Eukleides was a Parmenidean, who blended the ethical point of view of Sokrates with the ontology of Parmenides, and followed out that negative Dialectic which was common to Sokrates with Zeno. Parmenides (I have with already said)[19] and Zeno after him, recognised no absolute reality except Ens Unum, continuous, indivisible: they denied all real plurality: they said that the plural was Non-Ens or Nothing, _i.e._ nothing real or absolute, but only apparent, perpetually transient and changing, relative, different as appreciated by one man and by another. Now Sokrates laid it down that wisdom or knowledge of Good, was the sum total of ethical perfection, including within it all the different virtues: he spoke also about the divine wisdom inherent in, or pervading the entire Kosmos or universe.[20] Eukleides blended together the Ens of Parmenides with the Good of Sokrates, saying that the two names designated one and the same thing: sometimes called Good, Wisdom, Intelligence, God, &c., and by other names also, but always one and the same object named and meant. He farther maintained that the opposite of Ens, and the opposite of Bonum (Non-Ens, Non-Bonum, or Malum) were things non-existent, unmeaning names, Nothing,[21] &c.: _i.e._ that they were nothing really, absolutely, permanently, but ever varying and dependent upon our ever varying conceptions. The One--the All--the Good--was absolute, immoveable, invariable, indivisible. But the opposite thereof was a non-entity or nothing: there was no one constant meaning corresponding to Non-Ens--but a variable meaning, different with every man who used it. [Footnote 19: See ch. i. pp. 19-22.] [Footnote 20: Xenophon. Memor. i. 4, 17. [Greek: tê\n e)n tô=| panti\ phro/nêsin]. Compare Plato, Philêbus, pp. 29-30; Cicero, Nat. Deor. ii. 6, 6, iii. 11.] [Footnote 21: Diog. L. ii. 106. [Greek: Ou)=tos e)\n to\ a)gatho\n a)pephê/|nato polloi=s o)no/masi kalou/menon; o(/te me\n ga\r phro/nêsin, o(/te de\ theo/n, kai\ a)/llote nou=n kai\ ta\ loipa/. Ta\ de\ a)ntikei/mena tô=| a)gathô=| a)nê/|rei, mê\ ei)=nai pha/skôn]. Compare also vii. 2, 161, where the Megarici are represented as recognising only [Greek: mi/an a)retê\n polloi=s o)no/masi kaloume/nên]. Cicero, Academ. ii. 42.] [Side-note: Doctrine of Eukleides about _Bonum_.] It was in this manner that Eukleides solved the problem which Sokrates had brought into vogue--What is the Bonum--or (as afterwards phrased) the Summum Bonum? Eukleides pronounced the Bonum to be coincident with the Ens Unum of Parmenides. The Parmenidean thesis, originally belonging to Transcendental Physics or Ontology, became thus implicated with Transcendental Ethics.[22]