive multiplicity. Being that changes and undergoes successive multiplicity has to be made of more than one element or principle. Aristotle reasons from obvious experience, like the change of something from colored to white, which has to have a starting point of change, which is something colored (terminus a quo) and an ending point of change, which is something white (terminus ad quem).12 However, Aristotle also recognized the need for some common ground to supply continuity between one term and to another, from the colored thing to the white thing. Aristotle provided philosopher with a third term in the process of change, a subject. It is the subject that makes change intelligible, since the subject in privation to a form (a non-white thing) acquires that form (becomes a white body). Therefore Aristotle concludes that no more than three principles are necessary to explain every change in the physical world.13 First, there must be a subject that undergoes the change: matter. Second, there must be a determination received by the subject: form. Third, there must be a antecedent absence of this determination: privation.

Aristotle’s adversaries to the Hylemorphism are the Eleatics who denied the very possibility of change, and so did away with the problem of the ultimate principles of natural being. Anaxagoras went to the other extreme, and maintained that the principles were infinite.14

Aristotle confronted and refuted both these views (Aristotle Physics 1. 8). The Eleatics, like Parmenides, asserted that becoming is impossible, because being cannot come from being (this already is), and it cannot come from non-being, which they said was utter nothingness. Aristotle answered that generation or becoming springs from both a kind of being (the subject, matter) and from a kind of non-being (privation).15 Aristotle also proposed another answer to the Eleatic difficulty, that change is possible because between being and nothingness, there is an intermediate state, which is being in potency.16 So, for example in something becoming white, what is white in potency becomes white in act.

Aristotle also was concerned to defend substantial change (Aristotle De Generatione et Corruptione 1. 2. 315 a 26-28). Substantial change was philosophically impugned by two separate schools of thought.17 Thales, Anaximander, and Anaximenes held all things were made of the same ultimate element, so all change came to mere accidental modification of some primordial substance, like air, earth, water, or fire. Another group of philosophers, the Atomists, also Empedocles and Anaxagoras, supposed several specifically distinct elements, but change in those elements was no more than association or dissociation of pre-existent elements, each retaining its separate and distinct nature, so that all change came to a mere accidental modification. In substantial change, such as in evolution, the pre-existent substance ceases to be and a completely new substance comes to be. But if the substratum either had its own determinate nature, or had a plurality of elements already invested with their own specific determination, the new subject would not be one specific nature, but be a composite of two or more natures. Now, some underlying principle is necessary because every generation requires a subject. In substantial change, therefore, the subject cannot be a substance (ens quod), but must be a principle without any positive determination whatever, a principle (ens quo) to which we give the name "prime matter."

The first group of adversaries deny composition from material and form, and also all essential difference between any bodies.18 These are the Mechanicists19 and Mitigated Mechanicists, also called Dynamists.20 The Mechanicists admit extended atoms and motion, and at most some purely motive forces. The Dynamists admit extrinsic and intrinsic forces, like Tongiorgi, who admits material resistence, and Newton, who admits just two forces, attraction and repulsion.21 Hellin replies that this opinion cannot be admitted because of the contradiction between the two seeming similar opinions.22 The Mechanicists deny any powers which cannot be reduced to local motion, and the Dynamists deny the formal extention of bodies.23 Akin to these philosophies are the Empiricists, like John Locke, who only admit sensible impressions and who never concede the existence of substance. For Locke substance is a reality, but an unknown substratum for sensible qualities.24 The Empiricists have no answer to the composition of substance because they do not ask the question; so evolution, which is the process of departing from one substance and acquiring another substantial form, must be philosophically unexplained by the Empiricists.

A second group of adversaries admit substantial forms, but not prime matter.25 They admit substantial forms in order to account for substantial change. They deny prime matter, because they allege that the subjects moving from one state to another are protons and electrons.26 They acquire the form of this or that atom, but do not acquire or lose the state of such protons or electrons.

The third opinion is that commonly held by the Neo-Scholastics. Elementary bodies are composed of prime matter and substantial form, united as from substantial potency and act, which potency and act are really distinct. There is some difference of opinion among Neo-Scholastics about the ulterior determinations of material, form and the composite. Hellin notes that Aristotle founded his Hylemorphism on the view that there cannot be a discontinuity of atoms, while most Neo-Scholastics hold Hylemorphism which admits the theory discontinuity and Scientific Atomism27. This opinion is most common and admitted by Neo-Scholastics such as Fabri (1607-1683), Zanchi (1710-1762), Hauser (1713-1762), and Liberatore (1810-1892). The disputed point is not a major one and Calcagno, who cites other professors at the Gregorian University such as Boyer and Hoenen, does not even bring up any difference of opinion.28 Calcagno views the essentials as enough to verify substantial change, and substantial change is precisely what is involved in evolution of species.

Adversaries who reject the proposal make it clear that the thesis proposed is a serious subject for discussion. The thesis proposed and defended as true presents an objective problem worthy of dialogue.

Adversaries who seriously contradict the proposal in this chapter deserve respect. These adversaries have reasons for their position. In every false position there is some truth. In dialogue, every attempt should be made to clarify that truth. In this case, Renard29 and Calcagno30 both note the need to argue from substantial change. Even some Scholastics, such as William of Occam31 or Duns Scotus,32 had serious, even fatal, problems for their philosophy when they considered the principle of individuation differently that the hylemorphic system. The deeper reason why there is a problem with understanding the hylemorphic theory is that while matter as pure potency is not nothing, and it is a reality, prime matter cannot be conceived by the imagination.33 Accordingly, even if our proposal and its proofs demonstrate the adversaries wrong, their reasoning can be understood and respected.


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