Analysis of a Proposition. Every Proposition must have a noun and a verb — it must be proposition of Something. False propositions, involve the Form of Non-Ens, in relation to the particular subject.
Let us look attentively what Proposition, Judgment, Opinion, are. As we said about Forms and letters, so about words: it is not every combination of words which is possible, so as to make up a significant proposition. A string of nouns alone will not make one, nor a string of verbs alone. To compose the simplest proposition, you must put together at least one noun and one verb, in order to signify something respecting things existing, or events past, present, and future.[80] Now every proposition must be a proposition about something, or belonging to a certain subject: every proposition must also be of a certain quality.[81] Theætêtus is sitting down — Theætêtus is flying. Here are two propositions, both belonging to the same subject, but with opposite qualities: the former true, the latter false. The true proposition affirms respecting Theætêtus real things as they are; the false proposition affirms respecting him things different from real, or non-real, as being real. The attribute of flying is just as real in itself as the attribute of sitting: but as respects Theætêtus, or as predicated concerning him, it is different from the reality, or non-real.[82] But still Theætêtus is the subject of the proposition, though the predicate flying does not really belong to him: for there is no other subject than he, and without a subject the proposition would be no proposition at all. When therefore different things are affirmed as the same, or non-realities as realities, respecting you or any given subject, the proposition so affirming is false.[83]
[80] Plato, Sophist. pp. 261-262.
[81] Plato, Sophist. p. 262 E. λόγον ἀναγκαῖον, ὅταν περ ᾖ, τινὸς εἶναι λόγον· μὴ δέ τινος ἀδύνατον … Οὐκοῦν καὶ ποῖόν τινα αὐτὸν εἶναι δεῖ;
[82] Plato, Sophist. p. 263 B Ὄντων δέ γε ὄντα ἕτερα περὶ σοῦ.
That is, ἕτερα τῶν ὄντων, — being the explanation given by Plato of τὰ μὴ ὄντα.
[83] Plato, Sophist. p. 263 D.
Opinion, Judgment, Fancy, &c., are akin to Proposition, and may be also false, by coming into partnership with the Form Non-Ens.
As propositions may be true or false, so also opinion or judgment or conception, may be true or false: for opinion or judgment is only the concluding result of deliberation or reflection — and reflection is the silent dialogue of the mind with itself: while conception or phantasy is the coalescence or conjunction of opinion with present perception.[84] Both opinion and conception are akin to proposition. It has thus been shown that false propositions, and false opinions or judgments, are perfectly real, and involve no contradiction: and that the Form or Genus — Proposition, Judgment, Opinion — comes properly and naturally into partnership with the Form Non-Ens.
[84] Plato, Sophist. pp. 263-264. 264 A-B: Οὐκοῦν ἔπειπερ λόγος ἀληθὴς ἦν καὶ ψευδής, τούτων δ’ ἐφάνη διάνοια μὲν αὐτῆς πρὸς ἑαυτὴν ψυχῆς διάλογος, δόξα δὲ διανοίας ἀποτελεύτησις, φαίνεται δὲ ὃ λέγομεν (φαντασία) σύμμιξις αἰσθήσεως καὶ δόξης, ἀνάγκη δὴ καὶ τούτων τῷ λόγῳ ξυγγενῶν ὄντων ψευδῆ τε αὐτῶν ἔνια καὶ ἐνίοτε εἶναι;