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.65
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.66 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.67 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.68
Certitude could arise from some observable fact or experiment. However, there is no experiment to prove evolution or abiogenesis.69
However, some restricted observation of evolution is possible within species.70 Klubertanz uses the concepts of
equivocal causality, chance, and Providence, to explain the possible origin of living things.71 The effects of
equivocal causality and chance can be seen in human efforts to improve breeds of plans and animals. Providence, or the effects
of final causality in the universe, can be viewed as bringing order into the cosmos, rather than undirected chaos.72
Certitude could arise from some philosophical explanation that exists. Explanations were given by several Neo-Scholastics,
especially Klubertanz in equivocal generation, Dezza in immanent virtuality, Palmes in divine intervention, and Modin in programmed
evolution.
Certitude could arise if the argumentation was based on some philosophical principles. The origin of life by abiogenesis
is philosophically based on the principle of finality.73
Certitude could arise if the explanation is sufficient, due to the principle of sufficient reason. Klubertanz gives a sufficient
reason for abiogenesis when he explains, "The same explanation can perhaps be used for the origin of life itself. It is again
possible that the right chance occurrence of a whole group of particular lines of causality, unified in the divine plan, should
result in the formation of a single living cell." 74
Certitude could arise if the explanation of abiogenesis was rooted in St. Thomas Aquinas, thereby being faithful to tradition.
St. Thomas reprises Aristotle who taught that "nature proceeds little by little from things lifeless to animal life" and "there
is observed in plants a continuous scale of ascent toward the animal."75 This observation of natural ascent is
helpful to understand the evolutionary progress from lifeless to life.76
Certitude could arise if Neo-Scholastics agree on the possibility of abiogenesis. In 1909, Joseph Gredt argued against
abiogenesis, but only if it excluded the prime cause of nature.77 Modern Neo-Scholastics do not exclude God, but
are much more open, not only due to the advances in science, but also due to more mature reflection in the philosophy of nature,
as exemplified by Klubertanz, 78 Dezza,79 Adler,80 and Mondin.81
Certitude could arise due to recent scientific confirmation by convergent scientific arguments. A scientific problem exists
because no one was present at the origin of life in the past, and life has not yet been produced in the modern laboratory.82
In 1953 and 1954, the chemists Stanley Miller and Harold Urey exposed a mixture of hydrogen, methane, ammonia and water to
the continuing action of an electrical discharge in a sealed vessel, duplicating in the laboratory what is thought to be the
conditions of the primitive earth. The significant thing about the Miller-Urey experiment is that it resulted in the presence
of some organic compounds, including amino acids, the building blocks of proteins. Nevertheless, life was not produced in
the laboratory yet.83 Klubertanz notes that these scientists use the natural, necessary, predetermined activities
of various natural compounds, and acting intelligently as unifying causes try to find the right combination of interfering
causalities which would produce the material dispositions requisite for the production of life. If they succeed, the living
result of their efforts will be produced by equivocal causality under the formal unification of the secondary, dependent providence
of the mind of the scientist, so that the material elements and compounds would be the instruments of the human cause, which
will be relative to the material the principal cause.84 Other replies to the current lack of success in the production
of life are three. First, life needs a sufficient reason for its existence, and the simple and natural explanation for life
would be through secondary causality. Secondly, science looks for order in the universe.85 Abiogenesis planned
by the creator would be closer to a slowly developing pattern of order, rather than some explanation of the origin of life
by alternative intervention. Finally, Klubertanz notes that 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.86 By analogy, these same natural processes would slowly move
from the inanimate to the animate.
Certitude could arise if the opposite opinion is not tenable. While it is possible that the origin of life is by immediate
creation, this does not seem to be necessary, since there is a material soul of plants87 and animals.88
God usually works, in the natural order, through secondary causes He has made.89
Certitude could arise if the objections of adversaries are able to be answered. The two philosophical objections to abiogenesis
are, first, there is nothing in an effect which was not in some way in the cause, and second, that every agent acts according
to its nature (omne agens agit sibi simile).90 The reply to both is substantially the same: while the objection
assumes one line of causality, the real world often brings multiple lines of causality to bear on one effect. Therefore, in
the first case, while a single effect may have something that a single cause may lack, many causes can bring about an aggregate
greater effect. In the second case, every agent (material) acts according to its nature (inorganic), but should multiple lines
of causality intersect, an non-similar and different (organic) effect could arise.
Certitude can be had from the possibility of philosophers and theologians admitting this mode of origin without damage
to their other beliefs. Dezza, the philosopher at the Gregorian University, notes, "There is no prohibition on continued research
or multiplying experiments in the laboratory."91 Although cautious, in fact, Pope John Paul II does not exclude
abiogenesis.92 Further, Mondin notes that God is the proportionate cause of life whether the origin of life is
immediate or mediate.93 Mondin states that this should satisfy philosophy, since "proportionate cause" is both
an application of the principle of causality and if "proportionate"even in the case of abiogenesis, this would satisfy the
principle of sufficient reason.
Certitude can be had from the fact that evolutionary abiogenesis is the best answer now for the origin of life.94
St. Thomas makes a distinction between a "verified" universal (dici de omni) and a "provisional" universal (ut nunc).95
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. Thus, evolutionary abiogenesis based on secondary causality96 is the best answer to the origin of life, and
is the best answer we have now.97
The level of certitude for "evolutionary abiogenesis is probable, but equivocal" is at minimum at the level of the metaphysically
possible and even probable. The proof is the principle of finality, from lower elements to be in service of higher, and also
from the principle of sufficient reason, by which the creator uses secondary causes when available. Further, the convergence
of all of the above arguments are proof, especially the fulfillment of the principle of sufficient reason together with God’s
use of secondary causality. This agrees with the opinion of Klubertanz about the possibility of abiogenesis.98
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.99 This
is the method of Aristotle and St. Thomas.100 Klubertanz notes that the factual (not philosophical) occurrence
of such evolution as the origin of life "is a question of fact whose establishment by any direct means is extremely
difficult if not impossible."101
