Aristotle's On Interpretation Ch. 8. 18a13-18a27: An assertion ought not to merely appear simple, it ought to truly be simple. A recapitulation and a conclusion to this chapter
(18a13-18a27) of Ch. 8: An assertion ought not to merely appear simple, it ought to truly be simple. A recapitulation of what we have so far learned and a conclusion to the present chapter
In the first four chapters of On Interpretation, Aristotle introduces concepts that form the building blocks of assertions. He names them and discusses what they are (e.g. nouns and verbs) as well as how they come together to form assertions.
From Ch. 5 onwards, the philosopher centers his attention on the assertion as such. Through his instruction, he moves us from a very rough understanding of what constitutes an assertion to a fairly sophisticated one. He first draws distinctions (i) between simple and compound assertions, (ii) assertions formulated about a particular as opposed to a universal as subject, (iii) assertions applied universally as opposed to non-universally. At the same time, Aristotle discusses the way in which assertions which signify the same thing of the same thing may oppose each other. He lays out the differences between assertions which oppose each other as (i) contradictories, (ii) contraries and (iii) the opposites of contraries.
Throughout his demonstration, Aristotle sets contradiction apart from all the other relations of opposition. He remarks that in pairs of contradictories one assertion is always true and the other false no matter the underlying circumstances. For this reason, he centers our focus on contradictory assertions because of their utility and straightforwardness in determining what is true and what false. Not every pair of contradictory assertions is straightforward in this way, however. Only in some contradictory pairs do we find one assertion to be necessarily true when the other is false, or necessarily false when the other is true.
As such, starting with Ch. 7, the philosopher pursues to investigate and identify in which pairs of contradictories it is the case that we will always find one assertion to be true and the other false, and in which ones this is not the case.
In Ch. 8 18a27 Aristotle acknowledges that it is not necessary for a compound assertion to be true when we prove its contradictory to be false. This happens to be the case regardless of how we formulate our compound assertion.
To demonstrate this, in Ch. 8 18a18-18a26 the philosopher takes up the curious case of compound assertions which are formulated as simple assertions. He instructs us that when we conflate two concepts and express them in an assertion as e.g. one noun or verb, that we are in fact making a compound assertion and not a simple one. For example, if in the assertion “Socrates is wise” we refer to both the historical Socrates and Plato’s Socrates, we are in fact asserting wise of two subjects and not just one. We may thereby also express the assertion as “the historical Socrates and Plato’s Socrates are wise” or “the historical Socrates is wise and Plato’s Socrates is wise”.
The key to understanding this subtlety lies on what Aristotle means in Ch. 8 18a13-18a17 when he defines a simple assertion as signifying one thing of one thing. Here, an inquiry into what the philosopher means with “one thing” presents itself as a crucial step to interpreting this chapter.
We have thus arrived at the end of Ch. 8. Next week we will take up Ch. 9.
Key points: (i) The current focus of our investigation is to identify all those pairs of contradictory assertions in which one assertion is necessarily true and the other necessarily false regardless of the set of circumstances underlying them. (ii) It is not required for a compound assertion to be true when we prove its contradictory to be false. Thus, we will no longer consider compound assertions in our present investigation.
