The first argument is from the Principle of Causality. Whatever moves is moved by another. But that other mover creating
a new species is either the first cause alone (Fixism) or includes secondary causes (Evolutionism). But secondary causes are
naturally sufficient to produce the effect of new species. Therefore, included in the origin (causality) of species is secondary
The major premise of the above argument is the principle of causality.53 The minor premise is a compete dichotomy:
either first cause alone, or all causes. The second minor is supported by the principle of sufficient reason, since secondary
causes are naturally sufficient.54 The conclusion follows, joining causality with secondary causes, which are evolutionary.
The second argument is from the Principle of Sufficient Reason. A sufficient reason establishes certainty or possibility.
Evolutionism is a sufficient reason. Therefore, Evolutionism is philosophically possible.
The major premise of the argument from the principle of sufficient reason is the principle of sufficient reason itself.
Noted, however, is that the sufficiency of the reason determines certainty or possibility. The minor premise states that Evolutionism,
which is the origin of species by secondary causes, is a sufficient reason for origin of species. This minor premise, secondary
causes are sufficient reason, must be proved.55 Then, Evolutionism (philosophical origin of species by secondary
causes) is at least philosophically possible.
The proof of the minor premise, of the argument from the principle of sufficient reason, comes from a number of Neo-Scholastic
philosophers. Arguments here are given in summary form. Klubertanz argues that substantial changes are caused by created secondary
agents and always take place through accidental change, which accidents are agents of substance, through material dispositition.56
Renard argues that secondary causality occurs by accidental becoming which prepares and disposes the substance, at least a
longe, for such a change (generatio substatialis).57 Hoenen argues that secondary causality is the intrinsic
mutability of accident and substance educed from the potency of the material by the form.58 Dougherty argues that
secondary causality comes into operation when God suspends the properties of nature directing them to other than their connatural
effects.59 Dezza argues that secondary causality is the immanent virtuality placed by the creator in the very nature
of species, so that if circumstances are appropriate, the substantial change takes place.60 O’Flynn Brennan
argues that secondary causality is the passive inclination of matter always desiring the more perfect to fulfill its potency.61
Accordingly, the minor premise of the argument from sufficient reason is proved, at least in part. A number of Neo-Scholastic
philosophers have successfully argued that secondary causality is a sufficient reason for natural origin of species. Therefore,
Evolutionism is philosophically possible.
Space does not permit the examination of every theory of secondary causes of evolution, but a speculative question arises
as to how many theories of secondary causes can exist without repeating the same area of argumentation. Such a difficult question
has never been considered. Further, it is not in the purview of this dissertation to explore metaphysics, but rather the philosophy
of nature. Nevertheless, it appears that only six theories are possible. Form is either substantial or accidental. Prime matter
is either substantial or accidental. Aristotle adds privation as the third element of change, and something can have substantial
privation or accidental privation. This yields six alternatives. When the six theories just given are reconsidered, the following
results appear. The suspension theory of Dougherty relates to substantial form. The accumulation theory of Klubertanz relates
to accidental form. The passive inclination theory of O’Flynn Brennan relates to substantial privation. The eduction
theory of Hoenen relates to both substantial and accidental privation. The immanent virtuality theory of Dezza relates to
substantial matter. The dispositive theory of Renard relates to accidental matter. Prima facie it appears that any
other philosophical theory affirming and explaining the natural secondary causes of evolution would be a repetition of the
general theories already given.
At least one philosophical theory of how evolution is possible in operation should be examined in depth. Klubertanz appears
to give the most extensive presentation, and does explain in considerable philosophical depth. When Klubertanz is examined
here, reference will be made to the parallel presentation in St. Thomas. Klubertanz does not cite St. Thomas often. It is
not the intention here to show that Klubertanz is a Thomist, but to show the continued influence of the philosophy of St.
Thomas. There is a strict correlation between the presentation of the philosophy of St. Thomas in the above section "Thomistic
Roots" and the major parts of the presentation of Klubertanz.
The essential argument of Klubertanz is that accidents of the agent (form) and patient (matter) are instruments of substance,
so a new substance can be made by them.62 This is the philosophical explanation of what the scientific theory of
evolution, by which a very large number of kinds of living things has been derived by means of a tremendously long series
of usually very small (perhaps occasionally large) accumulation of changes, from a very few (perhaps only one) living ancestors.63
Further, this is very close to St. Thomas saying, "The emanation of proper accidents from the subject is not by way of transmutation,
but by a certain natural result" (Aquinas Summa Theologiae 1. 77. 6 ad 3).
Klubertanz inquires, "Does substantial change exist, and how does it take place?"64 Substantial change caused
by created agents always takes place through accidental change, through material dispositions. Proof of this is that creation
is power over being itself, which indicates a sufficient reason for the own being of the creator (confer: Aquinas Summa
Contra Gentiles 2. 16). But power over being itself is not found in creatures, so creatures need pre-existing matter to
act. God acts through secondary causes (Aquinas Summa Theologiae 1. 105. 5).65 St. Thomas also holds secondary
agents of substantial change (Aquinas De Principiis Naturae, 6) and a certain unity of substance and accident (Aquinas
Summa Theologiae 1. 11. 1 corpus). Examples of this substantial change are assimilation of food, production
of synthetic rubber, heat making molecules move faster (physics), or instability of living molecules under high heat (chemistry).
Klubertanz adds that the accidental change involve material dispositions. Squeezing a metal ring turns a circle into an ellipse,
and the cause is the person (efficient cause) and the matter. Water temperature rising from 30E
to 80E in the test tube is caused by the scientist (efficient cause) and the proximate dispositions
of the matter.66 The material plays a part in the change by placing limits on the efficient cause, because you
cannot get a hammer out of beeswax, nor water from chlorine and oxygen. These views are similar to St. Thomas (Aquinas Summa
Theologiae 3. 76. 6 ad 1). Klubertanz notes that the synthesis of compounds takes place in successive stages, not leaps,
in the laboratory. Scientists have found by experience that synthesis and destruction of very complex compounds does not take
place in a single leap, but in successive stages. This is noted by St. Thomas that God in the beginning creates all species
together not in actual from but "in power and almost as in a seed" ("in virtute et quasi in semine," Aquinas Summa
Theologiae 1. 66. 4).
Klubertanz continues to elaborate his theory of evolution not just with regard to tranformation, but with regard to progress
of species from lower species to higher species.67 This is an affirmation of finality, which is the next chapter.
Due to finality in creation, Klubertanz holds essential evolution of living things up to and including the human body (the
whole man with his spiritual soul excluded). His treatment of finality involves the added concepts of equivocal causality,
chance, and God’s Providence as the possible explanation of living things. Klubertanz endorses essential Evolutionism
as a possible explanation of living things.
Does Klubertanz affirm monophylactic evolution (one stem of all life) or polyphylactic evolution (many stems of life)?
Klubertanz does not use this terminology. However, it appears that he would endorse monophylactic evolution. His definition
of scientific evolution has life evolve "from a very few (perhaps only one) living ancestors."68 Further, Klubertanz
states, "We would suppose the development process would begin with a rather simple relatively undifferentiated form of life,
and proceed by way of extremely small but sudden changes."69