Episode 108 - The Benefits of A Proper Understanding of the Senses and of Natural Science

Date: 02/10/22
Link: https://www.epicureanfriends.com/thread/2386-episode-one-hundred-eight-the-benefits-of-a-proper-understanding-of-the-senses-a/

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Summary

Continuing in section 64 of the Torquatus text, this episode focuses on the Epicurean defense of the reliability of the senses against radical skepticism. Cassius opens with a passage from Diogenes of Oenoanda attacking those who claim things are unknowable and thereby destroy the grounds for natural science, then quotes his argument that the Aristotelian flux theory undermines itself. Joshua introduces Pyrrho of Elis and the Aristocles passage summarizing Pyrrhonism’s radical conclusion that we should be “without views, uninclined toward this side or that, unwavering in our refusal to choose” — which Cassius identifies as the inevitable endpoint when you deny the reliability of the senses. Extended readings from Lucretius Book 4 follow, covering the defense of the senses against the skeptics’ use of optical illusions and culminating in the building-on-crooked-foundations metaphor. Principal Doctrines 23 and 24 are discussed, Joshua’s flat-earth example illustrates how senses and natural understanding correct each other, and Joshua closes with Thoreau’s story of the traveler who discovers the swamp has a hard bottom after all.

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Transcript

Cassius:

Welcome to episode 108 of Lucretius Today. This is a podcast dedicated to the poet Lucretius, who wrote On the Nature of Things, the only complete presentation of Epicurean philosophy left to us from the ancient world. I’m your host Cassius, and together with our panelists from the EpicureanFriends.com forum, we’ll walk you through the six books of Lucretius’s poem and we’ll discuss how Epicurean philosophy can apply to you today. We encourage you to study Epicurus for yourself, and we suggest the best place to start is the book Epicurus and His Philosophy by Canadian professor Norman DeWitt. If you find the Epicurean worldview attractive, we invite you to join us in the study of Epicurus at EpicureanFriends.com, where you’ll find a discussion thread for each of our podcast episodes and many other topics.

At this point in our podcast, we’ve completed our first review of the poem, and we’ve turned to the presentation of Epicurean ethics found in Cicero’s On Ends. Today, we return to section 64 of book one, and we discuss the Epicurean reliance on the senses and the benefits of natural science. Now let’s join Joshua reading today’s text.

Joshua:

“…and say the perception is altogether impossible, cannot even clear the way for this very argument of theirs when they have thrust the senses aside. Moreover, when cognition and knowledge have been invalidated, every principle concerning the conduct of life and the performance of its business becomes invalidated.

So, from natural science, we borrow courage to withstand the fear of death and firmness to face superstitious dread and tranquility of mind through the removal of ignorance concerning the mysteries of the world, and self-control arising from the elucidation of the nature of the passions and their different classes. And as I showed just now, our leader again has established the canon and criterion of knowledge and thus has imparted to us a method for marking off falsehood from truth.”

Cassius:

Joshua, thank you for reading that today. We are continuing in the discussion of Torquatus about the issue of the benefits of natural science. Last week we introduced the topic and this week we’re going to go further on the same topic with several different tangents we could take and different paths we could pursue if we choose to, especially about this issue of mental perceptions that is listed in the second of the sentences that you read there.

But there’s a lot of just general basic material here too that we can start off with. And probably the best thing to do — we did some of this last week with this very same sentence — but probably the best thing we could do is to emphasize the implications of the very first sentence that says, “Moreover, unless the constitution of the world is thoroughly understood, we shall by no means be able to justify the verdicts of our senses.”

The significance of that first sentence being that we certainly want to be able to take the position that — when it says “the verdicts of our senses,” in other words what we observe around us — we want to be able to take a position as to whether our opinions about those things are correct or incorrect. I think that’s what he means in terms of the verdicts of our senses. Any observation that our eyes or ears or nose makes, we want to be able to justify that the conclusions we reach about those perceptions are repeatable and are firm and are not just the result of a hallucination or some crazy episode in our mind.

Maybe one of the best examples of a statement about that is contained in Diogenes of Oenoanda — in that inscription in Turkey, which we’ve talked about before. There is a statement that Diogenes makes that the commentators like to talk about because they think that he’s referring to the wrong philosopher. But Fragment Five states this — this is the Martin Ferguson Smith translation: “Others do not explicitly stigmatize natural science as unnecessary, being ashamed to acknowledge this, but use another means of discarding it. For when they assert that things are inapprehensible, what else are they saying than that there is no need for us to pursue natural science? After all, who will choose to seek what he can never find?”

In other words there, before I go on to the second paragraph — if you start out with the presumption that your senses cannot be validated, that your conclusions can’t be justified, then why don’t you just give up and go home and sit in that cave that people talk about sometimes, because you’ve crippled yourself at the very beginning by saying that your perceptions and your senses are incapable of reaching any conclusions.

And that, of course, is not Epicurus’s position. And here’s the real point that I wanted to read, and this is a quote: “Now Aristotle and those who hold the same peripatetic views as Aristotle say that nothing is scientifically knowable because things are continually in flux and, on account of the rapidity of the flux, evade our apprehension. We” — meaning the Epicureans — “we, on the other hand, acknowledge their flux, but not its being so rapid that the nature of each thing is at no time apprehensible by sense perception.”

So in other words there, he’s saying that Epicurus held that, yes, a flux exists in the sense of the atoms being constantly in motion within the void, but that the constant motion of the atoms in the void is not so rapid that we can’t make sense out of it through our senses. That’s the ultimate position there. And continuing on, quote: “And indeed, in no way would the upholders of this view under discussion have been able to say — and this is just what they do maintain — that at one time this is white and this is black, while at another time neither this is white nor that black, if they had not had previous knowledge of the nature of both white and black.”

Okay, that’s the end of that quote, and there’s more on the same topic in Lucretius, which we can talk about in just a few minutes as well.

But maybe that sets the stage for the basic point here — that Epicurus is saying that unless the constitution of the world is thoroughly understood, in other words unless we have a position about the nature of the world in Epicurean terms operating through atoms and void, unless we understand that and we understand that the atoms don’t move so quickly that we can’t have any perception of them, then we have no way to justify the verdicts of our senses.

So I don’t think it’s possible to overemphasize this point that Epicurus is saying: unless you have an understanding of physics that allows you to take a firm position on the opinions that you reach from your perceptions, then everything is just in flux, totally arbitrary, totally uncertain, and could change at any moment, and your life would be basically impossible to live because you’d have nothing firm on which to stand at all. And okay, that’s enough of my rant. Joshua?

Joshua:

Yes, yes. So you’ve kind of gone the direction of bringing in Diogenes of Oenoanda and Aristotle and his position into this. There was another position that was sort of equally problematic, and that is you had this guy named Pyrrho — who was Greek. He had actually studied in the Greek tradition. And then when Alexander the Great went on his long march east, Pyrrho went with him, and they made it as far as India, or at least the other side of Bactria, which is near enough to the Indian culture. And Pyrrho had made a point to go listen to the philosophers in India — the Magi or whatever they might have called themselves at the time. And when he came back, he came back having heard things from the great thinkers of India that were completely different from anything that anyone in Greece had come up with.

And so you’ve got this great civilization on the other side of this continent, and they’ve come up with completely different conclusions to the conclusions that were come up with in Greece. And so Pyrrho — what he got out of that, what he took away from that knowledge — was: we can’t be sure of anything that we think is true, because everybody else in the world is looking at the same sort of problem. They’re living in the same universe, and they all come up with different explanations for themselves.

And so that’s, I think, part of what we’re getting at here with “unless the constitution of the world is thoroughly understood, we shall by no means be able to justify the verdicts of our senses.” There are two things going on here. One of them is that our understanding of the constitution of the world — it’s kind of a check against our senses. And our senses are kind of a check against the constitution of the world and how it appears. And so with the two of these together, you get at the heart of what is really going on in nature, because sometimes things happen in nature that appear to be operating in one way and yet are actually operating in a different way.

But the senses — which in the modern age we augment with instruments — can sort through these problems. One example that perplexed ancient thinkers but has been solved more recently is the problem presented by the stars in the sky, because some people thought that the stars were fixed on the inside of a sphere that was moving. Some people thought that the stars each had their own motion, but the problem was the stars were so far away that we couldn’t detect motion between stars — they all seemed to be stationary in their one point in the sky. This is known as stellar parallax. And it wasn’t until we developed instruments like telescopes that were capable of detecting this parallax that we were able to finally put this problem to bed. So this is a situation in which our understanding of nature can give information to our senses, and our senses can sort of sift information about what’s going on in nature.

Cassius:

That was good, too. I agree with what you just said, Joshua. Martin, what would you add to what we’ve said so far?

Martin:

Oh, I have nothing to add at the moment.

Cassius:

Okay, all right. Well, I suspect you’ll have some things to say before we get through today, because this is pretty close to your area of expertise as well.

Martin:

Yeah, so to comment on what Joshua just said — yes, Epicurus was battling skepticism. I think that is a key aspect of Epicurean philosophy. DeWitt talks about it a lot. DeWitt talks about how Epicurus apparently considered even Plato a skeptic and that he needed an alternative means of establishing how to prove what’s right and wrong, rather than Plato’s ideal forms, which Plato suggested was not comprehensible by the senses.

You know, this whole issue of empiricism and so forth that occurs is a huge underlying battle in ancient philosophy as to how much confidence to put in the senses and what are the limits of the senses, and whether reason and certain types of logic, certain assertions through logic, can be used to overcome the senses and under what circumstances they should be used.

Cassius:

I should emphasize — and Joshua reminded me of the Diogenes of Oenoanda quote — the commentators find it interesting that Diogenes was criticizing Aristotle in particular, because they think that possibly Aristotle’s position on the flux is not consistent with what Diogenes of Oenoanda is saying here. And I have no clue which is correct and whether Diogenes of Oenoanda got it wrong, despite all of his access to the ancient philosophers and texts since he lived back in that period, or whether we have it right today, or who’s right or who’s wrong about Aristotle in particular.

But clearly there was a significant segment of ancient philosophy that thought that there was a flux moving so fast that it’s just impossible through the senses to get a grasp with confidence of anything at all. And of course, “anything at all” is a key phrase there, because these people were saying that you can’t have confidence in anything that you perceive through the senses — that there’s no way to validate and take a position that you’re right and someone else is wrong about your conclusions through the senses, because everybody’s senses are different and they’re just not reliable and they’re subject to all sorts of illusions and deceptions and errors.

Oh my gosh, we could spend weeks on this passage right here and we’re not going to be able to do that. But before we just go into these additional details, that reminds me — someone wanting to read further into this needs to take out Lucretius Book 4. And this is also related to the issue of “all sensations are true.” I don’t know if we’ve discussed that recently here on the podcast or not, but the allegation that Epicurus took the position that all sensations are true and therefore reliable — what that means and what he meant when he said something to that effect.

Probably the best explanation of all of that is in Lucretius Book 4. And to relate it and try to keep focused on what we’re talking about today — where we’ve just read the sentence that says we shall not be able to justify the verdicts of our senses unless we understand the constitution of the world — the opening sections and probably at least the first half of Book 4 is devoted to discussions of illusions. And Lucretius gives example after example — and these would have come directly from Epicurus’s own book — that there are all sorts of illusions out there that we are familiar with. That when you’re on a ship and you’re looking at the seashore and you’re moving, it looks like maybe the seashore is moving instead of you. When you put an oar in water, it looks like it’s bent. All sorts of illusions can occur.

And so the skeptics use those illusions to ask the question: “Well, obviously the senses can be deceived, so therefore you can’t rely on the senses.” And Epicurus had to come up with a response to that if he’s going to avoid the total skepticism that you can get into if you follow that to its logical conclusion. You can just be a pure skeptic and say that nothing is certain whatsoever and the best you can do is probability. But you should always take the position that, “Well, maybe you’re wrong and maybe the sun is not hot and maybe the water is not wet because tomorrow it might not be wet.” Any number of observations of illusions can be brought out.

And so the next sentence here is that further our mental perceptions all arise from our sensations. And if these are all to be true, as the system of Epicurus proves to us, then only will cognition and perception become possible. Let’s talk about that for a few minutes. And we should comment that there are many differences of opinion about some of the details of what Epicurus was saying, especially in this sentence.

The phrase “mental perceptions” — it’s probably pretty safe just to stay on kind of a superficial level and say that the things we think about, the opinions that we form, arise from the perceptions that we receive from our eyes and ears and touching things and so forth. And you can just stay on that level and fully take the important point that if our opinions about what we see and hear and touch are to be true, only then does cognition and perception become possible. Joshua, what do you make of that sentence?

Joshua:

OK, so what we’re talking about here really is the canon of knowledge, or the criterion of how we know what we know. And for the classical Epicureans — I should say maybe the Greek Epicureans, as opposed to the later Hellenistic Epicureans — that canon had three legs. You’ve got sensation, prolepsis, and feelings.

And the commentary on this problem has kind of made things rather confusing, as you said, because the word prolepsis can be translated in any number of different ways. It can be translated as concepts, as conceptions, as anticipations. And so it’s quite difficult to get a handle on this particular aspect of this material. But the key takeaway is what we were just saying a moment ago.

And I’m going to read something from this rather complicated passage from Pyrrho. Actually, he didn’t write it. According to Wikipedia, this is a summary of Pyrrho’s philosophy, preserved by Eusebius quoting Aristocles quoting Timon, in what is known as the Aristocles passage. But it’s describing Pyrrho’s thoughts. And even here it says there are conflicting interpretations of the ideas presented in this passage, each of which leads to a different conclusion as to what Pyrrho meant.

And he says, whoever wants to live well must consider these three questions: First, how are ethical matters? How are they by nature? Second, what attitude should we adopt toward them? Third, what would be the outcome for those who have this attitude?

Pyrrho’s answer is that these matters are undifferentiated by a logical differentia. So that’s already getting quite complicated. They are unstable, unbalanced, and unmeasurable, and they are unjudged, unfixed, and undecidable. Therefore neither our sense perceptions nor our doxai — which you may remember from Epicurus, the Principal Doctrines, the kuriai doxai, or views, theories, or beliefs — neither our sense perceptions nor our views tell us the truth or lie. So this is getting really complicated. We can’t even know whether they are telling the truth or lying or not. So we certainly should not rely on them.

Rather, we should be — and this is really where it gets to be a problem — we should be without views, uninclined toward this side or that, and unwavering in our refusal to choose a position. Saying about every single one that it no more is than it is not, or it both is and is not, or it neither is nor is not. Very quickly sinking in quicksand here.

So that’s the nature of the problem, or I guess one aspect of the nature of the problem, because we’ve so far talked about Aristotle and his position. You mentioned Plato, Cassius, and his position — best described I think by his allegory of the cave, where you think you’re in the world of the living and the world of a true understanding of nature, but in fact you’re sitting in a cave looking at shadows on the wall. And the other way to actually understand nature is to leave the cave and to apprehend his world of these supernatural ideal forms. So Plato becomes a problem here, Pyrrho is a problem, Aristotle is a problem — and then as we go down through the passage, religion and the supernatural and the superstitious becomes another problem. It’s beginning to look like the world against Epicurus here, isn’t it?

Cassius:

So that’s the thing to keep in mind here, because we do have some difficulty with this word “perception” here and how best to explain it. And I think the best thing we can say is: there’s quite a lot of material on the forum that you can read through, but it’s really difficult to get a handle on this because it’s presented in so many different ways.

Joshua, I’m really glad you read that excerpt, and we’ll definitely get that as a show note in the thread on this episode, because that statement that you’ve read from Wikipedia is about as clear as you could possibly be about the logical conclusion of radical skepticism from Pyrrho. And I cannot think of a position that would be more destructive to Epicurean philosophy, to life on earth, to whatever you want to call it, than to take that out to its logical conclusion — as not only Pyrrho, but others have advocated doing.

And it’s a strong strain of thought, even through current modern philosophy, as best I can determine. There’s a lot of presumption out there that any time you take a position on anything, by the very act of taking a position, you’ve ruled yourself to be a total nutcase. This is a super, super important question, I think. And I know that we all have different perspectives on these, but before I rant further — Martin, anything there?

Martin:

I’m sorry. I still have nothing to say.

Cassius:

That’s all right. These are questions that people don’t really think about a lot. At least they don’t think about them overtly. I think they have absorbed from early childhood this position that certainty is something to be avoided — that certainty about anything is the same thing as basically religious fundamentalism. There’s no middle ground between taking the position that God established it and that establishes it with certainty, and Pyrrho’s absolute skepticism saying that nothing can ever be established with certainty.

And I think that this is something that I picked up in some of the earliest readings I did in DeWitt. I think DeWitt is correct — this is one of the most important issues that Epicurus was struggling with, because he certainly did not think that there are supernatural gods that establish certainty. And at the same time, he thought and concluded that unless you have some means of controlling your experience and predicting that the sun’s going to rise tomorrow and you can order your life on a rational basis and you can use science and learning and observation and experiment to improve your condition — unless you have some hope that those things are reliable and repeatable and are going to continue to happen in the same way, then really you’re just totally a leaf in the stream, blown by the wind, and have no ability to control anything.

Moreover, as Lucretius says, I think indicative of this idea, he says that life is one long struggle in the dark. If you’re taking the Pyrrhonist view here, it has to be one long struggle in the dark. You don’t know where you’re standing, you don’t know what you’re standing on, you don’t know which direction you should go or what you should do. There’s nothing to get a handle on.

Right, right. You know, like every other word, the word “skepticism” can have different meanings. And Epicurus would endorse much of what is meant by the common everyday meaning of skepticism — that you take a very cautious approach to allegations of certainty. You seek verification through real firm evidence that is provable to you in a satisfactory way. You just don’t accept what people tell you, especially about supernatural religion and things that are counterintuitive and counter to what you’ve observed for yourself.

So in that very practical way, skepticism is exactly what Epicurus was. That’s what Lucian said in Alexander the Oracle Monger in the phrase we quoted last week about you should be skeptical to the claims of Alexander and people who allege things that just can’t be true based on your understanding of the universe.

Joshua:

Right, and it would take, he said, an Epicurus or a Metrodorus to see through the farce. So the modern idea of skepticism is we don’t accept claims that go beyond what we can verify with our senses, but what Pyrrho is saying is it is our senses themselves that are the problem. We can’t even rely upon them.

Cassius:

Right, right, right. And that’s what Plato was doing too — the senses are not reliable, and you must therefore use his logical syllogisms to prove things that go beyond what you can ever prove through the senses. And again, that’s a subject we have to be very careful in articulating. But ultimately, it’s very clear: Epicurus’s position is that the way you verify things is through the senses. Ultimately, there’s just no way to verify that something is true other than through repeated observations through the senses. If at some point down the line, you can’t tie your conclusions back to something that you can see, touch, feel, or validate in those ways through your instruments, then you haven’t proved it to be true.

And so that’s just embedded in Epicurean philosophy. And let me go ahead — I waited for this sentence in order to go back to Book 4 of Lucretius. He’s talking about illusions and he says “many more things of this kind we observe and wonder at, which attempt to overthrow the certainty of our senses, but to no purpose, for things of this sort. These illusions generally deceive us upon account of the judgment of the mind, which we apply to them. And so we conclude we see things which we really do not. For nothing is more difficult to distinguish things clear and plain from things that are doubtful, to which the mind is ready to add its assent as it’s inclined to believe everything imparted by the senses.”

“But if anyone thinks that he knows nothing, he cannot be sure that he knows even this when he confesses that he knows nothing at all. I shall avoid disputing with such a trifler who perverts all things and, like a tumbler with his head prone to the earth, can go no otherwise than backwards.”

Then Lucretius goes on and says that ultimately the senses — there’s no way to validate anything other than through the senses — “and yet allow that he knows this, that he knows nothing. I would ask, since he had nothing before to lead him into such a knowledge, whence he had the notion of what it is to know or not to know, what was it that gave him an idea of truth or falsehood, and what taught him to distinguish between doubt and uncertainty.”

So Lucretius is saying that somebody who says you can’t know anything is himself making an affirmative statement that is self-contradictory, because he’s saying with certainty that you can’t be certain of anything. So you have that sort of infinite regression of skepticism about being skeptical about skepticism.

“The rest of this can serve as the remainder… the knowledge of the truth is originally derived from the senses and the senses cannot be contradicted. What can deserve greater credit than the senses require from us? Can the ears correct the eyes or touch the ears and can taste confute the touch?” And he ultimately says that cannot be — that one sense can correct another, nor can the same sense correct itself, since an equal credit ought to be given to each. And therefore whatever the senses at any time discover to us must be certain, which goes into that issue of “all sensations are true.”

But before we just jump back into the discussion, I want to repeat this part though, that he then takes as his conclusion. He ends up saying that it’s better to just say that you don’t know rather than to take a position based on some logic that cannot be validated, because he says: “And though reason is not able to assign a cause why an object that is really four-square when near should appear round when seen at a distance, yet if we cannot explain this difficulty, it’s better to give any solution, even a false one, than to deliver up all certainty out of our power, to break in upon our first principle of belief, and to tear up all foundations upon which our life and security depend. For not only all reason must be overthrown, but life itself must be immediately extinguished unless you give credit to your senses. The senses direct you to fly from a precipice and other evils of this sort, which are to be avoided, and to pursue what tends to your security. All therefore is nothing but an empty parade of words that can be offered against the certainty of sense.”

And he elaborates on that by saying: “Lastly, as in a building, if the principle rule of the artificer be not true, if his line be not exact, or his level bear even the least to either side, everything must then be wrong and crooked, the whole fabric must be ill-shaped, declining, hanging over, leaning, and irregular, so that some parts will seem ready to fall and tumble down, because the whole was at first disordered by false principles. So the reason of things must of necessity be wrong and false which is founded upon a false representation of the senses.”

Okay, that’s the end of my quoting back from Lucretius Book 4. But the point that he’s elaborating on, I think, with great intensity — and that’s important for us today — is that, again, you understand how the senses work and use those observations from the senses as the basis for your thinking, or else you erect a structure that is just going to fall, and your whole life will be ultimately in jeopardy because you’ve given up the foundation of everything that’s important in reaching a correct opinion. That’s way too long a rant. Joshua?

Joshua:

Cassius, I’m going to take everything you just said about trusting my senses and I’m going to put that to work.

Cassius:

How are you going to do that?

Joshua:

I’m going to take a carpenter’s level and hold it up to the visible horizon, and that’s going to tell me with certainty that the Earth is flat. And when I look at pictures from NASA, I’m going to throw them out because I’m only trusting my own senses. I’m not going to trust photographs that were taken by a government organization.

Cassius:

Those are great examples of the folly that can be pursued if you aren’t careful about how you use your senses. And of course, when you do those things, Joshua, and you reach those fallacious conclusions such as that the Earth is flat — how is it that you correct your error? Do you go read a book and listen to Plato talk about logic and the perfect circle and decide, “Well, the circle is the perfect figure and the world was created by God who is perfect, so therefore we can conclude that the world must be round”? Is that the way you do it?

Joshua:

No, no. And the reason I bring this up is because I am related to people who hold these views — the view that the Earth is flat is just one example. And they really do seem to claim for themselves that they are purely motivated by what they can perceive with their own senses. But the problem with that is we were talking at the beginning here about how an understanding of the constitution of nature can be one way that we check our senses. You mentioned that a little bit ago about the round tower — or what was it, the square tower that looks round from far away?

Cassius:

Right.

Joshua:

The way that we check our senses there is just by getting closer to the tower, right? By supplementing your senses with a newer and closer observation, I guess is what I would interpret your saying.

Cassius:

Yes, yes. And so the observations that we make, including with the instruments that augment our senses, can be brought to bear on claims about our senses in one particular area. So for example, on the flat-earth issue — they’ll take a picture of the horizon at sea level and then they’ll use like software to edit the picture and put a straight line or a ruler across the picture and say, “There’s no curvature in this horizon.” Yeah, I get these pictures all the time. And it’s infuriating.

But there are other observations that you can make to check what your senses are originally reporting to you. And those other observations might eventually prove your initial assumptions wrong. And so the key — we often say this, don’t we, that when you’re considering one aspect of Epicurean philosophy, it becomes very important to consider it in the context of the entire philosophy. You arrive at conclusions by making newer observations, maybe from different angles, maybe from higher up or lower down. And maybe you can look at the stars and measure from here, and then go 500 miles the other way and then measure the stars there. It’s these newer observations that we use to test our initial sense observations about the way the world works.

Joshua:

You know, I want to emphasize part of what you said a moment ago. For example, when Pyrrho makes the assertion that everybody has different opinions about everything and that’s one reason you should conclude that nothing can ever be certain — that would be an example of, yes, it’s true, people have many different observations of things and many different opinions. But that doesn’t mean that some of those opinions are not more accurate than others and some of those opinions may not actually be accurate from a certain perspective.

When you made the example of holding something against the horizon and concluding from that that the world is flat — that is an example of an observation that you check and correct by, for instance, just walking off in that direction, or watching ships over the horizon, or getting up high enough through an airplane or a rocket ship where you can actually see the curvature of the Earth.

The essential point being that you correct your mistake through further observation. You don’t correct your mistake by a logical construction that is not tied to observation itself. It’s always observation through the senses that ultimately is what leads you to conclude that something is correct or not. All the argument in the world is not going to convince you of the correctness of something unless you can validate it with your senses at some point. We know the size of the Sun is huge through calculations, yes, but we know the size of the Sun is huge today because of astronomy and travel and rockets and the closer you get to it the bigger it becomes and things like that. What Epicurus is saying is that you can confirm many important things in life through the perceptions of the senses, and without those perceptions there’s no way to check your speculations that are not based on them.

Cassius:

You’re saying they check each other, and that is, I think, the right perspective. But ultimately, if a logical assertion that comes through a formula that is not tied to reality is conflicting with everything that you can confirm through your senses, through your instruments and through your best scientific observation, then you’ve got a situation where you need to be very, very careful about accepting the logical argument over the one that your senses produce for you.

Joshua:

Right. Now the other problem at work here is that when you hold a ruler up to the horizon you will get a straight line, and the problem is really that the whole thing is built on a faulty assumption — the assumption that the line should be curved. So when you make observations of nature you have to be aware that in a lot of these cases you are bringing your own assumptions to bear on what you’re seeing. This is how we analyze data. And because they don’t do this correctly, they arrive at badly wrong conclusions. And then when you respond to them by saying “oh look at the ships as they dip over the horizon, the bottom of the ship disappears but you can still see the top of the mast,” they’ll say, “Oh no, it’s not disappearing, it just gets smaller as it gets far away.” They have to have an answer to every objection you could make, because the assumptions about how to interpret what they’re seeing with their senses are badly wrong.

Cassius:

And I don’t think I can hit frequently enough the point that you conclude that their opinions are wrong because you have evidence that you believe shows them to be wrong. You are not just simply holding up a Bible and saying that God said the world is round — you’re not just coming up with a theory that cannot be proved by perceptual evidence. You’re saying that they are failing to incorporate other perceptual evidence that is more accurate and that actually explains in many ways the error that they’re making.

A lot of this book, before we get to this section, is talking about the work of images, and he even starts talking about things like mirrors and lots of different optical illusions. Everybody doesn’t need to be an optician or an expert in optics according to Epicurean philosophy, but the science of optics does explain to us many of these mistakes and illusions that people make when they take something on its face value and they don’t correct it.

Epicurus’s position is that the senses never lie to you — they’re never reporting an opinion that is wrong. They’re simply producing to you a set of data, and it’s up to you to evaluate the data and reach a conclusion and an opinion on it given all of the data that’s available to you. And yes, given a reasonable inquiry into what the data means and a comparison — that’s where you get these words in several places in the text about analogy and comparison and different ways of scientifically setting one observation against another to determine which one applies under what circumstances and therefore what you can expect to be repeated in the future.

The science of validating that the Earth is round, I think Epicurus would allege, is not something that you do through a logical formula. It is something that you do by perceptual data and understanding how your eyes work, what your perspective is at a particular moment, and how all those things fit together to confirm in your mind that the world is round.

Joshua:

Exactly, and one of the pieces of evidence is what I mentioned at the very beginning of this episode — stellar parallax, which they couldn’t see in the fourth century BC. But we have telescopes that can perceive this now — the movement not just of the stars rotating around the Earth’s axis in the night sky, but actually moving in relation to one another. And so that becomes an important observation that we make looking through telescopes and taking measurements, but with that observation we can test other sensory data against this one and figure out if we’re on the right track.

Cassius:

We could go on and on on this forever. I’ll try to push this through a little bit further. The next sentence that we haven’t read yet would be that when cognition and knowledge have been invalidated, every principle concerning the conduct of life and the performance of its business becomes invalidated. I don’t see that as anything other than an absolute slam against Pyrrho and any other radical skeptics who say that cognition or knowledge is impossible. And Epicurus is just saying, well, if knowledge is impossible, then you have no ability to conduct your life and performance of business in any kind of a potentially successful way.

Joshua:

Absolutely. Because what Pyrrho says is that based on his skepticism, what conduct should we adopt? We should adopt a conduct that is without views, that is uninclined toward one side or the other, that is unwavering in our refusal to choose. This is the behavior of a stone, it seems to me. Unwavering in our refusal to choose — they won’t pick one thing or another because they have no means to do so.

The idea of taking the position that none of this is knowable is just totally contradictory to what Epicurus is teaching.

Cassius:

And so the next sentence says: “So from natural science, we borrow the courage to withstand the fear of death and firmness to face superstitious dread and tranquility of mind through the removal of ignorance concerning the mysteries of the world.” Could anything be more obvious or necessary?

And this is what we’re driving to the whole time here in this entire two-week discussion we’ve been having on epistemology. This is the real point — the epistemology of Pyrrho and Aristotle, they don’t give you, they don’t tell you what your conduct should be in the face of these problems. But Epicurus said that when we understand the nature of the universe and how the senses work, you can borrow courage to withstand the fear of death and firmness to face superstitious dread and tranquility of mind. Pyrrho could not say those things. He could not make a determination as to whether or not we should fear death or whether or not the superstitions of the Greek gods were true or not.

So this is what Torquatus has been driving at the whole time, it seems to me, in our recent discussions.

And you know, some people are more comfortable with skepticism than others. I think a lot of people do sort of come to a resting point and they reconcile in their minds that it’s just not possible to come to any kind of conclusions about anything. And one of the examples I hear the most often is “everybody disagrees — how can you take the position that you’re right and everybody else is wrong? With everybody disagreeing, it’s just impossible to know. So we just need to get comfortable with the idea that it’s impossible to know anything, put all that aside and let’s go drink some wine and eat good food and have sex, whatever.” And there’s certainly an appeal to that position, but I think Epicurus’s viewpoint was that that position is not satisfactory to at least people who think like he does — people who think that it’s important to have a system of thought that organizes how you’re going to live your life and deals with that problem for you.

Martin, I have not been successful in dragging you too far into any of this today, but I need to try again. What are you thinking?

Martin:

I mean, I wouldn’t know how many words I should add to this, but I basically agree with this assessment.

Cassius:

Well, I think we’re going to find, as we do, that they’re basically making the same point over again. But this issue of the Epicurean position towards skepticism is really important. And we address it and confront it a lot of different ways as we discuss it on the different places on the internet where we discuss Epicurean philosophy. And I really encourage people to think about this question and come to terms with it and realize the implications of it.

Because I know over the years — I’ll give an example, I’ve mentioned this before — there’s a section in Diogenes Laertius where he talks about what the wise man is going to do. And he says some of the translations say the wise man will be a “dogmatist.” And the word dogmatism raises its head and it’s a word that creates lots of difficult and negative reaction. And of course, Epicurus is not taking the position that you should go out and be what we consider today to be dogmatic about everything in the world.

Joshua, especially — I’ll direct this comment to you — what we’ve not really talked about so far today is, of course, the big problem that there are many things in life that we don’t have enough information about to be comfortable in saying that our opinion is certain. And Epicurus definitely addresses that. It’s in the Principal Doctrines. I forget whether it’s 25 or not — it’s in the 20s. And we probably ought to touch on that before we start to conclude our episode today.

But he clearly understood that there are many questions in life that you don’t have enough direct observational evidence to reach a conclusion about, including the issue of atoms. He does make the point that he’s very confident about atoms being the explanation for how the universe ultimately operates. But he admits you don’t ever see an atom. You don’t touch an atom. You have to use deductive reasoning based on things that you do touch and that you do see in order to infer from your scientific observations the characteristics of the atoms.

And so you clearly have this tension between things that you have sufficient information to be confident about and things that you don’t. But in order to survive — I think that’s what he’s really getting at when he talks about how your life would just fall to the ground if you don’t take the position that you can have confidence in your senses — that you have to take a reasonable position in the end about what the senses can do for you and what they cannot do for you. You can’t say that they can do everything for you because there are many things that are beyond your ability to observe directly. But on the other hand, you can’t take the position that they can do nothing for you, because you can do many things with your senses, especially with things that are directly right in front of you.

There’s a line in Book One of Lucretius that I end up citing a lot because it says that unless you can have confidence in those things that you observe directly in front of you, it’s impossible for you to have any confidence in any opinion you might reach about things that are not directly in front of you — the things that you have to use deductive reasoning or circumstantial evidence to reach your conclusion about.

I guess that’s my legal contribution for the day — the circumstantial evidence rule. We rely on circumstantial evidence in a lot of situations to make important decisions in life on things that we don’t observe directly ourselves. We try criminal cases all the time and make all sorts of decisions based on what we think is reliable secondary evidence that leads us to be able to reach a conclusion about what’s ultimately going on. But unless you have an understanding of the way all this works, unless you take a position that there is a reasonable method for you to pursue, there’s no way for you to analyze any of it and come to any conclusions. And if you can’t do that, you’re just going to end up with the worst sense of depression and inadequacy. You’ll be frozen — like a deer in the headlights. You’ll be totally unable to go in any particular direction or have confidence in any choice that you make. It’s a very basic point, but I don’t think we talk about it probably enough in Epicurean philosophy. This has been one rant after another today. I apologize for that.

Joshua:

No, no, that was good. The important thing to keep in mind — you’ve mentioned what to do when we can’t explain a given phenomenon — but Lucretius leaves a very clear idea of one way we can proceed. And that is, even if we can’t determine what the true cause is, we can sort of reject or rule out certain things as possible causes. And one way to do that, he says, is if you can come up with a number of different natural explanations, there’s no room left for a supernatural explanation, because a natural explanation is always superior to a supernatural explanation. And so in fact, most of the latter half of his poem really has to do with precisely this — explaining how magnets work, because some people think they have little souls in them, or explaining why there’s an area of land that birds don’t go to, and it’s not because it’s been cursed by a god or anything like that.

And he goes on and on and on. This is a huge bulk of the material in that poem — how can we, even when we don’t know the real answer or we don’t have the best explanation, how can we come up with explanations that rule out certain other proposed explanations? And so that becomes really important, because otherwise you’re left with Pyrrhonism, and our unwavering refusal to choose one explanation or another, and our adoxastoi — the view that we should be without views.

Cassius:

Again, I’m very glad you took the time to find that quote and introduce it today.

And while you were talking, I found the locations in the Principal Doctrines that I should have immediately known. Principal Doctrine 23 starts it off: “If you fight against all sensations, you will have no standard by which to judge, even those of them which you say are false.” And I think that’s almost exactly the point that Lucretius was making and that Torquatus has made here today. If you say that the sensations are unreliable, if you fight against them, then you have no standard by which to judge, even those sensations which you say are false. Like, everybody knows that the oar is not bent when it’s put in the water. But if you say that all sensations are unreliable, then you’ve deprived yourself of the ability to pull the oar out of the water and observe it in closer context and realize that it’s not bent. You’ve deprived yourself of any standard by which to make any conclusions at all.

And that’s pretty clear in Doctrine 23 there. And then 24 is one of the longer ones and probably one of the more labyrinthine in the way he words things, but Principal Doctrine 24 I would urge everybody to read in detail as well. Josh, I don’t know if you can find it while we’re talking, but it does make many of these very same points.

“If you reject any single sensation…” — in other words, every sensation, even the ones that make the world look flat to you, you need to understand is something that your eye has presented to you, and you ultimately need to accept it as a presentation that is not intended to deceive you. The eyes themselves are not deceived. It is just what occurs under that particular set of circumstances.

“If you reject any single sensation and fail to distinguish between the conclusion of opinion as to the appearance awaiting confirmation and that which is actually given by the sensation or feeling or each intuitive apprehension of the mind, you’ll confound all other sensations” — which I think is a lot of words very difficult for people to follow. But the point being that you have to distinguish between what the senses have reported to you and the conclusion of opinion, which means your opinion about what the senses have reported to you. Just because they’ve reported some fact to you does not tell you that the world is flat or round based on just a single observation. And so you have to distinguish between a single observation versus an opinion that you have confirmed through repeated observations — “and then you will confound all other sensations as well with the same groundless opinion so that you reject every standard of judgment. And if among the mental images created by your opinion, you affirm both that which awaits confirmation and that which does not, you will not escape error since you will have preserved the whole cause of doubt in every judgment between what is right and what is wrong.”

I don’t think it’s possible to make sense out of that without looking at it closely and studying exactly what he’s saying and thinking about each passage, maybe even comparing some different translations to get the sense of it stronger. But it seems pretty clear to me at this point that what he’s simply saying is that you create opinions, you create mental images based on your observations. And if you don’t keep separate those opinions which you’ve confirmed from those opinions which you really have not confirmed — you’ve only seen it a couple of times, you’ve only seen it under limited conditions — if you say that your superficial judgment is the same as your long-considered and long-experienced conclusion from many years of study, and you say those two are the same thing, then you’ve confused yourself.

So again, Doctrine 24 requires a lot of thought and reading to get out of it what probably is there, but it’s basically the same point we’ve been making today. The same point I’ve been droning on about today. And especially since I’ve not been successful in getting Martin to weigh in as much as I would like to. But we’re probably beginning to come to the end of a normal-length episode today, and so what do we traditionally do in order to get the most reliable conclusion from the episode but to first go to Martin and ask him for his concluding thoughts?

Martin:

Yeah. Sorry, it seems I cannot come up with anything, so I pretty much agree with what we read and with a lot of what you talked about it, but I couldn’t now come up with something like a short conclusion of that.

Cassius:

Okay, I’m going to risk going overboard again — and continuing another overboard statement I made last week — by saying that I think that Martin’s example to us is profitable even when he doesn’t elaborate any more than he just did. Because I think a scientifically minded person, this is going to be second nature for them. They’re going to know that they have to test and experience and observe over time to make sure that they’ve got their observations correct, and it’s going to be second nature. You’re not going to easily make the mistake of thinking that you can just read a book or apply a formula and that your observation is necessarily going to conform to what the book says or what the formula predicts. You learn which formulas to trust and which ones are going to have more variables in them that are going to be more difficult to predict the result.

And so, again, Martin, I appreciate your comments, and to some extent even when you don’t comment as much as I might like, I think your experience is something that people should consider — this should become second nature. A rational degree of skepticism that is prudent and that still allows for some conclusions to be reached in those things which can be established seems to be obvious and seems to be the position that a lot of people end up with after thinking about it from a common sense perspective.

But if you’re a Pyrrhonist, you don’t end up there. You end up with this crazy notion that nothing can be proved, that nothing can be established. And rather than devoting yourself to a life of science and improvement and happiness like hopefully many of our scientists do today, you would just, in my view, lapse into total paralysis because there’d be no reason for you to do anything.

But Joshua, what do you think?

Joshua:

Yeah, I don’t know how to kind of sum up everything we’ve been saying. It’s kind of just repeating ourselves one time after another.

There is a story that comes to my mind, and this comes from Walden by Henry David Thoreau. He said that there was a traveler who was on the edge of a swamp, and there was a boy nearby fishing. And the traveler asked the boy if the swamp before him had a hard bottom. And the boy replied that it did. But presently the traveler’s horse sank in up to the girths, and the traveler observed to the boy, “I thought you said that this bog had a hard bottom.” To which the boy replied, “So it has, but you have not got halfway to it yet.”

So what is the point of that? I guess it’s that while our senses may appear to fail us in sort of an early evaluation, when you really dig in deeper and you consider multiple observations against one another, you’re going to get to the ultimate position, which is that our senses are fundamentally reliable. I don’t know if the story tells that, but that’s just something I thought of.

Cassius:

I think that’s pretty good, actually, Josh. You know, another way to say it would be that you may not immediately be able to come to a conclusion that you’re satisfied with, but you don’t ever abandon your method of relying on the senses. You don’t just walk away from them and say, “Well, I’m going to go with the supernatural option,” or “I’m going to go with the idea that nothing is reliable, and so therefore I’m going to sit home and do nothing.” You don’t take either of those two extremes in those positions where the information that you have is insufficient to satisfy you.

You do exactly what Lucretius is saying in Book 4, and you say that there are multiple possibilities. And Lucretius is saying what we did talk about today — that it’s better for you to be wrong than for you to just give up all confidence in your senses. And in most cases, it’s not necessary for you to take a position that’s so wrong that you’re necessarily adversely affected by it.

But basically where he goes with it is: if there are multiple possibilities that are consistent with the evidence and you don’t have enough information to choose between those multiple possibilities, then you be honest with yourself and you admit, “There are multiple possibilities. I don’t know which one is right, but these are the possibilities, and I’m just going to live with this until I can get more information and choose between the two.” You don’t reject multiple reasonable possibilities, nor do you accept supernatural possibilities as equal in degree to the things that are not supernatural. You simply be honest with yourself. You hold tight to your confidence in your senses, which got you to where you are in the first place, and you move forward with confidence in those senses so that you don’t collapse, so that you don’t run off the edge of those precipices.

Many commentators think that these ancient philosophers were very concerned about tripping over dogs in the street or walking off of cliffs and things like that, much more so than you would think today. But I guess they are good examples of common hazards that you run into and that you are trusting your senses in everything that you do, and you cannot let a philosophic error lead you into concluding that your senses are going to lead you astray on the more important things in life.

Because everything ultimately is based on your confidence and your ability to understand the constitution of the world and how your senses operate to allow you to interact with it.

We will totally change our direction next week and move past natural science and use it to establish that of all the tools towards happy living which the wise man is going to pursue, none are of more importance than friendship. And why that’s the case and the different explanations that Epicurus gave in support of it.

So with that, why don’t we close for the day and we’ll come back next week. Thanks for being here today. Bye.

Martin:

Thank you.