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Plato and Solipsism

By Lee Morgan

Plato’s Republic begins with Socrates debating Thrasymachus. Their disagreement regards the essence of justice. Throughout the argument, Socrates presents an idealistic, egalitarian perspective. Though avoiding definitions, he insists that justice serves the whole community. But Thrasymachus disagrees. He asserts that “justice is nothing else than the interest of the stronger.” And while Plato favored his mentor’s idealism, both interlocutors present captivating arguments. And indeed the debate even ends in aporia; and for uncertainty at that!

From there continue the Republic‘s nine, remaining books. These present the Socratic conception of justice in allegory. But they all presume Thrasymachus to have been wrong. In this regard, these books make one massive if statement. If Thrasymachus was wrong, then books 2-9 depict justice. But Plato already shows that this ’if’ statement is impossible to prove. This is why book one ends how it does. But the Republic pushes past aporia, and turns to allegory for the same reason that religions do. Put simply, Plato did not take the limits of rational discourse for the limits of philosophy.

This theme repeats itself throughout Plato’s corpus. In his early works, he used aporia to highlight the limits of discourse without pushing past them. Lysis is an excellent example of this. There Plato ends his dialogue right when reason exhausts itself. But later in his corpus, Plato pushes further, applying esotericism to such problems. As a result, books like Parmenides and Philebus at times approach unintelligibility. In them he studies what he at first had left untouched: Essences. In turn, even professional, academic philosophers tend to struggle with these books. But Plato believed the difficulty was intrinsic to the material, and not his presentation.

But in what does this difficulty subside? Let us return to the Republic’s opening argument. The question of justice’s definition is an ontological one. But it raises an epistemological concern. If absolute definitions exist, can we know them? If Plato restricted knowledge to what reason could cognate, he would have answered no. Hence the aporia. Indeed the opening debate could not be won on its own terms. But why is that? Let us take a closer look.

To reiterate, the debate is about which sense of the word ‘justice’ is its true sense. Socrates asserts the a priori ideal of justice as fairness. But this a priori sense hardly resembles the practices of actual people and states. And herein lies Thrasymachus’ argument. Rejecting his opponent’s abstract principles, he argues with a posteriori evidence. Instead of principles, he looks to practices. And their findings could not differ more.

All considered, the former argues that what ought to be is, the latter that what appears to be is. But without already knowing what is, the argument is irresolvable. They might as well just state the two senses and go home.

Kant raises a similar question when postulating synthetic a priori propositions. He wondered whether questions about the ultimate nature of reality had answers. The trouble is that such answers would lie beyond both a priori and a posteriori reasoning. Take the definition of justice for example. What proof does Socrates provide? The best he can offer are axioms, but these axioms cannot prove themselves. We would already have to know their truth-value to know if they were true. But what about Thrasymachus? He can offer us pragmatism but nothing more. But I hear a scientist objecting! ‘But the truth of a posteriori reasoning lies in its utility!’ ‘What does that have to do with the veracity of a claim?’ ‘But it’s useful?’ ‘And why does utility matter?’ ‘Because it’s useful!’ The alternate response would be that such statements are reproducible. But provided we assume Socrates’ same axioms, we will reach his same conclusions. So not even in utility does one position discredit the other. For neither position can step outside itself without first presuming an answer.

But where does Plato figure into this? Well if we believe him, he can perceive synthetic a posteriori facts. How else would one describe his intuiting the form of the Good? Parmenides? His unwritten doctrine? But could he intuit everything he claimed to? Could he intuit anything at all? The question is unanswerable for the same reason that we cannot define justice. Plato’s philosophy is in its heart irrational. But that does not mean it is untrue. It only means that we cannot determine its truth-value because it lacks one. And what lacks truth-value cannot be wrong. But let us consider the consequences.

What if Plato’s famous distrust of rhetoric better pertains to discourse in general. Look to Euthydemus for example. His frustration is on full display there. And why else than because the sophists have reduced philosophy to idle discourse? And what about poetry? Does not the poet present reality as he understands it without reference to its essential nature? Is this not why Plato disliked Homer’s depiction of the gods? It seems that we must understand Plato as a mystic of irrational revelations, rather than as a rationalist.

But what does this have to do with solipsism? Does Plato not claim to know the absolute nature of reality? The answer depends on how we understand the question, and reality for that matter. As we have already discussed, Plato believed he could intuit essences. But he did not claim to know them, hence his reluctance to commit his true perceptions to writing.

Plato knew his observations different from ordinary judgments. This is why he does not outright define justice in his Republic. Recall how the opening debate ends in aporia. This is intentional, for Plato knows the limits of discourse. Thus he does not argue his point through dialectic. But like a prophet, he shows the truth without saying it. Hence his dependence on allegories. In relation to solipsism, Plato is like an honest face-reader. He knows his art is unscientific and does not tell us what he sees. But he still sees it, and hints at it, as he believes in its truth.

But isn’t solipsism relativistic? And didn’t Plato hate relativism? He disagreed with Protagoras didn’t he? With regard to solipsism, only varying types of judgments are relative to each other, i.e. a priori statements are relative a posteriori statements. But judgments of a certain type have firm conclusions, i.e. Caesar did or did not cross the Rubicon. There is no relativity there. Likewise, subjective judgments also have firm conclusions. For example, artistic judgments are subjective, but still rely on principles or values. If two judgers share the same criteria when judging a piece, their conclusions will be the same. Such judgments are only relative to judgments made with reference to unlike metrics. Just read Euthydemus. There Plato limits himself to a priori judgments. And he still proves that the sophists are being irrational. Likewise, Socrates and Thrasymachus could have debated the merits of each other’s sense of justice. If they had restricted their discussion to whether Socrates’ justice was truly idealistic, or where Thrasymachus was actually describing how justice is practiced, they could have arrived at firm conclusions. But these sorts of questions never interested Plato, certainly not like his private observations did.

So was Plato a solipsist? Again the answer depends on how one understands the question. It is clear that he preferred his intuitions to proper judgments, as it is that he knew the limits of said judgments. Likewise he could clearly appreciate the truth in opposed worldviews, i.e. Heraclitus and Parmenides. But like Ryan Smith notes, his thought is hierarchical. Plato was not content to identify the dividing line. He ordered it, creating a spiritual itinerary of sorts. But his itinerary was a mere reflection of his own being. And indeed he only shared his deepest convictions with people who were similar, or had modeled themselves after himself, i.e. his theoretical philosopher king. Was he a solipsist? It depends on your definition.

Published in Lee Morgan