In Plato's Republic, what is Plato’s notion of justice through Socrates how does it conflict with that of Thrasymachus?
Thrasymachus's view of justice is one where power is the ultimate metric. Thrasymachus views justice in the most temporal of terms, where individuals are able to exert power through any possible means. Thrasymachus suggests that “justice is . . . the advantage of the established rule" and that "Justice is nothing other than the advantage of the stronger." Thrasymachus argues that power is the defining element behind justice. Governments that pursue the ends of justice do so as a means and justification of their power. For Thrasymachus, the definition of justice is one that is inseparable with power. As a result, he further contends that true freedom exists with injustice, denigrating justice as an end to individual pursuit when he argues that injustice is "mightier, freer, and more masterful than justice." Thrasymachus's position asserts that “A just man always gets less than an unjust one." The idea of reciprocity in an extrinsic understanding is where his vision of justice lies. In this analysis, Thrasymachus defines justice in external and temporal notions of the good.
Socrates defeats this through his own position that holds justice as its own intrinsic good. Socrates argues that justice is not extrinisic and not external. Rather, it is a reflection of the highest essence of the good. Socrates argues that “[N]o one in any position of rule, insofar as he is a ruler, seeks or
orders what is advantageous to himself, but what is advantageous to his subjects; the ones of whom he himself is the craftsman.” This helps to establish that justice is not representative of "might makes right." Rather, it is a skill, no different than the refinement of a master craftsman who focuses on a vocation or particular calling. It is something that must be within the individual and practiced with the utmost devotion. Socrates will later argue that justice is this way because it is a form, an example of the highest notion of the good. Individual actions are aligned with this universal essence and, for this reason, justice is something that individuals must embrace and understand both as skill and as extensions of themselves. Socrates's position regarding justice views it as something within the individual and embodying of an higher calling: “No craft or rule provides for its own advantage, but . . . for its subject and aims at its advantage, that of the weaker, not of the stronger. That’s why...no one willingly chooses to rule." The idea of internal duty is essential to the Socratic notion of justice, one that embraces an essence that defines consciousness. It is not extrinsic and material based, as Thrasymachyus has defined it. Rather, it is internal and something that the individual must acknowledge as such.
It is in this regard where there is a fundamental difference between Thrasymachus and Socrates in their construction of justice. Thrasymachus sees it in external and temporal terms. Socrates sees it one of universality and internal understanding where the individual willingly aligns themselves with this universal essence of being.