One of the funniest things about reading the Great Books is that you learn what's actually in the text instead of what's supposed to be in it.
The best example here is Plato and Platonism. See, Platonism is essentially idealism: the notion that there exist perfect forms, and that reality is a reflection of these forms. For instance, there exists an ideal republic, and while all existing republics are flawed in various ways, they are praiseworthy to the extent that they mirror the ideal republic.
This idealism is a running theme within Plato, particularly in the later dialogues, and perhaps it is what Plato himself believed, but it was not regarded as being a core element of Platonism either in his own day or for the next eight hundred years.
Plato was the forefather of what we call Platonism (which is really Neoplatonism), but Stoicism, Epicureanism, Cynicism, and Skepticism are also fruits from the Platonic tree. And what all these share is that, with the exception of Skepticism, they are primarily moral philosophies: they are about how human beings ought to act in the world. The true genius of Plato (or perhaps Socrates, since it’s unknown what came from him and what came from Plato) was that he made human behavior his primary concern. The Pre-Socratics are best known for their theories about the nature of the universe (Thales thought all matter was ultimately water, while Anaximenes thought it was ultimately air, etc), but the Socrates in Plato’s early dialogues wasn’t that worried about this. He was concerned with the question "What is goodness?" and "What is virtue?" And early Greek philosophy split based on the answer to that question. Epicureans thought the aim of life was pleasure; Stoics thought the aim was to perfect yourself in virtue; Cynics thought all conventional desires--those in which humans differed from animals--were ultimately foolish and evil; and Skeptics thought it was impossible for people to know what was good.
The confusion continues when we add Aristotelianism to the mix. Aristotle was the preeminent philosopher in the Christian and Islamic world in the six hundred years after the Arab invasions. Plato was essentially unknown in both worlds. There are very practical reasons why, if you're only going to translate one author, it ought to be Aristotle. He was a collector, a magpie. When he examined a topic, he collected everything that was known about the topic, examined each argument, and tried to find a synthesis (while adding, at times, his own empirical researches). The vast majority of what we know about the state of knowledge in Classical Athens comes from Aristotle: he reported not just his own thoughts, but the thoughts of those he disagreed with.
In the medieval world, the method of Aristotle became just as influential as his teachings. The Scholastics thought that for every question, the answer must already be somewhere in the world, and they believed that by reconciling all the different views on a subject, and showing how they were the same (or at least non-contradictory) they could find the truth. It's a very careful, somewhat-empirical method.
So his method is very different from Plato's. Aristotle conducts a careful weighing and sifting of the evidence and a distrust of naked thought; Plato, on the other hand, engages in winner-take-all arguments. Platonic philosophy happens on the page. In Plato, there's no sense that, oh, Protagoras or Gorgias might have a piece of the truth: instead they simply get demolished by Socrates, who shows how their ideas are foolish. To the extent Plato has a method, it comes through the manipulation of language and concepts themselves: he shows how inherent in the way we use words, or use the concepts that words represent, there is a certain understanding of a thing's true nature. There is also a lot of argument by analogy in both Plato and Aristotle: this thing is akin to this other thing, therefore it ought to work how that other thing works, but in Aristotle the analogues are usually grounded by his scientific studies. He talks about specific phenomena he has observed or studied and how they might analogize to this situation, while in Plato the analogies tend to be more general. For instance, Plato might compare the Republic to a body, which has different parts, but Aristotle would go further and try to create linkages between the parts based on the linkages between the body: he might say “Blood goes to the stomach before it goes to the head, symbolizing that the farmers must be fed before the princes can eat”…etc.
So the methods are very different. But the content of Aristotelianism and Platonism are basically the same. They have similar visions of morality, similar political systems, similar metaphysics. Between the two there is very much a narcissism of small differences. So in The Politics, Aristotle goes on and on about the silliness of Plato’s Republic, and how it makes no sense to have a class of rulers who owns nothing, etc. But on a fundamental level, they agree that a republic should be ruled by its best men, rather than by the masses or by its richest men. Similarly, on the problem of universals, there are various fiddly differences, but they both believed that universals were real (an opinion whose opposite is nominalism, under which we derive the universal from the physical, and the universal isn't real, it's merely a name, an abstract concept, without an existence outside of language).
But in the Renaissance, the conflict between Plato and Aristotle was very real and bitter. The Renaissance humanists rediscovered Plato, using the translations made my Marsilio Ficino in the 15th century, and they used him as a club to batter the remaining scholastics. Over the course of three hundred years, the humanists took over the universities and displaced the scholastics. This resulted, first and foremost, in an alteration of method: Descarte's method is clearly much more Platonic than Aristotelian. It also allowed them to devalue Medieval learning--under Plato's method, it's a lot easier to simply dismiss a branch of learning than it is under Aristotle's.
So the primary difference in the two authors is in the quality of their thought. And if you read both authors, you will rapidly come to understand this difference, because it's in every work, it's in every dialogue. They reasoned in very different ways, even if their conclusions were rather similar.
But it's precisely this difference in their quality of thinking that is lost when the two philosophers are reduced to their content. To contrast Aristotelianism and Platonism in their content leads to playing up relatively small differences, mostly to the detriment of Aristotle--it leaves you wondering why we need the man at all, when he didn’t say anything that Plato didn’t say first.
To further complicate matters, both the content of the Aristotelian and Platonic systems derives less from their texts and more from the texts of their followers. Our conception of Aristotelianism comes from Averroes, the 12th century Muslim Andalusian who made it his life's work to figure out what exactly Aristotle had said on any given topic, writing extensive commentaries on many of Aristotle's works. Many early Latin translations of Aristotle are translations of the commentaries of Averroes (often from Arabic into Hebrew then Hebrew into Latin, over the course of several generations). Platonism on the other hand comes from the 3rd and 4th century Neoplatonists, most notably Plotinus, who gave a semi-mystical spin to Platonism and generated the notion that the universe was, essentially, a great mind that's coming to know itself--an idea that would percolate on down through to Hegel and the Continental philosophers.
If you learn about both writers, you're going to spend a lot of time learning about that very specific doctrinal stuff--you'll learn dogma, in other words. This is what Aristotle believed. This is what Plato believed. But you won't learn the most important thing about both authors, which is how they thought!
On the other hand, if you only read the primary sources, you'll have learned about their method, but you won't have learned most of the stuff I've written about in this blog post (which I largely learned through the History of Philosophy without any Gaps podcast). And that means when you talk about Plato and Aristotle, you'll come off like a buffoon.
For instance, you're most likely not going to read the later dialogues of Plato where his metaphysics are laid out. That means your understanding of Plato is going to be as the arch-skeptic--the demolisher of values. In fact, this is how he was understood in his own lifetime and in the years after. For hundreds of years after Plato's death, his Academy embraced skepticism: they believed that human knowledge had hard and unpassable limits. Both to his immediate successors and to the casual reader, Plato's writing is much more likely to lead to skepticism than to what we call Platonism. But if you say that Plato’s philosophy was inherently skeptical and had no determinate content, people will think you’re ill-educated. Your understanding is eminently defensible when it comes to the text itself, but it doesn’t account for the meaning that the centuries have imparted to the text.
This is one of the knocks against autodidacticism, which is that by only reading primary sources, you miss much of the context that surrounds an author. Maybe if I ever write another book on the Great Books I'll write an autodidact's crib sheet, which fills in all these little things.
But, personally, I think that an autodidact also has an advantage over the scholar and the student, in that the autodidact comes face to face with what made the author great and influential. Let's face it, Plato isn't influential because of the allegory of the cave: he's influential because of his style, his method of argumentation. And the best way to gain an understanding of that style is to read him for yourself. It's like going to a museum. If you look at the dinosaur bones without reading the descriptions, then you understand how immense a dinosaur can be, but you don't really know that they’re related to birds, they had feathers, etc. But if you only read the descriptions but never look at the bones, then what have you really learned? You haven’t understood the most fascinating thing about the dinosaurs, which is that they dwarfed all currently-living land animals. You've gained the context, but not the experience it's meant to contextualize.
Housekeeping Note:
The readership of this Substack was dwarfing that of my Wordpress, but it was difficult and confusing to maintain two sites simultaneously, so I shut down the Wordpress site and importing my approximately 1900 posts (going back to 2008) to Substack. They’re all behind the paywall, and I imagine it’s very hard to make any sense of them or properly navigate them, but they’re there, online for anyone who cares.
The illustration shows Plato (I assume, since he is the older-looking one) unarmed against a sword-wielding Aristotle. I'll place my bet on Aristotle, thank you. Maybe one day we will have the full text of some of his dialogues, highly esteemed in ancient times but known to us only in fragments.
Though rarely read today, about a quarter of Aristotle's surviving writings are on biology, a science he founded. Armand Leroi, a biologist, wrote a fascinating book called The Lagoon, based on spending months at the place where Aristotle conducted much of his biological research, looking for what Aristotle had seen.