For Thucydides the goods of effectiveness always trump the goods of excellence. Excellence will only carry the day insofar as the powerful decide that it is in their interest to do so toward effective ends.
It is against this stance that the mature Plato argues. For Plato there can be no justice or rationality apart from the virtue of pursuing the greatest goods of excellence. What are these goods? For Plato they can be arrived at through dialectics until one reaches a proposition concerning the Good that is irrefutable. Thus justice is an ideal toward which Socrates and his interlocutors debate in the Republic. Particular virtues pursued toward their ultimate ends is what constitutes the various goods of excellence. These goods are ideals that are irrefutably excellent to all rational beings in all times and places. Goods are universal and are to be pursued independent of reference to human wants, preferences or satisfactions which are the criteria of goods of effectiveness.
Not so! Say the sophists. There are no goods independent of or prior to wants, preferences or satisfactions and there is no God’s-eye universal view from which humanity can discern what the ultimate goods of excellence truly are for all people in all places and at all times. For sophists, a Platonic pursuit of goods of excellence is a fool’s errand.
The dispute between Plato and the sophists largely shapes the debate over the demands of justice and practical rationality to this day. The key question is whether or not there are goods that are prior to and independent of human wants, satisfactions, or preferences. How one answers that question will determine how one understand the demands of justice and practical rationality, whether they make reference to universal goods that all people ought to pursue no matter what the personal cost, or whether or not justice and rationality are really ways of talking about what seems to work best so that the greatest number of people get what they want.
For Plato progress when it comes to uncovering the ultimate goods is an incomplete task, but one that advances ever onward toward the ultimate logos. For the sophists, progress in human understanding can be made, but there will never be a destination at which we can arrive and say, “at last! We have finally discovered the Truth about (say) the demands of Justice!” Plato thinks that dialectics will lead us out of the cave into the realm of Forms, sophists think that there’s only the cave and we’d better make the best of it in here for the greatest number of people. Plato will say that justice looks the same for everyone: Athenians, Spartans, Americans, South Africans, and Australians alike. The sophists will say that justice looks different for each of those groups because there is no Justice, only justices which are really what seem like the best arrangements for those particular groups of people.
Plato offered not a solution to the debate between goods of excellence and those of effectiveness, but he bequeathed the world a dilemma that has shaped the dialogue henceforth: can we ever arrive at the goods of excellence? Or must we settle for goods of effectiveness?
If the sophists are right – as perhaps most people today hold – then the question becomes how do we get people to pursue the goods of effectiveness as we define them? The answer is one offered by the heir of the Periclean tradition, Isocrates. For Isocrates the dialectical debate over the goods of excellence was abstruse and even a dangerous distraction from the practical demands of political life. Who has time to argue over the demands of a pure justice when the Persians are at the gates? Isocrates prioritized rhetoric is his scheme of education, because it wasn’t a pursuit of some unattainable understanding of pure, universal truths that mattered most but the needs of the city-state. What the city-state needed was unity in order to conquer her enemies, that unity couldn’t be achieved through philosophy but through rhetoric which appealed not the reason of the citizenry but to their passions. Thus, sophistry seems to inevitably lead to the privileging of the emotional over the rational, pathos over logos. Rhetoric under this scheme doesn’t serve truth but creates it. For the sophist truth isn’t formal but perspectival and infinitely malleable.