This is part 2 of "The Intellligibility of Singulars"

The author extends his warm thanks for your comments on the previous posting and invites any further comments you might have.

Moreover, I intend this discussion to be a contribution to the overall knowledge base of the site, as I could not find any other contributions on the subject.

Now, it should be seen that though this difficulty is one which Aristotle himself does not explicitly recoginze and attempt to explain, Aquinas recognizes the problem quite clearly and tries to resolve the questions which pertain to it. This may be seen beginning at I-I, 84,1, where, in arguing against Plato’s position that sensible things are unknowable, Aquinas notes that if Plato is right about the nature of the Forms, and they are self-subsistent and separate from material things, then there is no chance that material things may be known: for the object of knowledge will then not be material things but immaterial Ideas. Moreover, this would make demonstration in terms of efficient and material causes impossible (since the Forms do not admit of such types of explanation), which would in turn rule out demonstration in natural science. As will be seen, Aquinas counters the concerns put forward above by presenting knowledge as founded upon experience and as being complete precisely when it explains our experience. This will be the foundation for his position which he holds in common with Aristotle; nevertheless, it is clear that more will have to be said to see exactly how the contingencies of the natural world may be made demonstrable.

Lastly, Aquinas suggests that Plato’s motivation for positing a world of subsistent Forms was his understanding that the intellect required universality and necessity as conditions for knowledge-a position which answers to supposed Heraclitean doubts about the intelligibilty of things in the world. Aristotle and Aquinas both agree with these conditions for knowledge, though again, they see no necessity thereby for positing forms as ontologically separate from matter; rather, natural science will become possible precisely because there is universality and necessity to be found in things, which, in terms of singulars, may be seen in their essences and definitions. Nevertheless, again, it remains to be seen how such necessity applies to singulars themselves, such that one might demonstrate something to be true in every case of a particular. Aquinas senses this problem in 84,1 ad. 3, where he writes that even in changing things there are “unchanging relations”, and gives as an example the proposition that Socrates is sitting, and comments that although it is not always true that Socrates is sitting, it is always true that he is sitting when he is sitting. This explanation echoes Aristotle’s Metaphysics Γ, as does much of 84,1. Obviously, more will have to be said to see how Aquinas resolves such questions.

The following five questions will be answered in pursuing the investigation of this difficulty: (I.) What is Aquinas' position regarding the intelligibility of particulars? (II.) If particulars are intelligible through universals, does the recognition of their universal aspects add any necessity to them as particulars? (III.) Is it necessary to posit an existential quantifier in order to make statements about the natural world intelligible? (IV.) Is demonstration possible in natural science? Is it possible to demonstrate something to be necessarily true of a particular? Having answered these questions it will become more clear what the relationship is between demonstration and natural science with respect to Aristotle’s requirements for knowledge.

I. What is Aquinas’ position regarding the intelligibility of particulars?

The primary text which responds to this question is to be found in Summa Theologiae I-I, 86,1, which asks whether our intellect knows singulars. It may readily be seen that Aquinas’ text here amounts to summative interpretation of various texts in Aristotle, including the Physics and De Anima. Aquinas has just finished discussing the way in which the soul knows material things by means of universals in Q. 84, and in Q. 85 he turns toward the psychology of the intellect’s abstraction of universals from singulars and its reflection upon them. The two questions together, in brief, give us Aquinas’ position that the senses apprehend particulars while the intellect apprehends universals relationally, by means of particulars. The intellect is able to know singulars in the light of its understanding of universals: for the intellect knows the universals which are present in singulars, and is able understand the universal aspects of material things as they are present to the mind as intelligible species.

Thus, both a sensory acquaintance with things as singulars as well as an intuition of their universal characteristics is required for a complete knowledge of a material thing. One may see here a reflection of the learning process which was described in the opening section: the necessary condition for knowledge is our coming to know the universal, but this is not, by itself, sufficient for complete scientific knowledge; rather knowledge of material things must be knowledge of or about something outside the soul in the material world of things. Again, if knowledge of the material world is strictly relational (necessarily including the universal and particular or the thought and what it is about), it follows that, in order to be fully intelligible or complete, both terms of the relation must be present, and it is evident that one term, the material thing, is known iff it is completed by the universal immaterial term which must accompany it. Likewise, the universal term is only intelligible within the structure of the relation if it is completed by the singular. Thus far, an epistemological question is largely answered, in a preliminary way, in terms of pyschology and logic; but one may see the necessity of such an exposition: for it describes the conditions for knowledge which frame Aquinas’ discussion, and it is this framework which will allow for an empirical approach to the knowldege of things in the world informed by concepts, without which episteme and scientia would not be possible.

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We come now to a question which was posed earlier: how might we understand Aquinas in 84,1 ad. 3 when he gives “Socrates is sitting” as an example of a proposition which is susceptible of being known in a scientific way? This question is both difficult and quite important, for here Aquinas appears to be asserting that there is universality and necessity even in things which are purely accidental. It is difficult because it is not clear that even Aristotle could possibly hold such a position, and here it seems that Aquinas is driven to say such odd things because he sees the need for positing necessity in the case of the particular in order to make empirical science demonstrable. This difficulty emerges clearly before us if we consider that Aquinas has argued that the proposition “Socrates is sitting” is true precisely when Socrates is in fact sitting: thus it cannot be true that this proposition is susceptible of being true always, for it is possible that Socrates may not now be sitting; rather, (1.) it appears that the statement is only contingently true, so that it may be true provided certain material conditions hold. But (2.) Aquinas claims that there is nothing to hinder there being scientia of such things. Now, (3.) since scientia is of the necessary, it appears that this is impossible.

Two possible routes of explanation appear before us: (a.) Q. 86,3 where Aquinas discusses whether contingent things are intelligible, and (b.) as noted above, Metaphysics Γ, and especially chapter 5, where Aristotle discusses the possibility of truth in changeable things.

Turning first then to 86,3, we notice that Aquinas’ original argument in 84,1 ad.3 was not a mere oversight or just something he might have tossed out for example’s sake during dictation, but is in fact his considered opinion: for he repeats the argument here in 86,3 again only with a variation in the terms. This time he proposes to show that even a statement such as “Socrates is running” is an example of a statement which is indeed contingent in one way, but necessary in another.

What might be taken as the major premise of his argument appears where he writes that there is nothing contingent which does not have in it something which is necessary. This statement is justified partly on metaphysical grounds, and partly on the basis of the way in which Aristotle discusses the relationship between contingency and necessity in terms of his modal logic. Metaphysically then, Aristotle and Aquinas both argue that the necessary must always precede the contingent.