Episode 334 - Further Epicurean Analysis of the Problems With Stoic "Kataleptic Impressions"
Welcome to Episode 334 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 start 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 Book Two, where we will take up Section 8
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”Episode 334 steps back from Section 7 of Cicero’s Academic Questions to examine the Stoic concept of katalepsis from two external sources: the Wikipedia entry on katalepsis and Diogenes Laertius’s account of Stoic epistemology in Book 7, Sections 45–46.
The episode identifies three competing positions on sensation: the Skeptics hold that no sensation gives reliable knowledge (all perceptions are acataleptic); the Stoics hold that some impressions are kataleptic — so clearly imprinted on the mind that they constitute genuine comprehension; and Epicurus holds that all sensations are true, while making the crucial distinction that it is only opinions, formed in the mind from evaluating sensations, that can be true or false. Zeno of Citium’s famous hand-gesture illustration — open palm (phantasia), slightly closed (assent), clenched fist (katalepsis), two-fisted squeeze (knowledge) — is read from the Wikipedia entry and examined as an exercise in non-verbal philosophy. Joshua responds with a Zen Buddhism story about a one-eyed monk and a traveler whose silent hand-gesture debate produces two completely different interpretations, illustrating the hazards of bypassing language.
Diogenes Laertius on Stoic epistemology is then read at length: the two species of mental impression (apprehending vs. non-apprehending), the seal-on-wax metaphor, the role of dialectic as an indispensable Stoic virtue, and the Stoic insistence that only through clarity of impression can one withhold or give assent responsibly.
Against this, Cassius reads Lucretius 4.478 (Cyril Bailey translation): no sense can gainsay another, reason cannot override the senses because reason itself is grounded in the senses, and “equal trust must at all times be placed in them — therefore whatever they have perceived on each occasion is true.” This is identified as a direct refutation of the Stoic claim that some impressions are uniquely reliable. No single sensation is ever kataleptic in the Epicurean view; what the mind grasps is the opinion assembled from all sensations considered together over time, which relates to the Epicurean concept of prolepseis.
The episode closes with Lucullus’s passage on things “perceived by the senses after a fashion” — that is white, this is sweet, that is tuneful — and the syllogistic inference “if he is a man, he is a mortal animal partaking of reason.” Joshua notes that the moment you apply a linguistic label like “honey is sweet,” you have already introduced a layer of judgment beyond sensation, a point confirmed by Torquatus in On Ends on pleasure and pain. Cassius previews two topics for the following week: memory as a dimension of Stoic epistemology, and the paradox of motion as a test case for the Epicurean theory of how individual sensations combine in the mind to produce reliable opinions.
Transcript
Section titled “Transcript”Cassius:
Welcome to episode 334 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. We’re continuing in Cicero’s “Academic Questions” from an Epicurean perspective to give us more information and background about the issue of knowledge, how the skeptics were fighting the Stoics and where the Epicurean view fits into this overall question. And we’ve been in Section Seven, which is very deep and we’re probably not going to finish Section Seven today, but before we go further into Seven, I think it would help us to drop back and get a little basic information from two separate authorities on issues that are very relevant to what we’re talking about — possibly the most distinguishing feature of the Stoic approach to knowledge, which is what Lucullus is giving us in the material that we’re reading in Section Seven — is the word “katalepsis” and the concept of a kataleptic impression.
The word “katalepsis” has not come down to us in English in any kind of related word that we use regularly today. Wikipedia tells us that maybe the closest word is “catalepsy,” which is a medical term describing pathological body rigidity, but the Wikipedia entry on katalepsis is brief and I think clear, and if we read that and perhaps a few sections from Diogenes Laertius where he also examined the Stoic theory of knowledge, I think we’ll have an additional perspective that will make what Cicero is telling us here in “Academic Questions” even more clear than it already is. So Joshua, let’s get started today with that approach, and if you would read for us the entry on katalepsis from Wikipedia.
Joshua:
Katalepsis is a term in Stoic philosophy for a concept roughly equivalent to modern comprehension. To the Stoic philosophers, katalepsis was an important premise regarding one’s state of mind as it relates to grasping fundamental philosophical concepts, which was followed by the assent or adherence to the truth thus understood. According to the Stoics, the mind is constantly being bombarded with impressions — or in Greek, phantasia — some of these impressions are true and some are false. Impressions are true when they are truly affirmed, false if they are wrongly affirmed. Cicero relates that Zeno would illustrate katalepsis as follows. He would display his hand in front of you with the fingers stretched out and say, “a visual appearance is like this.” Next, he closed his fingers a little and said, “an act of assent is like this.” Then he pressed his fingers closely together and made a fist and said that that was comprehension.
And from this illustration he gave to that process the actual name of katalepsis, which it had not had before, but then he used to apply his left hand to his right fist and squeeze it tightly and forcibly and then say that such was knowledge — which was within the power of no one save the wise man. That is the end of the quote from Cicero. The article continues: katalepsis was the main point of contention between the Stoics and the two schools of philosophical skepticism during the Hellenistic period — the Pyrrhonists and the Academic Skeptics of Plato’s Academy. These skeptics, who chose the Stoics as their natural philosophical opposites, eschewed much of what the Stoics believed regarding the human mind and one’s method of understanding greater meanings. To the skeptics, all perceptions were acataleptic — i.e., they bore no conformity to the objects perceived, or if they did bear any conformity, it could never be known.
Cassius:
Okay, Joshua, thanks for reading that, and let’s talk about that for just a minute. There’s all sorts of things in what you just read, but I would suggest that possibly the take-home point of all of what you just read was when the article said that the Stoics held that we’re being constantly bombarded with impressions — some of these impressions are true and some are false. I think that stands out immediately to me as the crucial distinction between the Stoics and the Epicureans. And I think we’ve been discussing this to some degree, but it’s only recently sort of crystallizing in my mind that there are three possible positions on whether the sensations are true or not. The skeptics will go in the direction of saying that no sensation is true.
Although we have to think carefully about this, Epicurus is understood to have said that all sensations are true. And in my mind, when I think about these issues, I tend to flip back and forth between “well, none of them are true” or “all of them are true,” but what this is telling us is that the Stoics held a third position — which is that some sensations are true and some are false. And when you focus on that, I think it does help to understand where Epicurus could be coming from in the position that all sensations are true — whatever the sensations are, all of the sensations are of the same rank. And as I think back about what Lucretius says about this in Book Five, I think he says exactly that — that there is nothing more reliable than the senses, that one sense cannot trump another sense, like the sense of smell cannot override the sense of hearing because they have different jurisdictions.
But I think Lucretius also says that even the impression of a sense at different times has to be understood such that one is not more reliable than the other — one doesn’t have any kind of difference in nature from the other. Two observations through the eyes must be given equal weight in your mind in understanding what the truth of a situation is. It’s not like one observation of your eye is true and another one is false — they are always simply observations of the eye, and we have to regard them as that, and not as containing truth or falsity in themselves. But it sounds to me like it’s pretty clear when you read this Wikipedia explanation that Zeno and the Stoics were saying that some sensations are of such a nature that they are in themselves true. And we’ll have to discuss the implications of that as we go forward, but just at a very superficial level: they’re saying some are true and some are false, the skeptics are saying none are true, Epicurus is saying all are true — and we have to unwind it from that point of beginning.
Joshua:
Yeah, I think we can understand some of this through the light of what we’ve already learned through Lucullus in “Academic Questions,” where he says: “the judgments of the senses are so clear and certain that if an option were given to our nature, and if some God were to ask of it whether it is content with its own unimpaired and uncorrupted senses or whether it desires something better, I do not see what more it could ask for.” And then he starts talking about how even though the senses have faults, you can adjust for those faults by changing your facial relationship with the object or casting light upon an object in a different way, and this gives you more confidence. He says we do these many things until our sight causes us to feel confidence in our judgment. Confidence is the thing that we talk about quite a lot when it comes to theories of knowledge in antiquity, and it relates to this Greek word “pistis,” which is the root of epistemology, and it also has connotations of faith which has informed religious traditions from Christianity and elsewhere. But the point of this is that you can do things, manipulate your environment in such a way that you can make your senses work even harder to give you real impressions of the real world — impressions that can be relied upon confidently. I think we would both say, Cassius, that that is good as far as it goes — I mean, Epicurus certainly would say that it doesn’t go far enough.
Cassius:
Yeah, Joshua, exactly. That confidence in knowledge is what we’re after. We haven’t yet decided, as part of this survey of “Academic Questions,” all the details about how you reach that conclusion, but that is a point that unifies the Stoics and the Epicureans against the skeptics — that confidence in knowledge is something you must have if you’re going to live successfully. You cannot start every morning getting out of bed looking around the room as if you’ve never seen anything before, as if you have no idea what’s going to happen, as if every new experience is totally new to you and you cannot have any confidence about whether turning on the light switch is going to start the light or turning on the faucet is going to start the water. You have to act with confidence in order to live your life. So confidence is clearly desirable, and the question is how we attain confidence — as opposed to the skeptics, who say you can’t obtain confidence. If you’re Cicero, maybe you can get a little bit of probability. If you’re Pyrrho, you’re going to reject even that — you’re going to say even probability is a ridiculous standard because nothing is certain in the world of radical skepticism.
Joshua:
Yeah. Let me say one more thing about this passage, and that is this image of the hand grasping. I haven’t really studied enough Stoicism to know what their theory of language is and how that relates to epistemological confidence and so on, but this sort of laconic style of brevity — and let’s try to get things across without solely using words, we’re just going to use images, hand gestures and so on — I’m a bit skeptical of this. And Epicurus thinks that he doesn’t need this because from his point of view, as he says I think in the Letter to Herodotus, that we must grasp the ideas attached to words in order that we may be able to refer to them, and to judge the inferences of opinion or problems of investigation or reflection, so that we may not leave everything uncertain and go on either explaining to infinity or using words devoid of meaning.
And he says for this purpose it is essential that the first mental image associated with each word should be regarded and that there should be no need of explanation if we are really to have a standard to which to refer a problem of investigation or reflection or a mental inference. And I do notice that the English translator in what I quote does use the word “grasp” — that we must grasp the ideas attached to words — which, I don’t know what the Greek is in that passage. This may be one of the ones where he does use words similar to “katalepsis,” but the idea of conveying philosophy using hand gestures reminds me of a story that is popular in collections of stories associated with Zen Buddhism. Because in this story there is a one-eyed monk and he has an elder brother, and they live in a residence with some other monks, and a traveler comes along and applies for lodging.
And the going rule in this culture apparently was that if you could win a debate on Buddhism, then the loser of the debate would have to put you up for the night. So the elder brother, who was deeply and widely read and very erudite in the study of Buddhist philosophy but was very tired, invites him in and then says to his younger brother, the one-eyed monk, “I’m going to go to bed, so why don’t you take this one — but request the debate in silence.” And so they go into a separate room, the traveler and the one-eyed monk, and they engage in this debate and they emerge moments later before the elder brother has even collected his things and retired, and the elder brother asks the traveler what happened. And he said, “I have to move on, because your younger brother beat me in the debate.” And the elder brother says, “relate the dialogue to me.”
And the traveler says, “first I held up one finger to represent Buddha. Then your brother held up two fingers to represent Buddha and his teaching. So I held up three fingers to represent Buddha, his teaching and his followers. Then your clever brother shook his clenched fist in my face to indicate that all three came from one realization” — whereupon the traveler left. And then a moment later the younger brother comes out looking very angry, and the older brother says, “I understand you won the debate.” And the younger brother says, “I won nothing.” He says, “the traveler was a very rude man.” And the older brother says, “well, tell me the subject of it.” And the younger brother says, “the moment he saw me, he held up one finger insulting me by indicating that I have only one eye, but because he was a stranger and I thought it would be polite to do so, I held up two fingers congratulating him on having two eyes. At this, the impolite wretch held up three fingers to show that we had but three eyes between us. So I got mad and threatened to punch his nose and he ran out of the room.” It’s kind of an amusing story that certainly has more layers of meaning in Zen Buddhism, but from the perspective of an outsider it just goes to show the level of misunderstanding that can arise when you rely on hand gestures to try to communicate important philosophical points rather than words, which is something that I would much prefer.
Cassius:
That’s a great story, Joshua, and directly on point — very clear about how difficult it can be to use symbolism to express details of meaning. I’ve never heard that before, so I’m glad you included it. So Joshua, having read from Wikipedia, we always like to go back to the original sources as best we can. And although what I’m about to refer to is not an original source in the sense of being one of the Stoics themselves — just as Diogenes Laertius gave us a lot of detail about Epicurus, he also gave us a lot of detail about the Stoics — I think it would be helpful for us to refer to what Diogenes Laertius summarizes as to the Stoic theory of knowledge. And we have that in Book Seven of his collection of lives of the famous philosophers, starting around Section 45. So 45 I think makes sense to read, 46 makes sense to read as well. Joshua, if you could read for us the explanation that Diogenes Laertius gives us of the Stoic theory of knowledge.
Joshua:
So I’ve quoted the Letter to Herodotus from Epicurus on the subject of language and the meanings of words and definitions, which he generally doesn’t employ as much as we find in other schools — where they’re trying to do things like give definitions of justice that are always true and hold good in every situation and scenario. As DeWitt points out, much in the same way that in geometry you can define regular features like points and lines and triangles and so on, Epicurus mostly dispenses with that. He says we grasp the first mental image that comes to our minds when we’re thinking about words. Diogenes Laertius on Stoic epistemology says this. He says: “Now the part which deals with canons or criteria, the Stoics admit as a means for the discovery of truth, since in the course of it they explain the different kinds of perceptions that we have.
“And similarly, the part about definitions is accepted as a means of recognizing truth, inasmuch as things are apprehended by means of general notions. Further, by rhetoric they understand the science of speaking well on matters set forth by plain narrative, and by dialectic that of correctly discussing subjects by question and answer. Hence their alternative definition of dialectic as the science of statements true, false, and neither true nor false. Rhetoric itself, they say, has three divisions: deliberative, forensic, and panegyric. Rhetoric according to them may be divided into invention of arguments, their expression in words, their arrangement, and their delivery — and a rhetorical speech into introduction, narrative, replies to opponents, and peroration. Dialectic, they hold, falls under two heads. The first head is discourse, and the second head is language. And the subjects of discourse follow under the following headings: presentations and the various products to which they give rise, propositions, enunciated and their constituent subjects and predicates, genera and species, arguments, moods, syllogisms and fallacies — whether due to the subject matter or to the language — these including both false and true, and negative arguments, the so-called syllogism, and so on, whether defective, insoluble, or conclusive, as well as the fallacies known as the veiled or horned, the no-man, and the mowers.
“The second main head mentioned above belonging to dialectic is that of language, wherein are included written language and the parts of speech, with the discussion of errors in syntax and in single words, poetic diction, verbal ambiguities, phonics and music. And according to some writers, chapters on terms, divisions, and style.”
It occurs to me to interject here to say that Cicero at one point criticizes Epicurus for not using categories — he doesn’t categorize things neatly, and this I think would be one example of what he’s talking about when he’s talking about philosophers categorizing things, placing them into nesting buckets where everything is nice and neat and orderly, but doesn’t make any sense to the casual observer, which in some sense we are at this moment.
“In 45 he continues: ‘The study of syllogisms, they declare, is of the greatest service as showing us what is capable of yielding demonstration, and this contributes much to the formation of correct judgments and their arrangement and retention in memory gives a scientific character to our conception of things. An argument is in itself a whole containing premises and conclusions, and an inference or syllogism is an inferential argument composed of these. Demonstration is an argument inferring by means of what is better apprehended something less clearly apprehended.’”
We’re using in demonstration an argument — we’re using something that is grasped to infer a conclusion about something that is not grasped, I think is what he’s saying there.
“‘A presentation or mental impression is an imprint on the soul, the name having been appropriately borrowed from the imprint made by the seal upon the wax. There are two species of presentation: the one apprehending a real object and the other not apprehending a real object. The former — which they take to be the test of reality — is defined as that which proceeds from a real object, agrees with that object itself, and has been imprinted seal-fashion and stamped upon the mind. The latter, or non-apprehending — that which does not proceed from any real object, or if it does, fails to agree with the reality itself, not being clear or distinct.
“‘Dialectic, they said, is indispensable and is itself a virtue embracing other particular virtues under it. Freedom from precipitation — which is a kind of hastiness or rashness in action — is a knowledge of when to give or withhold the mind’s assent to impressions. And by wariness they mean a strong presumption against what at the moment seems probable, so as not to be taken in by it. Irrefutability is strength in argument so as not to be brought over by it to the opposite side. Earnestness or absence of frivolity is a habit of referring presentations to right reason. Knowledge itself they define either as unerring apprehension or as a habit or state which in the reception of presentations cannot be shaken by argument. Without the study of dialectic, they say, the wise man cannot guard himself in argument so as never to fail, for it enables him to distinguish between truth and falsehood and to discriminate what is merely plausible and what is ambiguously expressed. And without it he cannot methodically put questions and give answers. Over-hastiness in assertion affects the actual course of events so that unless we have our perceptions well-trained, we are liable to fall into unseemly conduct and heedlessness, and in no other way will the wise man prove himself acute, nimble-witted and generally skillful in argument. It belongs to the same person to converse well and to argue well, to put questions to the purpose and to respond to the questions put.’”
And all these qualifications are qualifications belonging to the skilled dialectician. Such, summarily stated, is the substance of the logical teaching of the Stoics.
Cassius:
Joshua, I have a feeling that rather than me jump in with some commentary right now, since you’ve just read through this, I bet there are some things in your mind that you’d like to go ahead and focus on. So what do you think about what you just read?
Joshua:
Well, the key thing for our purposes is this metaphor of an impression which is like a seal upon the wax. This impression strikes your soul or strikes your mind, and he says there are two species of presentation or mental impression: the one apprehending a real object and the other not. The former — which they take to be the test of reality — is defined as that which proceeds from a real object, agrees with that object itself, and has been imprinted seal-fashion and stamped upon the mind. The latter, or non-apprehending: that which does not proceed from any real object, or if it does, it fails to agree with reality itself, not being clear or distinct. This seems to me to give us the argument that we’ve been tracking in “Academic Questions” on the partial reliability of sense perception in gaining access to the truth.
Lucullus has said, while speaking on the topic of sense perception and its accuracy: “you do not need to wait while I reply to the illustration drawn from a bent oar in the water, which we know to be straight, or the neck of a dove” — in the same context where “I am not a man to say that everything which seems is exactly of that character of which it seems to be; Epicurus may deal with this idea and with many others, but in my opinion there is the very greatest truth in the senses” — and then we get the caveats: “if they are in sound and healthy order and if everything is removed which could impede or hinder them.” And this is why we might wish under certain situations for the light to be changed, or for the situation of the object to be changed, or for it to be closer or further from us, or for it to be rotated so we get a different look at it, and so on.
And this is what allows us to be confident. But he’s already said here that he’s not dealing with every sense perception, because not every sense perception can be grasped. I think that’s the basic idea we get in Diogenes Laertius. He gives a slightly different turn on that, though, which I think is saying the same thing but says it in a slightly different way. In Diogenes Laertius he says there are two species of impression: the one apprehending a real object and the other not apprehending a real object — but nevertheless the impression is still there. It’s not just that we get impressions from some things in nature but not from others — we get impressions from everything in nature, but only some of those impressions are reliable. So only some of those impressions give us confidence. And like I said, it’s the same argument stated slightly differently. And Lucullus does say that he’s not going to account for the straight oar that looks bent when it’s in the water, because he’s already accepted this.
He’s already accepted the Stoic view that some mental impressions correspond to real objects and some do not. And the impression of a bent oar is an impression that does not correspond to something real in nature. The oar might be real, but we don’t have to fall all over ourselves from the Stoic point of view to defend sense perception when it is clearly showing us something that does not accord with the known facts — the fact of the oar being straight. Now Epicurus answers that objection in his own way, and he does it while maintaining the reliability of the senses. But here we have, as you said, Cassius, a kind of middle ground between the hard-line skeptic — which says that nothing can be grasped that comes to us through the senses — and Epicurus, who says in a way that requires some explanation that all sensations are—
Cassius:
Joshua, let’s draw that out because I think people hearing you think your way through it is going to be helpful. How do we judge what you’ve just been talking about from Lucullus and the Stoics? How do we evaluate that from an Epicurean perspective? Yes, it’s one thing to say that the Epicureans say that all sensations are true and the Stoics say that some are true and some are false, but let’s go one step further. Why would Epicurus dispute what the Stoics have said? How would Epicurus substitute something else for saying that some are true and some are false? When does Epicurus say that we can be confident that an opinion that we have reached through sensation is true? Do you simply get close to the tower and then a sensation at that moment becomes a true one? Do you move to another angle and that sensation from that angle you grasp so tightly with your fist that you’re sure that it’s true? I don’t think that’s what Epicurus would say, but you work through it for us. How are you thinking about that? How would you explain, in that context, that all sensations are true and therefore what we need to do with those sensations?
Joshua:
We’ve been having discussions on the forum recently about why do you look to the analogon in your determination that pleasure is matter for approval and pain for aversion. And this isn’t exactly related to that, but the direction that Thomas Jefferson goes in explaining this I think is very useful, and it’s similar in the sense that you don’t have to have language in order to think along these lines, perhaps. I mean, it’s very difficult to imagine what thinking looks like without language, but he kind of imagines himself in a situation where he’s in an environment and things are in his immediate vicinity, and what can he do in order to learn about this situation? And what he says is: “I feel, therefore I exist. I feel bodies that are not my own — there are other existences. I feel them changing place — this gives me motion. Where there are no bodies, I call it void or immaterial space.”
And he says from these few sense perceptions he is able to build up all the certainties that he will ever need or have. And the claim that these sense perceptions are true is a difficult one, because in Epicurean philosophy the judging faculty is really in the mind. What the senses are — an analogy that we’ve used before — is that the senses are just witnesses in court. These are witnesses to our environment that are just giving us information, and they’re giving us this information without any added opinion. There’s no layer of opinion added by sensation, and there’s no judgment going on in these faculties that colors that information as it is coming into us. The senses are not omniscient, they don’t see everything, but they don’t mislead about what they do see — they’re just reporting the facts, they’re just reporting the evidence that is available to them. It’s streaming into every one of our senses all the time.
Cassius:
Joshua, do you agree that Lucullus is saying that some of those impressions that we receive come from real things and that they are so impressed upon us as a seal upon wax that we can judge that those sensations are true?
Joshua:
Well, not exactly, no, because what Diogenes Laertius is saying that the Stoics are saying is that both the grasped and the non-grasped mental impressions impress upon us like a seal upon wax.
Cassius:
Okay, so that would be a description of sensation — that the things that we are receiving are all impressions. Do you agree that they are seeing some impressions as more reliable than others?
Joshua:
Yes.
Cassius:
And how are they judging which of those sensations are more reliable?
Joshua:
I mean, what he says is that with some sensations there is a kind of clarity that inspires certainty, and that in other sensations there is less clarity, less distinction — it’s fuzzy around the edges, as you could almost say — and that it’s only when this clarity is present that you judge one sense perception to be true and another one to be false.
Cassius:
I think that’s very well stated. Clarity, I think, is a good word to be using. It’s not exactly the same as “kataleptic,” but I think that’s what they’re talking about — that they think certain types of impressions are so clear that we have some ability, potentially or largely through dialectic as they keep talking about dialectic, to determine that some impressions are so clear that they alone are to be trusted and that the others should be disregarded for the time being at least. Maybe that’s a working way of discussing it. I would like to refer us in this context over to Lucretius, who probably gives us the most detail that’s been preserved from the Epicurean texts about Epicurus’s views on these things. Book Four, around line 478. And let me read a little bit of this — and I’m going to single out a particular sentence. I mentioned this earlier and I want to tie it down by going to Lucretius himself, 4.478 — and I’m reading the Cyril Bailey version.
“You’ll find that the concept of the true is begotten first from the senses, and that the senses cannot be gainsaid, for something must be found with a greater surety which can of its own authority refute the false by the true. Next, then, what must be held to be of greater surety than sense? Will reason, sprung from false sensation, avail to speak against the senses, when it is wholly sprung from the senses? For unless the senses are true, all reason too becomes false. Will the ears be able to pass judgment on the eyes, or touch on the ears? Or again, will the taste in the mouth refute the touch? Will the nostrils disprove it, or the eyes show it to be false? It is not so, for each sense has its faculty set apart, each its own power. And so it must needs be that we perceive in one way what is soft or hot or cold, and in another the diverse colors of things and see all that goes along with color. Likewise, the taste of the mouth has its power apart and one way smells arise, and another sounds. And so it must needs be that one sense cannot prove another false.”
Now so far I think we’re all very familiar with what he’s been saying — one sense cannot judge another sense, reason cannot override the senses because reason is based on the senses and reason is not some kind of outside force that is more reliable than the senses. So in that aspect I think we’ve got a direct refutation of this issue — that dialectic or some kind of faculty of reason as alleged by the Stoics is going to tell us which senses are correct and which ones are not. They have to work together and not at odds with each other. And that’s the way I’ve generally been looking at this. Most of my time spent reading Epicurus is that that is the most important part, but now that I see where the Stoics are coming from — in terms of saying that some impressions constitute kataleptic impressions that can be taken on their own as true, that this sensation is true and another sensation is false — I would go to the next line and I think this hammers home the refutation of that point, because the next sentence in 4.478 here says: “And so it must needs be that one sense cannot prove another false. Nor again will they be able to pass judgment on themselves, since equal trust must at all times be placed in them. Therefore, whatever they have perceived on each occasion is true.”
And so to me, I look at that now and see this is a direct argument against some impressions being true, some kataleptic impressions being reliable and others being false. Epicurus is saying — Lucretius is saying — that we always have to give credit to what the senses are reporting, and at no time, no matter how clear, no matter how close we are to some particular object, that sensation at that moment is not the gold standard of truth for all time. The direction that I would say he seems to be going here is: we always have to accept the sensations as being reliable, and it’s only continuously comparing the sensations over time that we can begin to form an opinion as to the reliability of truth coming from the repeated sense. No one sensation deserves the label of being a kataleptic impression.
All sensations are in the same condition, and at the same time are something that has to be given credence to. So when I relate this to the idea of prolepseis and repeated exposure to certain things leading you to conclusions, there’s all sorts of complexity involved in unwinding all that, but it seems to me that Epicurus is going to tell us that no single sensation is ever sufficient to in itself deliver us a true opinion — that the mind has to take all of the evidence in hand, weigh it, balance it, sift it, and conclude that in the end it is more likely than not, there is no reasonable probability of any other possibility being true other than what the weight of the senses provide to us. So I don’t know that I’m going to be able to stick with that way of articulating it for very long, but at least at the moment, as I’m thinking about what we’re reading here, I’m going in that direction as to how to weigh all this. No single sensation is ever kataleptic from the Epicurean viewpoint — and in fact, you would never say, even if we use the English term “grasp,” you would not look at it in terms of “I grasp the sensation.” What you grasp is an opinion that you form after the evaluation of all of these sensations in the mind.
Joshua:
My main thing to say is to ask you what you mean exactly by “no single sensation” — or “no single perception,” I can’t remember how you worded it.
Cassius:
Yeah. I think, as I’m evaluating it now, when I look at my computer right this second at 11:04 AM on May the 17th of 2026, I’m going to look at the computer again a moment from now, and that is going to be a different sensation. And I have to accept all sensations sequentially as they come — almost thinking about how Velleius describes the gods being received by us as images floating through the air. It’s almost like we are constantly having to assemble from individual discrete images or smells or sounds — we are constantly required to assemble those discrete data points into this pattern, which I think we talk about in terms of prolepseis as well. So that’s where I’m going with that.
Joshua:
I think that’s the right way to put it. The reason I mention that is because sometimes when I read that passage in Lucretius, the idea is that one sense faculty cannot gainsay another — your sight of the thing cannot gainsay what touching the thing has already told you, and likewise your experience of touching it cannot overwrite what you have perceived through seeing it. But to push it deeper and realize it’s not quite as rigid as that — that it’s any impression that strikes upon you that cannot be gainsaid by any other impression, whether from the same sense faculty or from a different one — I think that’s probably worthwhile to explain a little bit. I know that when I’ve read Lucretius, that has sometimes not emerged as an obvious conclusion.
Cassius:
That’s exactly why I’m stressing it now, because it has not been obvious to me either that this was so important. But when I compare it and realize that the Stoics were asserting that certain types of impressions are undeniably true, I begin to realize that that’s not what Epicurus is saying about any sense — that any time they provide the perceptions that allow us to judge truth in our minds, that allow us to form true and false opinions — how many times have we said that we don’t think the senses are true? It is opinions that are true. And I think that’s pretty clear from Epicurus’s discussion. That’s why Lucullus is saying, “I don’t care to debate with Epicurus as to whether all sensations are true — I’m just going to defend that some are true.” Well, that’s the reason why this is also important — because a sensation is not truth in that sense.
It’s not a comprehension, it’s not an understanding, it’s not an opinion, it’s not a concept. Senses are pre-concepts. That’s the word that drives me crazy when I see Cyril Bailey sometimes use the word “concept” for “prolepseis” instead of “pre-concept.” Senses, prolepseis, even feelings of pleasure and pain — I don’t think Epicurus would say those are opinions. Opinions are concepts formed after thinking about things and deliberating in the mind. But I don’t need my mind for my finger to tell me that if I put a hand on the stove it’s going to be hot. I don’t need the mind to evaluate and put a label — and translate into English, French, and Latin — what it means to be hot. I can immediately feel these things, and those sensations are not the same thing as understanding or knowledge or comprehension. But the Stoics appear to be taking the opposing position.
Joshua:
And that’s a perfect analogy, because that instantaneous pulling-your-hand-away-from-a-hot-stove is a true reflex — meaning that the brain is not involved in that nerve impulse. The information goes from the senses in your hand to your spinal cord, and the spinal cord itself immediately fires back the response “pull the hand away” — it doesn’t even go as far as what we consider to be the seat of reason in the brain, which supports the mind. But there is another passage in what Lucullus says which I did want to get your thought on after having read what you’ve just read and after this discussion, because he says: “But such as those things are which we say are perceived by the senses, such also are those things which are said to be perceived not by the senses themselves, but by the senses after a fashion — for example, that is white, this is sweet, that is tuneful, this is fragrant, that is rough.”
“We have these ideas already comprehended by the mind, not by the senses. Again, this is a house, that is a dock. Then the rest of the series follows connecting the more important links: such as these, which embrace as it were the full comprehension of things: ‘if he is a man, he is mortal; if he is a man, he is a mortal animal partaking of reason.’ From which class of arguments the notions of things are impressed upon us, without which nothing can be understood nor inquired into nor discussed. But if those notions were false” — for you seem to me to translate the Greek word as “notions” — “if I say they were false, or impressions or perceptions of such a kind as not to be able to be distinguished from the false ones, then I should like to know how we were to use them and how we were to see what was consistent with each thing and what was inconsistent with it.”
That’s the end of that paragraph. But the key point that I wanted to make is he seems to recognize that the moment you employ language, you’re kind of making a judgment already. When you describe something as “white,” that is not a sensation — that’s a description, and the description requires that some kind of thought process be put into it, however minor. And we can compare this with what Torquatus says in “On Ends,” where again on the subject of pleasure and pain, he says: “we don’t need to support the idea that pleasure is the good by elaborate argument any more than we need to support by elaborate argument the idea that honey is sweet and snow is white and fire is hot” — exactly the same point you made, Cassius, about the hot stove. I’m quoting that from memory, so I don’t remember exactly what the context is there. But to clarify, Lucullus is saying those are not sensations. It’s not a sensation that honey is sweet — “honey is sweet” is a linguistic description, a label that we’ve applied to that sensation. And then, because he’s interested in reason and dialectic and so on — and that kind of forms the core of so much of the Academic Skeptic canon of epistemology, but also of the Stoic system — the moment you’ve introduced language and comparison, then we can start getting into syllogisms. Then we can get into what he says is “the full comprehension of things” — the class of arguments from which the notions of things are impressed upon us, without which nothing can be understood nor inquired into nor discussed. But if those notions were false, then he should like to know how we were to use them. We can probably continue this conversation next week and may have to, but this does follow along with what we were just talking about, Cassius.
Cassius:
It certainly does, Joshua, and we are going to run out of time for this week, but you’ve clearly hit on a very important aspect of all this that we have talked about in the past, but we’re going to have to continue to talk about. And the way I would describe what the issue is here is that there clearly is a process in life that we often call conceptual reasoning. When we say “honey is sweet, snow is white” — that is a language-labeling system in which we have concepts of honey, concepts of “is,” concepts of “sweet.” We have to process these words and in words we use definitions. And it is clear that everybody agrees that that is a process that has to be understood. I don’t think there’s any sense in which Epicurus rejects conceptual reasoning as not being useful. The issue is not whether conceptual reasoning is useful — because “A plus B equals C,” any kind of abstract formulas, those can be highly useful and everybody understands that. What becomes the issue is not conceptual reasoning alone, but the issue of how you get to the process of conceptual reasoning in the first place.
How do you ever validate anything as true or false, to begin to manipulate it through conceptual reasoning? And we know that Plato was suggesting that the way we know things is that we were existing in another dimension before we were born and knowledge is the process of remembering things from our past lives — well, that’s not going to fly with Epicurus. Therefore we come up with a system which I think is described under the general category of prolepseis, in which our minds are endowed with the faculty of organizing things automatically — which are what is referred to as prolepseis or preconceptions — which gives us something to work with when we start talking about conceptual reasoning. So I think we’re going to have to keep both categories in mind, and it is important to keep them separate — I think they are two separate things. Gosh, we are going to run out of time for today. And let me close by saying that one thing I want to address next week also is going to be this: when we address, as we have many times in the past, the issue of the paradox of motion — the idea that it is impossible to walk across a room, that motion is impossible is the general category of the assertion.
I think in the past I have tended to say that the way you prove that motion is possible is to simply point to somebody who is walking across the room. Given our recent discussions here today, even about all sensations being true, I don’t think that’s a sufficient way of looking at it — because I think what you have to do is go further. From any single sensation, even those sensations in which you are observing something at different locations, you’ve got to have a theory of understanding in which you articulate how these observations add up to an opinion that is true, always keeping in mind that opinions can be true or false, but the sensations are never true or false in that sense — the sensations are just perceptual data, all of which you have to treat as true, including the moment that you look at something and it stays in a single position. That observation is just as reliable as the observation in which an object appears to be changing positions. You have to have an articulate method of explaining how the mind takes these individual sensations and converts them into opinions that we think are true or false. And Epicurus has a theory of that which is very distinct from the idea that certain impressions are themselves true. But let me let you have the last word, Joshua, and then I’ll close this out.
Joshua:
I think it’s been very helpful, Cassius, to go through in this level of detail and to consult these other sources as well, because we are going to be going even deeper into some of this. I think perhaps next week we’re going to get into the question of memory: “What memory,” he says, “can there be of what is false? Or what does anyone remember which he does not comprehend and hold in his mind?” So there’s going to be many, many more deep conversations to come on these questions. I think we would both say that the study of Stoic epistemology is something we have put off for far too long, because confronting it has been very interesting.
Cassius:
I agree, Joshua, and we will continue to do that next week. In the meantime, we invite everyone to drop by the Epicurean Friends Forum and let us know if you have any questions or comments about this or any of our other discussions of Epicurus. Thanks for your time today. We’ll be back again soon. See you then. Bye.