Both Plato’s Republic and Friedrich Nietzsche’s On the Genealogy of Morals focus on morality; what are good and evil, right and wrong, justice and injustice. They each criticize the moralities of their respective societies, and propose an alternative in their works. The two philosophers have very different methodologies, and different ideas about what is moral, though. Plato’s philosophy is a search for universal truths and wisdom, which celebrates the ascetic philosopher and his quest to discover essential forms. Nietzsche’s philosophy rejects platonic forms, instead finding morality in the natural social order from which his society has tragically distanced itself. Although Christian morality is the main target of Nietzsche’s criticism, he would certainly also criticize Plato on several points. Two points where the philosophers clash are the source of morality, and the value of self-denial.
The first clash between Nietzsche and Plato is about the source of morality. Plato believes in “forms”, which are the absolute essence of ideas that exist outside of the natural world. “Goodness” is one such form. The form of goodness is supernatural, casting light on the physical world but itself apart from it. So a good person is brave, truthful, and patient, but none of those qualities are themselves a part of the form of goodness. It exists independently. The form of goodness is both supernatural and absolute; in the context of a city, a family, and an individual, the form of goodness looks the same.
In contrast, Nietzsche’s morality is neither supernaturally derived nor absolute. He identifies two types of morality, master morality and slave morality. Master morality is the morality of masters, the beasts of prey, who glorify the qualities of the powerful. Slave morality is the morality of the downtrodden, born from ugly ressentiment, which opposes master morality by telling the weak that they are nobler than the strong. But while he does argue that master morality is preferable to slave morality, there is no divine blessing or supernatural form of goodness making it inherently better. He sees Christian (slave) morality as vindictive, unnatural, and harmful to the spirit. Master morality is only superior because it does not stem from ressentiment and does not encourage painful sublimation of animal urges, not because it is closer to an absolute ideal of goodness or truth.
Nietzsche’s method provides morality-seekers with an alternative to traditional philosophy’s search for universal values. Nietzsche’s book is called On the Genealogy of Morals, and like the title says it takes a historical approach to the source of morality. At some point in history, master morality grew out of the ability of those in power to define the terms “good” and “bad”, and slave morality was a subversion of that power by the vengeful priestly classes. In that framework, the notion that a universally correct morality can be divined from a platonic form of goodness is unintelligible. All definitions of morality come from somewhere, and different people’s definitions came from their circumstances. This is a clear departure from earlier philosophy, and shows the incompatibility of Nietzsche’s naturalism with Plato’s supernaturalism.
The second clash between Plato and Nietzsche is how they view self-denial, especially in the context of the ascetic philosopher. In short, Plato sees self-control (in the form of self-denial) as one of the most important qualities of a moral man. Nietzsche would see this form of self-control as a tool of slave morality, and encourage instead that people use their willpower to achieve external goals.
Although Plato might not be a true ascetic, he does think that a correct understanding of morality requires discipline over one’s animal urges. Plato sees the soul as divided into three parts; in a well-organized soul, the reasoned part rules the spirited and appetitive parts. The man with the best knowledge of morality, the philosopher-king, will need a soul so well-organized that he craves nothing for his body, only truth and learning. For lesser men as well, their appetites must be ruled by reason for them to be moral (wise, courageous, temperate, and just). Therefore, even though Plato isn’t advocating a lifestyle of complete abnegation, he is claiming that moral men must have complete control over their animal urges.
Nietzsche’s response to this claim is cynical. His view is that philosophers like Plato glorify asceticism because it provides them with the conditions that are best-suited to philosophy. A philosopher can avoid marriage, money, outside disturbances, wander off into the desert to think and write, and then feel virtuous for it. Priests, who are really just masked philosophers, created the ascetic ideal for their own benefit. He isn’t explicitly saying that all self-denial is bad, but that the philosophers who praise it are just as self-serving as anyone else.
As an alternative, Nietzsche would suggest turning the energy that men use for bad conscience into a weapon against slave morality. Bad conscience is the guilt and torturous self-denial that comes from suppressing man’s animal instincts. He believes that the ascetic ideal is a natural, if maladaptive, response to bad conscience. But if society can turn away from slave morality’s self-denial and back to master morality, bad conscience will go away, and the ascetic ideal won’t serve any purpose. In this model, self-denial is a sickness which needs to be fought. Plato says that the soul in which appetite and spirit are ruled by reason will be the most harmonious and lead to a wise and just society; Nietzsche counters with the exact opposite.
Nietzsche, in Twilight of the Idols, calls Socrates “a buffoon who got himself taken seriously”. Considering that the context is his criticism of dialectics, the insult would most likely apply to Plato as well. Likewise, Plato would probably just dismiss Nietzsche in the same way he did Thrasymachus, as unfit for philosophy. And yet, they are alike in that their radical takes on morality have had a huge influence on philosophy that came after them. Plato’s supernaturalism and well-ordered soul and Nietzsche’s naturalism and master morality have both had a huge impact on the discussion around what it means to be moral, and that conversation is likely to continue for millennia to come.