The conversation between Socrates and Thrasymachus in the Republic is of great significance when defining justice. I will explain the importance of this conversation between Socrates and Thrasymachus in Book One of Plato’s Republic. The vital part of Book One begins when Socrates asks Thrasymachus to define justice. In the Republic at 338b-c, he does so in saying “Justice is nothing other than what is advantageous for the stronger.” I’ll begin by explaining what Thrasymachus’ definition of justice means, and then get into the specifics on how Socrates deciphers, and successfully refutes it.
Thrasymachus explains that each city is ruled by rulers who make rules that are advantageous for themselves, which he calls just. In decoding Thrasymachus’ definition of justice, Socrates manages to destroy its credibility. Socrates begins by making clear what a craft is and what a craft’s purpose is by using the example of a doctor in relation to medicine. At 341e, Socrates says “To provide what is advantageous, that is what the craft was developed for.” So medicine was discovered not to be advantageous for medicine, but for the body because the body is deficient on its own. In saying this, Socrates is pointing out that a craft exists to be advantageous for what it deals with and not for its own advantage.
Medicine is a craft that rules over the body. By providing what the body lacks, medicine is stronger than the body. That is to say that a craft is stronger than what it rules over. A doctor judges what is good for his patient and not what is good for him. He or she does this because they possess the knowledge to do so. In possessing this knowledge, the doctor is stronger than the body he is treating. If a craft is stronger than what it rules over, and ruling is a cr ...