The Platonic conception of justice or Virtue on the one side, and of Injustice or Vice on the other, is self-regarding and prudential. Justice is in the mind a condition analogous to good health and strength in the body--(_mens sana in corpore sano_)--Injustice is a condition analogous to sickness, corruption, impotence, in the body.[16] The body is healthy, when each of its constituent parts performs its appropriate function: it is unhealthy, when there is failure in this respect, either defective working of any part, or interference of one part with the rest. So too in the just mind, each of its tripartite constituents performs its appropriate function--the rational mind directing and controuling, the energetic and appetitive minds obeying such controul. In the unjust mind, the case is opposite: Reason exercises no supremacy: Passion and Appetite, acting each for itself, are disorderly, reckless, exorbitant. To possess a healthy body is desirable for its consequences as a means towards other constituents of happiness; but it is still more desirable in itself, as an essential element of happiness _per se_, _i.e._, the negation of sickness, which would of itself make us miserable. On the other hand, an unhealthy or corrupt body is miserable by reason of its consequences, but still more miserable _per se_, even apart from consequences. In like manner, the just mind blesses the possessor twice: first and chiefly, as bringing to him happiness in itself--next also, as it leads to ulterior happy results:[17] the unjust mind is a curse to its possessor in itself, and apart from results--though it also leads to ulterior results which render it still more a curse to him. [Footnote 16: Plato, Republic, ix. p. 591 B, iv. p. 444 E.] [Footnote 17: Plato, Republic, ii. p. 367 C. [Greek: e)peidê\ ou)=n ô(molo/gêsas tô=n megi/stôn a)gathô=n ei)=nai dikaiosu/nên, a(\ tô=n te a)pobaino/ntôn a)p' au)tô=n e(/neka a)/xia kektê=sthai, _polu\ de\ ma=llon au)ta\ au(tô=n_], &c.]