In these propositions, as in the others before noticed, the same relation prevails between C and B, and between A and D; if C be true, B also is true, but not _vice versâ_; if A be true, D also will be true, but not _vice versâ_. But the propositions diagonally opposed will not be so often alike true:[26] thus, if A be true (_Omnis est homo justus_), C cannot be true (_Omnis est homo non justus_); whereas in the former quaternion of propositions (indefinite, and therefore capable of being construed as not universal) A and C might both be alike true.[27] [Footnote 26: Aristot. De Interpret. p. 19, b. 35. [Greek: plê\n ou)ch o(moi/ôs ta\s kata\ dia/metron e)nde/chetai sunalêtheu/ein; e)nde/chetai de\ pote/.] The "diameter" or "diagonal" is to be understood with reference to the scheme or square mentioned p. 119, note, the related propositions standing at the angles, as above.] [Footnote 27: The Scholion of Ammonius, p. 123, a. 17, Br., explains this very obscure passage: [Greek: a)ll' e)pi\ me\n tô=n a)prosdiori/stôn] (indefinite propositions, such as may be construed either as universal or as particular), [Greek: kata\ tê\n e)ndechome/nên u(/lên ta/s te katapha/seis] (of the propositions diagonally opposite), [Greek: sunalêtheu/ein a)llê/lais sumbai/nei kai\ ta\s a)popha/seis, _a(/te tai=s merikai=s i)sodunamou/sas_. e)pi\ de\ tô=n prosdiôrisme/nôn] (those propositions where the mark of universality is tacked to the Subject), [Greek: peri\ ô(=n nuni\ au)tô=| o( lo/gos, tê=s katho/lou katapha/seôs kai\ tê=s e)pi\ me/rous a)popha/seôs, ta\s me\n katapha/seis a)du/naton sunalêtheu=sai kath' oi(andê/pote u(/lên, ta\s me/ntoi a)popha/seis sumbai/nei sunalêtheu/ein kata\ mo/nên tê\n e)ndechome/nên;] &c.] It is thus that Aristotle explains the distinctions of meaning in propositions, arising out of the altered collocation of the negative particle; the distinction between (1) _Non est justus_, (2) _Est non justus_, (3) _Est injustus_. The first of the three is the only true negative, corresponding to the affirmative _Est Justus_. The second is not a negative at all, but an affirmative ([Greek: e)k metathe/seôs], or by transposition, as Theophrastus afterwards called it). The third is an affirmative, but privative. Both the second and the third stand related in the same manner to the first; that is, the truth of the first is a necessary consequence either of the second or of the third, but neither of these can be certainly inferred from the first. This is explained still more clearly in the Prior Analytics; to which Aristotle here makes express reference.[28] [Footnote 28: Aristot. De Interpr. p. 19, b. 31. [Greek: tau=ta me\n ou)=n, ô(/sper e)n toi=s A)nalutikoi=s le/getai, ou(/tô te/taktai.]