If we compare the two foregoing counter-demonstrations (7 and 6), we shall see that the negative results of the seventh follow properly enough from the assumed premisses: but that the affirmative results of the sixth are not obtained without very unwarrantable jumps in the reasoning, besides its extreme subtlety. But apart from this defect, we farther remark that here also (as in Numbers 1 and 2) the fundamental principle assumed is in terms the same, in signification materially different. The signification of _Unum non est_, as it is construed in Number 7, is the natural one, belonging to the words: but as construed in Number 6, the meaning of the predicate is altogether effaced (as it had been before in Number 1): we cannot tell what it is which is really denied about Unum. As, in Number 1, the proposition _Unum est_ is so construed as to affirm nothing except _Unum est Unum_--so in Number 7, the proposition _Unum non est_ is so construed as to deny nothing except _Unum non est Unum_, yet conveying along with such denial a farther affirmation--_Unum non est Unum, sed tamen est aliquid scibile, differens ab aliis_.[101] Here this _aliquid scibile_ is assumed as a substratum underlying _Unum_, and remaining even when Unum is taken away: contrary to the opinion--that Unum was a separate nature and the fundamental Subject of all--which Aristotle announces as having been held by Plato.[102] There must be always some meaning (the Platonic Parmenides argues) attached to the word Unum, even when you talk of _Unum non Ens_: and that meaning is equivalent to _Aliquid scibile, differens ab aliis_. From this he proceeds to evolve, step by step, though often in a manner obscure and inconclusive, his series of contradictory affirmations respecting Unum. [Footnote 101: Plato, Parmenid. p. 160 C.] [Footnote 102: Aristot. Metaph. B. 1001, a. 6-20.] The last couple of Demonstrations--8 and 9--composing the fourth Antinomy, are in some respects the most ingenious and singular of all the nine. Si _Unum non est_, what is true about Cætera? The eighth demonstrates the _Both_ of the affirmative predicates, the ninth proves the _Neither_. [Side-note: Demonstrations VIII. and IX.--Analysis of Demonstration VIII.]