What I say here applies especially to the Protagoras: for I am well aware that in other dialogues the Platonic Sokrates is made to hold different language.[217] But in the Protagoras he defends a theory the same as that of Aristippus, and defends it by an elaborate argument which silences the objections of the Sophist Protagoras; who at first will not admit the unqualified identity of the pleasurable, judiciously estimated and selected, with the good. The general and comprehensive manner in which Plato conceives and expounds the theory, is probably one evidence of his superior philosophical aptitude as compared with Aristippus and his other contemporaries. He enunciates, side by side, and with equal distinctness, the two conditions requisite for his theory of life. 1. The calculating or measuring art. 2. A description of the items to which alone such measurement must be applied--pleasures and pains.--These two together make the full theory. In other dialogues Plato insists equally upon the necessity of knowledge or calculating prudence: but then he is not equally distinct in specifying the items to which such prudence or calculation is to be applied. On the other hand, it is quite possible that Aristippus, in laying out the same theory, may have dwelt with peculiar emphasis upon the other element in the theory: _i.e._ that while expressly insisting upon pleasures and pains, as the only data to be compared, he may have tacitly assumed the comparing or calculating intelligence, as if it were understood by itself, and did not require to be formally proclaimed. [Footnote 217: See chapters xxiii., xxiv.,** xxxii. of the present work, in which I enter more fully into the differences between the Protagoras, Gorgias, and Philêbus, in respect to this point. Aristippus agrees with the Platonic Sokrates in the Protagoras, as to the general theory of life respecting pleasure and pain. He agrees with the Platonic Sokrates _in the Gorgias_ (see pp. 500-515), in keeping aloof from active political life. [Greek: a\ au(tou= pra/ttein, kai\ ou) polupragmonei=n e)n tô=| bi/ô|]--which Sokrates, in the Gorgias (p. 526 C), proclaims as the conduct of the true philosopher, proclaimed with equal emphasis by Aristippus. Compare the Platonic Apology, p. 31 D-E.] [Side-note: Distinction to be made between a general theory--and the particular application of it made by the theorist to his own tastes and circumstances.]