[Footnote 56: Plato, Theætêt. p. 179. [Greek: ei)/ pê| tou\s suno/ntas e)/peithen, o(/ti kai\ to\ me/llon e)/sesthai/ te kai\ do/xein ou)/te ma/ntis ou)/te tis a)/llos a)/meinon kri/neien a)\n ê)\ au)to\s au(tô=|.]] [Footnote 57: Plato, Theætêt. p. 178.] [Footnote 58: Plato, Theætêt. p. 179 B. _Theodor._ [Greek: E)kei/nê| moi dokei= ma/lista a(li/skesthai o( lo/gos, a(lisko/menos kai\ tau/tê|, ê)=| ta\s tô=n a)/llôn do/xas kuri/as poiei=, au(=tai de\ e)pha/nêsan tou\s e)kei/nou lo/gous ou)damê=| a)lêthei=s ê(gou/menai.] _Sokrat._ [Greek: Pollachê=| kai\ a)/llê| a)\n to/ ge toiou=ton a(loi/ê, mê\ pa=san panto\s a)lêthê= do/xan ei)=nai; peri\ de\ to\ paro\n e(ka/stô| pa/thos, e)x ô(=n ai( ai)sthê/seis kai\ ai( kata\ tau/tas do/xai gi/gnontai . . . I)/sôs de\ ou)de\n le/gô, a)na/lôtoi ga/r, ei) e)/tuchon, ei)si/n.]] [Side-note: Plato, when he impugns the doctrine of Protagoras, states that doctrine without the qualification properly belonging to it. All belief relative to the condition of the believing mind.] Such are the objections urged by Sokrates against the Protagorean doctrine--_Homo Mensura_. There may have been perhaps in the treatise of Protagoras, which unfortunately we do not possess, some reasonings or phrases countenancing the opinions against which Plato here directs his objections. But so far as I can collect, even from the words of Plato himself when he professes to borrow the phraseology of his opponent, I cannot think that Protagoras ever delivered the opinion which Plato here refutes--_That every opinion of every man is true_. The opinion really delivered by Protagoras appears to have been[59]--_That every opinion delivered by every man is true, to that man himself_. But Plato, when he impugns it, leaves out the final qualification; falling unconsciously into the fallacy of passing (as logicians say) _a dicto secundum quid ad dictum simpliciter_.[60] The qualification thus omitted by Plato forms the characteristic feature of the Protagorean doctrine, and is essential to the phraseology founded upon it. Protagoras would not declare any proposition to be true absolutely, or false absolutely. The phraseology belonging to that doctrine is forced upon him by Plato. Truth Absolute there is none, according to Protagoras. All truth is and must be truth relative to some one or more persons, either actually accepting and believing in it, or conceived as potential believers under certain circumstances. Moreover since these believers are a multitude of individuals, each with his own peculiarities--so no truth can be believed in, except under the peculiar measure of the believing individual mind. What a man adopts as true, and what he rejects as false, are conditioned alike by this limit: a limit not merely different in different individuals, but variable and frequently varying in the same individual. You cannot determine a dog, or a horse, or a child to believe in the Newtonian astronomy: you could not determine the