Make your own free website on

Philosophy of Evolution: Reasoning Problem

The Scholastic "Probable Argument"



The Neo-Scholastic Argumentatio Probabilis

The Neo-Scholastic Raymond Nogar claims that the fact of evolution can be proved from concordant evidence with the help of the expert testimony of scientists. Nogar notes that "the fundamental fact of evolution seems to be settled once and for all" among scientists, and "this may be true within that small group of professional workers in scientific fields, but it is not the case with the intelligent non-scientist who has little opportunity to follow the course of evolutionary development."33 In reply, other Neo-Scholastics note, "For many scientists, a theory is considered proved when it affords valuable understanding, and leads to further hypotheses, understandings and information."34 However, even this acceptance as a proved hypothesis is not admitted by scientists in the same way or within the same limits.35 Even when evolution is admitted by scientists, the Neo-Scholastics note that the scientists do not know how to offer valid arguments for evolution36, and the arguments that are offered "do not even prove that it (evolution) is possible."37 Against this Nogar proposes an argument based on two factors: authority of experts and the convergence of scientific evidence.38 Nogar states, "The authority of the specialists’ judgement in a matter of evolution, like every other area of high specialization, is great."39 Further, Nogar argues that there is a consensus among experts.40 In addition to expert opinion, Nogar argues convergence of evidence.41 Although Nogar does not explicitly use the argument from the lack of an alternative, it is notable that Nogar considers a possible alternative, Creationism, with the comment that it "has little support in the evidence brought forward by science."42 Actually, it is Fixism that is the real opponent to Evolutionism, but Nogar does not use the argument against alternatives, except for a few pages on sequential Creationism.43 At the end of the factual evidence, Nogar concludes, "The fact of evolution is more probable."44 Other Neo-Scholastics give rules for the legitimacy of arguments from a hypothesis: the hypothesis must be possible; the hypothesis must not be contrary to scientific observation; and the conclusion must not be proposed as a certain or unique truth.45 There is a Neo-Scholastic probable argumentation (agumentatio probabilis), which is defined as argumentation in which from probable premises is drawn a probable conclusion.46 As far as form, the probable argument does not differ from the apodictic syllogism which yields certitude and necessity, but in its probable premises the probable argument yields only a probable opinion. The opinioniative conclusion of this probable argument can arise from intrinsic reasons, such as hypothesis, analogy, or statistics; or the opinioniative conclusion can arise from extrinsic reasons, such as had in testimony, which is based on the statements of others in which one places faith. These are two of the elements in the argument of Nogar, namely the hypothesis supported by convergent evidence and testimony of experts. When there is convergence of probability there are judgments, which are independent among themselves and which have only probability. The convergence, however, offers a new motive or reason which surpasses those probabilities, and then such a probable argumentation can cause true certitude.47 Nogar eventually claims "Finally, he (the unbiased reader) has practical certitude that the evolutionary hypothesis is for the present the most fruitful one available for biological research."48 Other Neo-Scholastics agree that by the convergence of probable things there can often be reductive certitude in areas such as legal court cases and history.49 Therefore, one can answer with Norgar that the fact of evolution can be proved by testimony of experts and the convergence of evidence from many fields. Nevertheless, that proof is only within the realm of probability for several reasons. First, any certitude is diminished by the arguments that would undermine the syllogism, as argued in the whole chapter above. Second, the Neo-Scholastics note that probable argumentation (argumentatio probabilis) is formally no different from apodictic argumentation, but differs because the conclusion is only probable. Thirdly, Nogar himself admits that assent to the evolutionary hypothesis is not theoretical, that is, a judgment that a certain proposition is objectively true concerning the facts of the case, but rather assent to the evolutionary hypothesis is only practical, which indicates a judgment that a certain course of action is the best one to take under the circumstances and in view of the available information.50

Author: John Edward Mulvihill, S.T.D., D.Min., Ph.D.
Copyright 2009 by the Genealogist, 3236 Lincoln, Franklin Park, IL 60131 U.S.A.