Episode 347 - If You Think True And False Are Impossible To Find, Then Don't Talk To Me About True And False
Welcome to Episode 347 of Lucretius Today. This is a podcast dedicated to the poet Lucretius, who wrote “On The Nature of Things,” the most complete presentation of Epicurean philosophy left to us from the ancient world. Each week we walk you through the Epicurean texts, and we discuss how Epicurean philosophy can apply to you today. If you find the Epicurean worldview attractive, we invite you to join us in the study of Epicurus at EpicureanFriends.com, where we discuss this and all of our podcast episodes.
This week we are continuing our series reviewing Cicero’s “Academic Questions” from an Epicurean perspective, which gives us an overview of the issues that split Plato’s Academy and helps us understand Epicurus’ position on the same issues. This week will continue in Section 13 of Book Two.
Our text will come from
Cicero - Academic Questions - Yonge We’ll likely stick with Yonge primarily, but we’ll also refer to the Rackham translation here: Cicero On Nature Of Gods Academica Loeb Rackham : Free Download, Borrow, and Streaming : Internet Archive
Summary
Section titled “Summary”Continuing Book Two of Cicero’s Academic Questions, Cassius and Joshua finish Section 13 and move into Section 14, where Lucullus turns to attack the skeptics’ method of division (diaeresis) — the Platonic technique, traced to Plato’s dialogues Phaedrus, Sophist, Statesman, and Philebus, of repeatedly splitting a broad concept into narrower sub-concepts until arriving at a definition. Joshua connects this to Cicero’s earlier complaint, in Book One of On Ends, that Epicurus is entirely destitute of logic, definition, and division, and reads a Wikipedia account crediting faulty diaeresis, per Galen, as the principal cause of most physicians’ medical errors. Cassius argues that neither division nor its inverse, addition — the method behind the Sorites “heap” paradox — can by itself deliver a stopping point or a criterion of truth; only the senses, anticipations, and feelings can tell you when you’ve gone far enough, a point he extends to modern line-drawing disputes over immigration, abortion, and end-of-life decisions. Reading from Rackham, Joshua presents Lucullus’ central counter-argument against the skeptics: that a definition, once granted to be true, cannot also apply to a false object, so if the skeptics let their own definitions do any work at all, they’ve implicitly admitted that true and false presentations can be distinguished. Cassius connects this to Epicurus’ broader method of turning a position back on itself — the same self-contradiction he finds in hard determinism, where a determinist’s own act of arguing already presupposes the freedom to persuade. Joshua closes with Diogenes the Cynic’s famous reply to Plato’s definition of man as a “featherless biped” — plucking a chicken and presenting it to the Academy — as a concrete illustration of exactly the failure Lucullus describes, and suggests that Cicero’s charge that Epicurus is destitute of logic and division may not be such a bad thing after all.
Transcript
Section titled “Transcript”Cassius:
Welcome to Episode 347 of Lucretius Today. This is a podcast dedicated to the poet Lucretius, who wrote On the Nature of Things, the most complete presentation of Epicurean philosophy left to us from the ancient world. Each week we walk you through the Epicurean text, and we discuss how Epicurean philosophy can apply to you today. If you find the Epicurean worldview attractive, we invite you to join us in the study of Epicurus at EpicureanFriends.com, where we discuss this and all of our podcast episodes.
This week we’re returning to Cicero’s Academic Questions, and we’re in Section 13 of Book Two, where the Stoic Lucullus is about to attack the skeptical position against the possibility of knowledge. We’ve been in this for several weeks now. We’re probably going to finish it today and move further into Lucullus’ argument. But the basic foundation of where we are at the moment is that Lucullus has set out the skeptic argument, which comes down to the contention that it is impossible to distinguish true sensations from false sensations. That’s part of what we’re going to discuss today, because Lucullus, the Stoic, is going to attempt to turn the skeptic’s argument back against their own conclusion.
The ins and outs of the logical debate can become maddening to try to follow, which is to some extent why Epicurus denied the necessity of arguing things such as the desirability of pleasure or the undesirability of pain through logical argument, rather than simply relying on what the senses present to you. As we’ve said many times, there are incredibly important practical implications to the argument that we’re discussing. And you can’t let obsession over the minuteness of every limb and every leaf on every tree confuse you into thinking that there’s no such thing as a forest, into thinking that forests don’t exist, because there are important conclusions that you have to make in your life in order to succeed, and you cannot spend every moment of your life subdividing and subdividing and subdividing every argument down into something that you can identify and write a formula about on a piece of paper.
It’s sort of an analogy with the atoms. You cannot subdivide atoms infinitely. What Epicurus is focusing on in regard to atoms is not that an atom is what we think of today as protons and electrons. The essential point of Epicurus was that you cannot subdivide and subdivide and subdivide infinitely. With the atoms, it makes no sense to do so, or else you would have no regularity of the universe, and none of the physical processes that we see would make sense. With argument about ethics and logic, you’ve got a similar barrier. You have to live your life and reach conclusions, regardless of any desire you might have to divide and divide and divide and divide the argument and lay it out in formulas. At some point, the subdivision has to stop and you have to live your life. And where that subdivision stops is, in part, what we’ll be discussing today.
So, Joshua, where do you think we left 13? And bring us up to speed as we begin to move into 14.
Joshua:
We are desperately trying to get away from this syllogism, but we are still following up on it. So let me just very briefly explain again what the syllogism is. Two objects entirely alike present the same appearance, but so also do two objects only superficially alike, though not really alike entirely. They are indistinguishable by the senses. We might think that a particular appearance or representation is attributable to one of the objects, but since it is indistinguishable from the other appearance or representation, it might come from either. And the point is, we don’t know. And it is on this ground that they determine perception to be impossible, and with perception, all knowledge. And this is where you get people like Socrates saying, “All that I know is that I know nothing,” and so on.
Now, we followed up on that syllogism last week with the discussion of the premises that Lucullus says go into the syllogism. He mentions two premises: first, that false presentations cannot be perceived, and second, that if presentations have no difference between them, it is impossible that some should be such as to be capable of being perceived, and others such as to be incapable. And that brings us to the remainder of 13, which I don’t think we’ve read yet.
In the remainder of 13, Lucullus talks about the further propositions that are not axiomatic, but that the skeptics defend with a long and varied discourse, as he says. These propositions are also two: first, that of the objects of presentation, some are true, others false; second, that every presentation arising from a true object is of such a nature that it could also arise from a false object. These two propositions, he says, they do not skim over, but develop with a considerable application of care and industry. They divide these propositions into sections of wide extent — first, sensations; next, inferences from sensations and from general experience, which they deem to lack clarity. Then they come to the section proving the impossibility of perceiving anything, even by means of reasoning and inference. These general propositions they cut up into still smaller divisions, employing the same method with all the other topics as they do with sensation, aiming at proving, in the case of each subject minutely subdivided, that all true presentations are coupled with false ones in no way differing from the true, and that this being the nature of sense presentations, to comprehend them — indeed, to comprehend any of them — is impossible.
So that, which I’ve very briefly gone through there, is the end of 13. And 14, which we will probably spend most of our time on today, I would think, is Lucullus’ response to the syllogism, the axioms that went into it, and the propositions which they defend using the tools of logic adopted from Plato.
Now, in what we just read in 13, and in what we’re going to be going into today in 14, we are talking a lot about this word division. And we first encountered this term, I think, on the podcast, Cassius, back when we went through another work of Cicero’s. This was On Ends, De Finibus Bonorum et Malorum, on the ends of good and evil. And in the introductory matter, the first book of that text, the book that contains Torquatus’ presentation of Epicurean ethics, Cicero is invited at the very beginning to give his brief criticisms of Epicurus. First he talks about physics, or natural philosophy, or whatever you want to call it, and he says that Epicurus just copies Democritus, and where he differs from Democritus, he’s always more wrong than Democritus — worse than Democritus even when he’s differing from him, though he claimed not to be influenced at all by Democritus, and so on. Then we get to the second division of philosophy, which he calls the department of method and of dialectic, which is termed logic.
“Of the whole armor of logic, your founder, Epicurus, as it seems to me, is absolutely destitute. He does away with definition. He has no doctrine of division or partition. He gives no rules for deduction or syllogistic inference, and imparts no method for resolving dilemmas or for detecting fallacies of equivocation. The criteria of reality he places in sensation. Once let the senses accept as true something that is false, and every possible criterion of truth and falsehood seems to him to be immediately destroyed.”
And I don’t think at the time, Cassius, I had a very deep understanding of what he was talking about here. I knew partially from Norman DeWitt that Epicurus didn’t spend much time with definition, and that he says in the letter to Herodotus that we must grasp the meaning commonly attached to words rather than go on defining endlessly and never getting anywhere. But this question of division and partition, like deduction and syllogistic inference, which he also mentions, and methods for resolving dilemmas or for detecting fallacies, finds its first flourishing in the writing of Plato. And in Plato’s dialogues, the word in Greek that is used for division is diaeresis.
And Wikipedia says that diaeresis is “a form of classification used in ancient, especially Platonic, logic that serves to systematize concepts and come to definitions.” So that’s the whole project of this — we’re trying to divide broader terms down into their minute elements, and in doing so, we’re going to come to a definition, a workable definition, and a better understanding of each minute element.
“When defining a concept using diaeresis, one starts with a broad concept, then divides this into two or more specific sub-concepts, and then this procedure is repeated until a definition of the desired concept is reached.” Aristotle, it goes on to say, makes extensive use of diaeresis in categorization as a basis for syllogizing. “Diaeresis is Plato’s later method of definition based on division, developed in the dialogues Phaedrus, Sophist, Statesman, and Philebus. Further applications are found in the Laws and Timaeus. It is a means of attempting to reach a definition by which a collection of candidates is repeatedly divided into two parts, with one part eliminated until a suitable definition is discovered.”
And it gives an example from the Sophist, in which the Eleatic stranger in that dialogue is examining the problem of illusions, which consist of words and visual objects. Using diaeresis, he divides visual objects — by which it becomes clear he means works of art — into two categories: the art of making likenesses, and the art of creating illusionary appearances. The stranger is much more fond of the former. The latter is only created to produce an appearance of beauty.
And as we go further in the text, we are going to find more paradoxes and more problems that are going to invite, in the ancient mind, comparable methods. And one of these is the Sorites syllogism — the question of, you’ve got a number of grains of sand, or whatever, that form a heap. Where exactly is the precise boundary between a heap and not a heap? It’s the same kind of question. And so this is what we’re talking about in Platonic logic. This is what Cicero complains, in On Ends, that Epicurus himself is destitute in. This is what Lucullus is going to be confronting as we move into Section 14 today.
One more thing I wanted to point out from the Wikipedia page, which is somewhat interesting, is this: “Diaeresis is central to Galen’s therapeutics, where Galen, attributing the method to Plato, asserts that the errors of the medical sect, and whatever mistakes the majority of physicians make in the care of the sick, have incompetent division or diaeresis as their principal and major cause.”
And so this is not a theoretical question. This is not a logical question. This is not a question of how many angels can dance on the head of a pin. Galen, one of the foremost medical minds in the ancient world, is saying that diaeresis has very specific applications to life-saving treatments, and that ignorance of diaeresis is the main cause of medical mistakes. Now, I am not endorsing his claim — we know far more about medicine than Galen did, or anyone else in the ancient world did. But this is a clear example of where this crosses from the merely intellectual into the critically practical. And so, for that reason, it is, I think, worth discussion.
Cassius:
Joshua, it absolutely is worth discussion. And I think we’re going to get a much clearer picture of this the further we go. But already, I think I could suggest a particular question that needs to be asked here, in regard to whichever direction you come from — whether you go downward by division, or whether you go upward by the Sorites. What we’re looking for, apparently, and from their own profession, is a boundary. We’re looking at boundaries as an effort to help us arrive at truth.
And at least at the moment, what appears to me to be the question I would ask, from an Epicurean standpoint, is: no matter how far you divide, no matter how much you add, is it really only the process of division or the process of addition that leads you to a correct conclusion? No matter how deep you go, no matter how far up the ladder you go, there still is going to be the need to say, at this point, we have found our answer. And it seems to me that, logically speaking, simply dividing and dividing and dividing is not going to be any more helpful to you than adding and adding and adding is. At some point, you have to come to a conclusion that you have gone far enough. And what is going far enough tied to? It’s not simply tied to division, and it’s not simply tied to addition. I think, from an Epicurean point of view, you are first, last, and always looking at what the senses are telling you your reality is. You can divide and divide and divide, or you can add and add and add, but at every step along the way, it’s what your senses are revealing about that step in the process that is the key.
So, by no means do I have a fully developed comment on division versus addition. Cicero is very pleased, apparently, with the idea of division, and he’s very displeased with the idea of addition, in the sense of the Sorites syllogism, which we’re going to come to in just a couple of sections. The Stoic Lucullus is going to condemn the Sorites, and I think we’ll find that that’s Cicero’s own position as well, based on comments he’s made in other works. But in either case, division or addition, the logical process never stops. What you’re looking for is the place to stop. So it seems to me that’s a pretty good indication that the ultimate criterion of choice is not division or addition.
So, anyway, at this moment, Joshua, that’s just an unformed and uncompleted thought, but I think it does relate to what we’re talking about, and I think we’ll see more as we go into 14. So, when you’re ready, let’s go into Section 14.
Joshua:
Yeah, without dwelling on it, I just want to make a point quickly in response to your proposition that it’s not about dividing and dividing and dividing — eventually you have to come to a stopping point and say, here’s the line. So many of the cases in which this kind of logic, or this kind of reflection, affects us in our real lives is when you have two people, or two groups of people, or two political parties arguing about where exactly these lines are. And so just telling people, well, pick a spot and go with it — that’s just not going to work.
If you think about our modern arguments over immigration and borders, and what constitutes a nation, and which particular grouping you’re considering to be part of that nation, and someone else is saying we can actually expand that to include more, and some other third person is saying, no, we need to divide it even further and come to a more specific, more minute definition of what a nation is — and somehow, in all of this, we’re going to find the moral clarity to articulate the right policy. I think in a lot of these arguments there is a tendency to use this kind of language to mask what is a personal opinion that’s already been formed well in advance. I just want to point out that these issues are not far from our minds, even today, and even in very practical questions.
Cassius:
Joshua, absolutely right. And we will probably moderate how far we go into political issues, but you can certainly see the same questions at both ends of the life spectrum — both in the issues of abortion and end-of-life decisions. The incremental point at which you say this is okay versus this is not okay is not solved by simply logically dividing things up or adding things up. Addition and subtraction are not going to lead you to moral clarity. You use the term personal preferences, and yes, I think that in the end is absolutely the direction you’re going in — you clarify in your mind as best you can what the choice options are, and then you go with what your senses, anticipations, and feelings ultimately guide you toward in terms of pleasure and pain.
Joshua:
Yeah, I think that’s right. And I think that when we get into Section 14 here, which I’m about to read, we’re going to find that Lucullus has a different line of attack against the application of division to this particular syllogism, and to this particular claim that sensation or perception is impossible. Let’s move into that so we can explore what his view of this question is. We are still reading, by the way, from the Rackham translation — I’m on page 521 of the Loeb edition of this text on archive.org, in Section 14 of Book Two of Academic Questions.
“In my own judgment,” he says, “this minuteness, although no doubt highly worthy of philosophy, is at the same time absolutely remote from the position of the authors of this line of argument. For definitions and partitions and language employing schematics of this class, as also comparisons and distinctions and their subtle and minute classification, are the weapons of persons who are confident that the doctrines they are defending are true and established and certain, none of those who loudly proclaim that they are no more true than false.”
I guess that is very similar to the point we were just discussing, which is that people come into it with preconceptions and with their own opinions, and that they’re dressing it up in fancy Platonic logic in order to sell it more easily. He’s kind of making the same point, I think.
He continues: “For what would they do if, when they have defined something, somebody were to ask them whether that particular definition can be carried over to any other thing you like? If they say it can, what proof could they put forward that the definition is true? If they say it cannot, they would have to admit that, since even this true definition cannot be applied to a false object, the object explained by the definition can be perceived, and this they will not allow at any price. This same argument it will be possible to employ at every section of the discussion. For if they say that they can see through the matters that they are discussing with complete clearness, and are not hampered by any overlapping of presentations, they will confess that they can comprehend them. But if they maintain that true presentations cannot be distinguished from false ones, how will they be able to advance any further? For they will be met as they were met before, since valid inference is not possible unless you accept the propositions taken as premises as so fully proved that there cannot possibly be any false propositions that resemble them. Therefore, if a process of reasoning that has carried through its procedure on the basis of things grasped and perceived arrives at the conclusion that nothing can be grasped, what more self-destructive argument could be discovered? And when the very nature of accurate discourse professes the intention of revealing something that is not apparent, and of employing sensations and manifest presentations to facilitate the attainment of this result, what are we to make of the language of these thinkers, who hold that everything does not so much exist as merely seem to exist? But they are most completely refuted when they assume as mutually consistent these two propositions that are so violently discrepant: first, that some presentations are false, a view that clearly implies that some are true, and then, in the same breath, that there is no difference between false presentations and true ones. But your first assumption implied that there is a difference. Thus your major premise and your minor are inconsistent with one another. But let us advance further, and proceed in such a manner as not to appear to have been unduly partial to our own views, and let us go through the doctrines of these thinkers so thoroughly as to leave nothing passed over. First, then, what we have termed perspicuity has sufficient force of itself to indicate to us things that are as they are.”
Let me interject here to point out that this is a reference back to something that Lucullus explained in his presentation of Stoic epistemology, which was that sometimes, for some objects under certain conditions, the presentation of a particular appearance from that object is so clear, so perspicuous, that there is to be no doubt about it. This is a key part of his presentation of Stoic epistemology. So when he says, “What we have termed perspicuity has sufficient force of itself to indicate to us things that are as they are,” he is reiterating one of Stoicism’s central premises.
But nevertheless, he continues, “so that we may abide by things that are perspicuous with more firmness and constancy, we require some further exercise of method or of attention, to save ourselves from being dislodged by trickeries and captious arguments from positions that are clear in themselves. For Epicurus, who desired to come to the relief of the errors that appear to upset our power of knowing the truth, and who said that the separation of opinion from perspicuous truth was the function of the wise man, carried matters no further, for he entirely failed to do away with the error connected with mere opinion.”
It is a long and quite dense section, and no doubt presents difficulties of its own, but we do get a pretty clear glimpse of his central counter-argument to the skeptics, which is what he wrote in the first paragraph of the section. What, he asks, would they do if, when they have defined something, somebody were to ask them whether that particular definition can be carried over to any other thing you like? If they say it can, what proof could they put forward that the definition is true? If they say it cannot, they would have to admit that, since even this true definition cannot be applied to a false object, the object explained by the definition can, in fact, be perceived. And this they will not allow at any price, he says. But this is the key point that he considers to unravel their whole argument.
On what grounds should we determine this process of definition and division to be authoritative? It would be an assumption to say that the definition is true unless you’ve demonstrated the definition to be true, or to have a direct and real relationship with the particular object. And they’ve already stated that this kind of knowledge is precisely what they are claiming is impossible. Even if the definition is true — a true definition cannot be applied to a false object, or a false appearance from an object — then the object explained by the definition can be perceived. And so we have a paradox. They’re saying we cannot perceive or know, but we have this definition. The definition is a reliable guide in logic. A true definition can’t be applied to a false object. You have to know whether the appearance of the object is true or false to know whether the definition applies to it in the first place. I think that’s key to his argument, and sets off, here at the beginning of Section 14, his broader attack on this syllogism and on the labor and industry, as he says, that they use to prop it up.
Cassius:
Joshua, I agree with you that that is his chief argument. And rather than go further into 14 to additional arguments, I think this is where we ought to stop for today, to bring out the implications of this argument and really set it in our minds. Because, as you’re saying, Lucullus is pointing out that the skeptics are talking about similarities and dissimilarities. They’re using division to talk about truth and falsity, but that kind of argument, quote, “belongs to men” — and I’m reading Yonge here — “who are confident that those arguments which they are upholding are true and firm and certain, and not to men who assert loudly that those things are no more true than false.”
In other words, and this is the really key point, because this is a method of argument that Epicurus himself uses over and over, not only in regard to skepticism, but also in regard to determinism: if you’re going to take a position that truth and falsity are impossible to determine, then don’t talk to me about truth and falsity, because you’re saying you don’t know what you’re talking about. You are being totally inconsistent and self-contradictory to talk about truth and falsity, and to tell me that certain things are true and certain things are false, when you don’t know what true and false is. If you think you know what true and false is, then there is a method of determining what true and false is. And so you’re lying, or being a deceiver, or just plain stupid, in trying to argue this position to me.
And it’s the same argument Epicurus makes about necessity and determinism. Because if everything is necessitated by fate, by the universe, by the billiard-ball type of mechanistic determinism that those philosophers assert, then it makes no sense for you to be arguing with me that I should believe or not believe in determinism, because your argument and my response are all set from the beginning of time by this hard determinism. It’s inconsistent and self-contradictory to take a position and then argue as if you’ve ignored your own position. You’re saying truth and falsity don’t exist — well, then don’t talk to me about truth and falsity. You’re saying that there is no freedom whatsoever because everything is necessitated — then don’t talk to me about freedom or necessity, because it’s all a moot point that doesn’t even need to be discussed. And yet you’re discussing it with me, skeptics. You’re trying to tell me there is no difference between true and false. And you determinists are trying to tell me that I have no choices in my life whatsoever. “Fool me once, shame on you. Fool me twice, shame on me,” is something that applies here. These arguments are not in good faith from an Epicurean perspective, because they are self-contradictory.
Again, people like Cicero tend to minimize Epicurus’ concern about logic. But Epicurus is concerned about logic as much as anyone else is. He’s not going to let logic be used against the senses, to overthrow the senses, the things that nature gives to us. Logic is a wonderful tool to use when it is being used consistently with nature, and to understand nature in a way that is consistent with nature. But when logic is used to try to overturn nature, it’s a very destructive tool that needs to be rejected. And perhaps the first and initial way to decide whether a logical argument is being used productively and constructively is whether it is self-contradictory, because if it is, it needs to be discarded.
It’s kind of funny here the way 14 starts out, when he talks about the subtlety of division. Lucullus says, “Now, all this subtlety I consider indeed thoroughly worthy of philosophy” — that’s the Yonge translation — and Rackham has it as, “In my own judgment, this minuteness, although no doubt highly worthy of philosophy, is at the same time absolutely remote from the position of the authors.” Lucullus is trying to save arguments from minute divisions by saying, you’re just not applying it correctly, to the skeptics — almost like the arguments about communism, where the communists are always saying, you’re not applying communism correctly; it would be much better if you applied it correctly. Well, the Stoics, like Lucullus, attempt to rehabilitate arguments from division by saying they can be used correctly. And I think that’s going to be a difference of conclusion that we reach about Epicurus. Epicurus is going to say neither division nor addition are going to get you where you want to be. Nothing gets you to where you want to be except the faculties given by nature — the five senses, the anticipations, and the feelings of pleasure and pain. Those are the foundations for judging what is true and false. Those are the basis by which we decide that certain things are true and certain things are false.
So there’s a whole lot more in 14 to talk about before we move past this first initial division that you’ve brought up already, Joshua. Again, we probably ought to focus on this initial opening today in the interest of time. But what further thoughts do you have as we begin to come to a conclusion for today?
Joshua:
Well, I think you’re right to point out Lucullus’ deference to the methods of Platonism, which he considers to be a worthy pursuit in philosophy — this discussion of subdivision into minuteness. This reveals to us that Lucullus, like Cicero, also has one foot in each camp. Cicero is full of admiration for the ethical side of Stoicism; he is highly critical of Stoic epistemology. And likewise, Lucullus values both elements in Stoicism, the epistemology and the ethics, but he’s not willing to forego the methods, the practices that have come down from Plato.
This is a key distinction between some of these philosophers and the Epicureans. We probably don’t talk about this enough, but we’re both agreed on this point, Cassius: so much of Epicurean philosophy is presented in such a way that it will be read by these ancient philosophers as a direct response to, and critique of, and rejection of, Platonism. The methods of Platonism, the ethics of Platonism, the skepticism and epistemology of Platonism — every aspect that is enshrined in Plato’s system, in each generation of the Academy as it goes through time, Epicurus is pushing back against all of it. And he’s almost alone in that regard. There aren’t many in the ancient world willing to run the risk, or display the courage required, to go against the grain, especially in Athens, the capital of Greek philosophy at this particular time. Epicurus stands out as someone who, while it’s true that he bases his physics on a particular understanding of Democritus, is rejecting Democritus’ skepticism for the same reason that he rejects it in Plato and in these other schools that have come from Plato.
Now, on the point of whether there can be a true definition applied to a false object, I want to point out a story that will be familiar to almost everyone listening to this, probably. This is one of the most famous episodes in the philosophical theater, if you want to call it that, of fifth- and fourth-century Athens, at the heyday of these philosophical schools. That is the moment when Plato used diaeresis — division, partition. He used logic to cut away and to divide, and to get down to what he considered to be a good definition for a human: a strict classification that would separate humans from other beings, and that would apply only to humans. It’s reported that the definition he came up with is that man is a featherless biped.
Like I said, everybody knows this story. Upon hearing this, Diogenes the Cynic decided to turn the thought experiment into a practical experiment. He plucked the feathers off of a live chicken and carried it into the Academy, held it aloft, and said, “Behold, Plato’s man.”
This is a perfect example of what we’re talking about. Plato thinks he has a true definition — a reliable definition, an epistemically useful definition. But as Lucullus points out, a true definition cannot apply to both a, quote, true object and a false object. And a plucked chicken is not a human. This is a very terse and laconic response by Diogenes the Cynic to Plato’s definition, but it carries within it all of the same criticisms that Lucullus is making about diaeresis, about this over-reliance on logic, on definitions, on divisions, partitions, on syllogisms. And it puts the focus, Cassius, exactly like you were saying, back where it needs to be, on the senses. Everybody in that room could instantly see — they could see with their own eyes — that what Diogenes was holding was not, in fact, a human. It was a plucked chicken. The definition had turned out not to be reliable. The logical procedure that arrived at the definition was immediately suspect.
Plato’s response was to revise the definition to include this new information, and I’m sure people who empathize with Plato and Platonic philosophy would endorse that as the appropriate procedure — that you continue to ignore sensation and just revise and divide and subdivide forever and ever. But I think we can all take a lesson from Diogenes the Cynic there: let’s take this intellectualized, abstract concept in logic and let’s compare it to something real, tangible, physical, that is right in front of us, that we can touch, that we can appraise from multiple distances, from multiple angles. And we can instantly see that the definition, and the logic used to arrive at it, does not hold water.
Lucullus said that in a lot more words than Diogenes is reported to have used, but it’s a similar procedure in responding to Plato. Of course, Lucullus doesn’t go in the direction of saying the senses are the standard. He adds into that this issue of perspicuity, this issue that the only person who can really apply Stoic epistemology is the sage, and the sage is as rare as a phoenix, and all the rest of it. But this is a concrete episode from the halls of the Academy that is worth remembering and worth considering in its full context — the context of diaeresis, and the challenges presented when you accept it uncritically.
And so when Cicero says, in the opening passages of On Ends, Book One of On Ends, that Epicurus is thoroughly destitute in division and partition in logic — maybe that’s not such a bad thing after all.
Cassius:
That’s a great way to conclude it — it’s not such a bad thing after all. It’s actually extremely insightful, for reasons that we’re going to be discussing at much greater length. This section 14 gives us an awful lot to work with, including the specific reference to Epicurus at the end of it. So we’re going to come back next week and continue hammering this point, because Lucullus does have some good argument here combined with some bad argument, and then he sums it all up by referencing Epicurus. We’re going to have the opportunity, as we go through 14, to really bring some clarity to some of these issues.
Let’s stop there for today in the interest of time, but we’ll come back and do that next week. As always, we invite everyone to drop by the EpicureanFriends forum and let us know if you have any comments or questions about our discussions of Epicurus. Thanks for your time today. We’ll be back again soon. See you then. Bye.