Episode 024 - The Swerve Part One: As A Producing Force of Nature
Date: 06/27/20
Link: https://www.epicureanfriends.com/thread/1599-episode-twenty-four-the-swerve-part-one-as-a-producing-force-of-nature/
Summary
Section titled “Summary”Episode 024 introduces the swerve (the slight, unpredictable deflection of atoms from their paths) in the first of two episodes on the topic. Elaine reads Daniel Brown’s translation of the introductory passage, which contains two main elements: first, a rebuke to those who think matter cannot organize itself without divine guidance — with a striking phrase, “pleasure, the deity and great guide of life,” identifying pleasure as the force that nature uses to impel living things — and second, the first presentation of the swerve itself. A translation comparison reveals that Stallings’s verse translation omits the pleasure reference entirely, while Martin Ferguson Smith preserves it as “divine pleasure, the leader of their life, their escort who entices them through the acts of Venus.” The passage also notes that Lucretius inserts a reminder that the world is “faulty and imperfect” as a standalone argument against theistic creation, independent of atomic theory.
The physics discussion is anchored by the problem of “downward” motion in a universe with no center: Martin confirms this is an acknowledged error in Epicurean physics traceable to the lack of a proper theory of gravity before Newton. The flat-earth question is briefly examined — Martin notes the possibility that Epicurus’s downward motion was consistent with flat-earth thinking in some ancient sources, though other Greeks already knew the Earth was roughly spherical. Cassius raises the point that even if atoms all fall at the same rate, nothing on the other side of the Earth would fall away, which Martin confirms: they would hover, not fall off. The David Sedley article “Epicurus’ Refutation of Determinism” is discussed at length. Cassius had recalled Sedley arguing the swerve was an afterthought added for free will, but Martin corrects this: Sedley argues Epicurus developed the swerve first for cosmogony (as the mechanism to start atomic collisions), and only later was it interpreted as defeating determinism. Martin’s own view goes further: the swerve was actually unnecessary for cosmogony in proper physics (interaction fields are sufficient), but it is genuinely important for defeating determinism.
The episode’s closing discussion compares the Epicurean swerve to Heisenberg’s uncertainty principle and to the measurement uncertainty embedded in classical physics even before quantum mechanics. Martin notes that Heisenberg himself acknowledged an uncertainty principle in classical physics arising simply from the limits of measurement instruments, and that the quantum mechanical uncertainty goes beyond this — but the Epicurean swerve is not a precise analog to either, because the quantum uncertainty arises from interaction (not from isolated particles spontaneously deflecting). Two scholarly articles are recommended: A.A. Long’s “Chance and Natural Law in Epicureanism” (which argues the swerve is deliberately kept small enough not to make the universe chaotic, and notes that Cicero never argued the swerve made Epicurean physics self-contradictory) and David Sedley’s “Epicurus’ Refutation of Determinism.”
Transcript
Section titled “Transcript”Cassius: Welcome to Episode 24 of Lucretius Today. I’m your host, Cassius, and together with my panelists from the EpicureanFriends.com forum, we’ll walk you through the six books of Lucretius’ poem and discuss how Epicurean philosophy can apply to you today. Be aware that none of us are professional philosophers and everyone here is a self-taught Epicurean. 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. Before we start, here are our three ground rules. First, our aim is to bring you an accurate presentation of classical Epicurean philosophy as the ancient Epicureans understood it, which may or may not be the same as what you hear about Epicurus at other places today. Second, we aren’t talking about Lucretius with the goal of promoting any modern political perspective — Epicurus must be understood on his own, and not in terms of competitive schools which may seem similar to Epicurus but are fundamentally different and incompatible, such as Stoicism, Humanism, Buddhism, Taoism, Atheism, or Marxism. Third, the essential base of Epicurean philosophy is a fundamental view of the nature of the universe. When you read the words of Lucretius, you’ll find that Epicurus did not teach the pursuit of virtue, or luxury, or simple living, as ends in themselves, but rather he taught the pursuit of pleasure. From this perspective, it is feeling which is the guide of life, and not supernatural gods, idealism, or virtue ethics. And as important as anything else, Epicurus taught that there is no life after death, and that any happiness we’ll ever have must come in this life, which is why it is so important not to waste time in confusion. Now let’s join today’s discussion with Elaine reading the text.
Elaine: “But some object to this, fools as they are, and conceive that simple matter cannot of itself, without the assistance of the gods, act so agreeably to the advantage and convenience of mankind as to change the seasons of the year, to produce the fruits, and to do other things which pleasure, the deity and great guide of life, persuades men to value and esteem. It could not induce us to propagate our race by the blandishments of tender love, lest the species of mankind should be extinct, for whose sake they pretend the gods made all the beings of the world. But all conceits like these fall greatly from the dictates of true reason. For though I were entirely ignorant of the rise of things, yet from the very nature of the heavens and the frame of many other bodies, I dare affirm and insist that the nature of the world was by no means created by the gods upon our account. It is so very faulty and imperfect, which, my Memmius, I shall fully explain.
“But now let us explain what remains to be said of motion. And here, I think, is the proper place to prove to you that no being can be carried upwards or ascend by any innate virtue of its own, lest by observing the tendency of flame you should be led into a mistake. For flame, you know, is born upwards, as well as when it begins to blaze as when it is increased by fuel. So the tender corn and lofty trees grow upwards. Nor when the flames aspire and reach the tops of houses and catch the rafters and the beams with a fierce blaze — are you to suppose they do this by voluntary motion and not compelled by force? It is the same when blood gushes from a vein: it spouts bounding upwards and sprinkles all about the purple stream. Don’t you observe likewise with what force the water throws up the beams and posts of wood? The more we plunge them in and press them down with all our might, the more forcibly the stream spews them upwards and sends them back, so that they rise and leap up at least half their thickness above the water. And yet, I think, we make no question that all things as they pass through empty void are carried naturally down below. So likewise, the flame rises upwards, being forcibly pressed through the air, though its weight by its natural gravity endeavors to descend. Don’t you see the nightly meteors of the sky flying aloft and drawing after them long trains of flame, which way soever nature yields a passage? Don’t you see also the stars and fiery vapors fall downwards upon the earth? The sun, too, scatters from the tops of heaven his beams all round, and sows the fields with light. Its rays, therefore, are downward sent to us below. You see the lightning through opposing showers fly all about, the fires burst from clouds — now here they’re engaged; at length the burning vapor falls down upon the ground.
“I desire you would attend closely upon this subject and observe that bodies when they are carried downward through the void in a straight line do it some time or other, but at no fixed and determinate time, and in some parts of the void likewise but not in any one certain and determinate place of it, decline a little from the direct line by their own strength and power — so nevertheless the direct motion can be said to be changed the least that can be imagined. If the seeds did not decline in their descent, they would all fall downwards through the empty void like drops of rain. There would be no blow, no stroke given by the seeds overtaking one another, and by consequence nature could never have produced anything.
“But if anyone should suppose that the heavier seeds, as they are carried by a swift motion through the void in a straight line, might overtake and fall from above upon the lighter, and so occasion those strokes which produce a genial motion by which things are formed, he is entirely out of the way and wanders from the rule of true reason. Indeed, whatever falls downward through the water or through the air must necessarily have its speed hastened in proportion to its weight, and for this reason, because the body of water and the thin nature of the air cannot equally delay the progress of everything that is to pass through it, but must be obliged to give way soonest to heavy bodies. But on the contrary, mere empty space cannot oppose the passage of anything in any manner, but must, as its nature requires, continue forever to give way. Therefore, all things must be carried with equal force through a void that cannot resist, for there several weights be unequal, so that the heavier bodies can never fall from above upon the lighter, nor occasion those blows which may change their motions, and by which all things are naturally produced. It follows, then, that the seeds do every now and then decline a little from a direct line in their descent, though the least that can be imagined, lest we think their motion were oblique, which the nature of things refutes.
“For we see this as plain and obvious, that bodies by their natural gravity do not obliquely descend when they fall swiftly from above through a void, which you may discover by your eyes, but that nothing declines in its descent ever so little from a direct line — who is so sharp-sighted as to distinguish?”
Cassius: Thanks, Elaine. There’s a lot of text here. What are you thinking?
Elaine: It’s — I’m interested to see what Martin says. And for me, I’m having to work to see this even minus basic physics, so I don’t even know what does “weight” mean if you don’t have gravity.
Cassius: Before we go too far into the specific physics, let me say something that I wanted to say about this particular block of text. I think this is the beginning of the introduction to the discussion of the swerve. And there are a couple of things in this block of text. This first paragraph — there is a lot in it that I think is more general, that we need to discuss and maybe look at a few of the words in particular. Because there’s one phrase in that first section — in the Daniel Brown it says, “Pleasure, the deity and great guide of life.” That’s a phrase that I think has a lot of significance to it and that I tend to go back to a lot. Munro calls that “divine pleasure, the guide of life,” which I think is fairly close to the Latin. And then Bailey translates that a little bit differently — kind of splits it up. He talks about “which divine pleasure wins men to approach while she herself, the leader of life.” So he goes a little bit differently, but this is one of the phrases in Lucretius that really is a direct statement that pleasure is the leader of life. Sometimes we don’t have it stated so directly.
Cassius: Anyway, I’d like for us to talk about that first passage. And then in summary — a lot of the rest of it is introducing the idea that the swerve exists, that it occurs only to a very small degree. But mainly the point I wanted to raise is that the swerve in Lucretius has two major functions. This first part that we’re discussing today is a discussion of how the atoms first collide, rather than falling straight down, which leads the universe to be formed in the first place. So next week we’ll discuss the second function, which is the free will aspect of it. In this first introduction part, he’s simply talking about how they deviate ever so slightly from a straight line, but it’s enough to bring them into contact to form the collisions that cause everything else to occur. So what line numbers are we on? It’s not going to be the 1743 line numbers. It’s going to be about line 170.
Cassius: I think the ending of the first paragraph is also worth looking at. Which part? About the last sentence — that Lucretius insists that the nature of the world wasn’t created by gods?
Elaine: Yes, that whole first paragraph is a very general summary of a lot of the positions, and maybe the direction we’re going in, to explain again the ultimate meaning of why we’re talking about all this stuff.
Cassius: I think his words “faulty and imperfect” are also sort of indicative of the nature of this world. There’s so much in that first paragraph. Elaine, did you find it in Martin Ferguson Smith? Maybe we should read this one.
Elaine: Okay, well I was actually looking at Stallings, and I don’t even see anything mentioned about pleasure. It should start with: “that certain people, ignorant of matter, are at odds with this and think that it is impossible without the gods for nature to create the crops and alternate the seasons in such convenient accordance with our human reasons.” It doesn’t mention pleasure. I can’t believe that our poet did not do that. What is up with that?
Cassius: Let’s see — let me go to find Martin Ferguson Smith. It’s hard to believe that it’s not there. Okay, so Martin Ferguson Smith. Line 168. Yes, go ahead.
Elaine: “And yet, in defiance of these facts, certain theorists, ignorant of the properties of matter, believe that in the absence of divine direction, nature could not conform so obligingly to human requirements by changing the seasons of the year, by producing crops, and indeed all the other gifts to which mortals are beckoned by divine pleasure, the leader of their life, their escort who entices them through the acts of Venus.”
Cassius: That’s nice. Right. So, wow. Why did Stallings do that? That is so interesting.
Cassius: Well, Charles, are you seeing the same thing in Stallings?
Charles: Well, looking at that — the rest of what Elaine didn’t read is: “who entices them through acts of Venus to reproduce their kind so that the human race may be saved from extinction. And then it’s supposing that the gods have arranged everything for the benefit of humanity. These thinkers have obviously deviated far from the path of sound judgment in every respect. Yeah. Even if I had no knowledge of the primary elements of things, I would venture to deduce from the actual behavior of the sky and from many other facts, evidence, and proof that the world was by no means created for us by divine agency. It is marked by such serious flaws. Later, Memmius, I will make this plain to you, but now I will complete my explanation of the movement of atoms.”
Cassius: So that — I like his version of it. Very clear there. Yeah. I like the Martin Ferguson Smith — it’s a poetic passage here, so it’s kind of disappointing that the poetry translation didn’t run with that. Charles, are you seeing that too — that Stallings has left it out?
Charles: I have the Stallings copy and yeah, there’s not a single mention of pleasure, or propagating the species, or anything.
Cassius: That’s amazing. Well, I know sometimes people use different orderings of the text, but I would have thought that Stallings was using basically the same thing Martin Ferguson Smith has. I don’t understand that either.
Martin: Yes, he has previously.
Cassius: We could almost spend the whole day today talking about that paragraph. So Martin Ferguson Smith is saying that he’s referring to Stoics and Platonists. Yeah — Plato and the Stoics is who he’s referring to. “And yet, in defiance of these facts, certain theorists” — and then he puts a footnote and says he’s talking about Plato and the Stoics, which probably is correct. And so this is the argument that matter of itself cannot come together and act in ways that produce us and the seasons of the year and all that other stuff — that the gods have to be guiding matter in order for it to occur. Which gets you into the argument about whether matter alone can be active, or whether there’s some kind of spiritual dimension or some other outside force that controls it.
Cassius: But then that’s when he adds in “the things which pleasure, the deity and great guide of life, persuades man to value and esteem.” So do y’all agree that he’s putting pleasure in the role of what everybody normally thinks that God does, to guide living things?
Elaine: Yeah.
Martin: Yeah.
Elaine: It’s a bit of a personification, but Lucretius is known for that.
Cassius: Right. Okay. Well, another comment I wanted to make on that paragraph was that “lest conceits like these fall greatly from the dictates of true reason” — meaning that, again, true reason is what he’s considering Epicurean philosophy to be. He’s not slamming reason in general. He’s saying true reason. Reason based on observation, right?
Elaine: Practical reason.
Cassius: I see Martin Ferguson Smith says “sound judgment.”
Elaine: Yeah, that’s a good one. Sound judgment. I like that.
Cassius: Okay. And then: “for even if I were entirely ignorant of the rise of things, I dare affirm that the nature of the world — ” you don’t even need, he’s saying, to have this atomic theory to realize that the world is not made specially for humanity, because it is so faulty and imperfect.
Elaine: Yeah. That’s an independent argument that you often see.
Cassius: Well, we still see that today — arguing against, “if I’d have been God, I would have made it better. If you’re really omnipotent, what the heck?” So he’s interrupted his atomic discussion to insert this, which does give us, I think, a good reminder of where we are and where we’re going.
Cassius: Okay, well, now let’s get back to the physics. So this next one is about him observing tendencies of things to go upwards — the flames, the arterial blood, and the buoyancy of things in water. Those three observations. But he lets us know in the beginning that he said, lest by observing this, don’t get led into a mistake. You’re going to observe these — don’t draw a wrong conclusion. So this is not a standalone paragraph here.
Elaine: Yeah, that’s a good point. Lest by observing the tendency of flame you should be led into a mistake. So this is a statement that you can observe something and yet be led into a mistake.
Cassius: While every observation has to be considered, you obviously have to test your observations against other observations. And not everything behaves like flame does.
Elaine: Or it’s not even that not everything behaves like flame does — even flame, because in the next section he explains that its natural tendency is to descend. He’s saying the flame is being forcibly pressed through the air upwards. That it’s not what it looks like to you either.
Cassius: So in talking about lightning and the stars and so forth, he’s using examples of fire that doesn’t always go upward. Right. Okay, well then the next section is where he introduces the swerve. “At no fixed and determinate time, and in some parts of the void likewise, decline a little from the direct line by their own strength and power. The direct motion can be said to be changed the least that can be imagined.”
Elaine: Okay, so I am not understanding how you have downward motion in a universe with no center.
Martin: Exactly. So this is one of the things which are inconsistent in Epicurean physics. This is also in the Letter to Herodotus wrongly explained.
Cassius: Yeah.
Martin: It just doesn’t make sense. And this is because Epicurus, and also in the subsequent centuries, the people just didn’t have the proper theory of gravity. And that was only Newton who came up with the right approach. And before that, no one — I didn’t see any consistent explanation of gravity which happened before Newton.
Cassius: So Martin, wouldn’t — even if you didn’t know that — I still don’t understand why he would think there was a direction “down” if there’s no center and no edge.
Martin: Yeah, because at Earth — the only place we can observe, at that time it was only on Earth — and on Earth everything looks like, at the place where you are, where you observe, you see everything goes down. And this can be used as a reason. I’ve seen this in at least one place proposed as a reason for the flat earth. I have doubts on this one, but it could possibly be the case — which is a bit surprising, because other Greeks knew at that time already that the Earth is approximately a sphere. So that means from those other Greeks, Epicurus would have been aware that there is no absolute up and down because of the spherical shape of the Earth.
Cassius: Martin, it’s been my understanding they knew that the Earth was a sphere — maybe to some extent based on the eclipses of the moon, when you see the shadow of the Earth. But even though the Earth might be a sphere, that doesn’t mean you could stand on the other side of it without falling off. If everything is falling downward through the universe — if you want to use the word “down” or “in the same direction” — it wouldn’t be like the other side was flat, but you could still fall off the other side.
Martin: Because the Earth would fall with the same speed, so that means they would just hover.
Cassius: That’s a good point. But they would not experience this gravity we have.
Cassius: Right. And we kind of covered this maybe in an earlier section, but I do get the impression that the commentators think that Epicurus thought that you could fall off the other side. Now maybe you’re right about what you just said — that if everything’s falling then you wouldn’t fall off, because you wouldn’t move any faster than the Earth is. That’s probably a very good point, Martin. Maybe that’s the explanation of why you could be existing on the other side of the Earth even in Epicurus’ theory — because everything’s falling the same speed. And that’s what he’s saying here — that just because something might be heavier, it’s not going to fall any faster. So you’d have to integrate all that to kind of make sense of it. But I haven’t seen the allegation that he was a flat-earther. But I’ve seen the allegation that that’s why he’s saying people on the other side of the Earth would be walking upside down — in some way, that he thought that on the other side of the Earth the same force of downward motion would be carrying people down.
Cassius: I never got the impression from the Letter to Herodotus that Epicurus was a flat-earther, but I know it’s been discussed before in Lucretius.
Elaine: I guess you have to be careful about what the definition of flat-earther means — because I have a picture of something looking like a frying pan, where you really do have a flat bottom to it.
Cassius: I don’t know what the right answer is here, but I don’t get the impression he took that position. But I do get the impression that he thought you might be able to fall off the other side. He knew that the Earth was not the center of the universe, but he didn’t know that there was a gravity field within a particular planet that would bring everything to the center of that planet.
Cassius: I’m not sure we were going to focus on this, but in reading recently this article by David Sedley called “Epicurus’ Refutation of Determinism” — there’s some material in there that would be relevant to somebody who really wanted to read into this. Because Sedley, who is I think a well-respected expert, takes the position that what we’re seeing here in the swerve is something he alleges — his theory is that Epicurus developed this later in his theorizing. And to some extent it’s grafted back in. Because Sedley alleges that there was never really any need for Epicurus to come up with the swerve in order to get the universe started — that basically all you really needed was a couple of atoms at one particular time. And we talked about this last week a little bit, Martin — whether once you got everything bouncing around, would the bouncing continue indefinitely and be enough to cause the formation of the universe? And maybe the question is how often do the atoms really need to swerve in order to cause things to happen and come together and bounce apart and so forth. But Sedley’s conclusion is that Epicurus was more interested in the swerve because of the free will argument — to break free of the billiard-ball view of determinism. I don’t know whether that’s true or not, but somebody wanting to read into all of this — Sedley’s article was very interesting on that particular point.
Martin: Oh, by Cassius, I think you have it the other way around. So I just read the article, and my impression is — what’s the other way around — that Epicurus used the swerve for the cosmogony, and only later it was then also interpreted that it helps with determinism. Because that demonstrates that Epicurus thought of something we call now emergent properties — and even though they somewhat depend on the arrangement and movements of elementary particles, they are something of a higher-level quality which is not directly visible in these elementary particles.
Cassius: Martin, if you’ve read that article, I feel confident you were more precise in reading it than I was, because I intended to read it several times and I’ve only been able to skim through it once so far. But you got the idea that he thought that some part of the swerve was developed later in Epicurus’ reasoning?
Martin: No, no. Epicurus developed the swerve to explain cosmogony, because the problem is that Epicurus had no proper idea about interaction, and this keeps him stopped, so to say — he knew his first law, and he cannot move any further, and then there will be no arrangement of particles. And so then he came up with the swerve. So from my perspective, he came to the swerve for all the wrong reasons, because the swerve is not necessary for cosmogony. But I still feel it’s much more important to defeat determinism, because I found this reasoning with emergent properties not convincing. But there I may have a deeper problem with the physics understanding, because I have the same problem with statistical properties in thermodynamics, where I basically see physicists — physics professors — claim the same thing. But the formula clearly shows that we just sum up all the elementary particles and then we come to things like temperature. So that means these emergent properties are directly linked to these elementary particles and their movement. So this tells me that this does not defeat determinism.
Cassius: Elaine, be sure to jump in if you want to say something. But I have one more thing to add, Martin — on what you just said. Did you pick up in the Sedley article that he thought it was very significant that this passage we’re talking about today included the last sentence: “but that nothing declines in its descent ever so little from a direct line — who is so sharp-sighted as to distinguish?” Do you remember Sedley talking about that? And did you have any comment on that? Epicurus seems to be wanting to — I don’t know whether “emphasize” is the right word — but Epicurus is pointing out here that yes, the swerve exists, but we do not have the capacity to see it swerve. And in fact Sedley referred to some medieval or Newtonian-era person who made the same point. Do you remember that part of the article?
Martin: I don’t remember this one.
Elaine: So that last line kind of surprised me too. I mean there’s a lot in this because — okay, I think what’s catching me up is that Epicurus got so many things startlingly right that it throws me off when I see things that of course he just didn’t know yet. So that’s fine — there’s a lot we don’t know yet. But it makes it a little bit difficult. It doesn’t go with my view of him.
Elaine: So this last line — “but that nothing declines in its descent ever so little from a direct line, who is so sharp-sighted as to distinguish?” — you know, this is a contrast with some of the prior sections that we’ve read. And I wish I knew exactly where, but in the first book, where he distinguished between behavior of the seeds — the elementary particles — and the visible aggregates. Here he’s not doing that. He’s acting like a leaf falling down from the tree is supposed to be showing this swerve. That surprises me.
Cassius: See, I wish I were much more on top of this to be able to address it with more authority. But that’s why I found that article so interesting, Elaine. Because I think Sedley ends up concluding that this last sentence that you’re talking about is maybe one of Epicurus’ most brilliant and important things in this section. Because I think he’s relating it — I don’t understand it well, and I don’t remember it very well, what Sedley was arguing — but I think he was relating it to the issue that we don’t have the capacity to see an atom. So I think maybe it’s related to the fact that if we know we can’t see an atom, by definition we cannot see it swerve. But nevertheless, even though we cannot see the atom or its swerving, we do conclude that it exists.
Elaine: We can see its effects.
Elaine: Just thinking about how the swerve relates to — is it a comparison of dust particles in a stream of light in a dark room, right?
Cassius: Yeah.
Elaine: I guess what, Cassius — I think what’s messing me up is: he’s in this section here, he says “it follows that the seeds do every now and then decline a little.” Okay, so we’ve got that sentence where it’s clearly talking about the seeds. This next sentence — “for we see this is plain and obvious that bodies by their natural gravity do not obliquely descend” — that’s not seeds. And then the next line doesn’t clearly refer back to seeds. It sounds like the antecedent for that is “bodies,” because he doesn’t reintroduce the term “seeds.” But I’m hoping he’s talking about seeds and not that there’s some invisible declination of macroscopic bodies.
Elaine: You understand what I’m saying?
Cassius: I do, yeah.
Martin: But it should be the same, because if a particle which is bound inside a leaf swerves, then the whole leaf will swerve as well — but an even much smaller amount than that particle wants to swerve. So that means once a particle swerves, also the bigger bodies can swerve. But both motions are too small for us to detect.
Elaine: Well, that’s only if everything is going down. Okay, I see that if everything’s going down that would have to happen. But swerving is not happening in the same direction as the leaf — the movement of elementary particles is not happening in the same direction as the leaf. So that’s not actually — that’s not true.
Martin: No, no. But the average movement goes — of course the individual particles move with much larger speed in all directions. But right, because they are forced into their body, they’re held together by the interaction. So their average speed is like from that falling leaf. And there should be, if there’s no wind, a straight line down.
Cassius: While we’re thinking about that, the Martin Ferguson Smith version of that might be slightly more clear: “For it is a plain and manifest matter of observation that objects with weight left to themselves cannot travel an oblique course when they plunge from above — at least not perceptibly. But who can possibly perceive that they do not swerve at all from their vertical path?”
Cassius: So I don’t know — he’s wrestling with the same issue that I think Elaine is talking about. I think this is where Sedley was making the point that he is saying: even though when we look out the window and see leaves falling to the ground, they appear to fall — obviously leaves are going to move around in different directions — I guess that’s what you’re raising, Elaine: was he making an analogy to leaves, which don’t fall straight down most of the time?
Elaine: I was making a distinction between the subatomic action and the leaf, and I’m trying to still think about what Martin’s saying. I’m not sure we’re talking about the same thing, because obviously, obviously all the particles in the leaf are going with the leaf — they’re in the leaf. But I think there’s more to it, because the individual ones swerve, and the sum of the movements are different from things.
Martin: Yeah, also to be clear about what I said — I tried to say that this is in Epicurus’ false physics, okay? From the actual physics, because it’s wrong from the start. Whatever you say.
Cassius: Okay, all right, all right.
Elaine: Yeah, but of course he doesn’t know — he doesn’t know the difference between mass and weight.
Cassius: Yeah. Because we’re missing gravity. So there’s just so many dimensions of — gravity.
Martin: So yeah. So he may — rather the other way around — he does not understand inertia. He does not really understand this inertia concept here, or mass. But another thing to this last question: so this is basically the empiricist standpoint which can be used to introduce indeterminacy already in classical physics, because we have some measurement uncertainty. So that means even classical physics already has an uncertainty principle — it’s just that it doesn’t show up as an uncertainty relation, because no principled limit which we cannot be below in our sensitivity could be given before quantum mechanics. So that means what he presents here is this reasoning to assign uncertainty already to classical mechanics from an empiricist viewpoint.
Cassius: Martin, I think that’s an important point. For somebody who’s more simple-minded and less physics-oriented than you are — would it be correct if I were to say that what you’re saying is that because our rulers or our measuring devices are only so accurate, we necessarily have to admit that any incremental change that is less than our smallest increment on our ruler — we don’t know exactly — and then the consequence will carry on to the future? What would happen in the future?
Martin: Yes, uncertainty will attach to the future. And so you’re saying that even before Heisenberg ever came up with any kind of a theory — that people starting to think about it hard enough have to realize that below the level of our precision, we don’t know what’s going on at that level.
Cassius: I mean, for me it’s not fully convincing, but this is one way to argue if we take empiricism seriously. But just to look again at the whole perspective: with the atoms, Epicurus came up with a way to in principle explain the world with the help of postulating elementary particles. And the same thing now — from his false theory, he had to save the thing by introducing the swerve. But we cannot detect the swerve at that time, so he could not directly observe it. But because things add up the way we see them, then he postulates: this can be explained by introducing the swerve.
Martin: Martin, what do you think about — I’ve seen many people make comments about this part of the text that we’re reading, and they focus on the words about how the swerve is, and yet, “not more than the least possible.” The fact that Epicurus is seemingly emphatic that we deduce that the swerve exists, but that its measurement is extremely small — the deviation is extremely small. Do you have any comment about that aspect of it?
Martin: Of course you do not want to make it unnecessarily big. So I mean, it’s like basically the whole philosophy: we try to minimize what we need to believe, and we rely on what we know. So that means the philosophy is based on knowledge, and only for this one we need only a minimized set of beliefs. And this is an analogy here: in order to explain the way things are at a macroscopic scale — so we do not detect the swerve — but in order for things coming together we need something. Based on the false physics, that means the swerve is somehow there. And simply because we cannot directly detect it, it’s safer to assume it’s just the smallest possible amount.
Cassius: Yeah. Yeah, Elaine, do you have any thought about that part of it?
Elaine: I think what Martin is saying makes sense.
Cassius: Okay, all right. Well, related to that — another article that I really refer to frequently on the topic of the swerve is an article by A.A. Long called “Chance and Natural Law in Epicureanism,” and I raise that because it always seems significant to me. His argument in that article is that the swerve is potentially something that would totally disrupt the rest of the philosophy if it made things so unpredictable that the universe was chaotic — that it changed so quickly and so impulsively and so unpredictably that we couldn’t even — it wouldn’t make any sense whether we looked and saw whether there’s a canyon or not, because the canyon might not be there the next moment.
Cassius: And so his argument there was that if the swerve were that profound in effect, then Cicero and the other classical opponents of Epicurus would have said that your swerve destroys your whole argument about how the atoms are the force of regularity in the universe. But they did not make that argument. A.A. Long says that it’s not recorded in Cicero or any of the other opponents that they went so far as to say that the swerve turns everything upside down. They thought — Cicero argued — that the swerve made no sense, that it doesn’t answer anything, because you still have to then answer — from Cicero’s point of view — where does the swerve come from. But they did not seem to argue that Epicurus was creating a force of indeterminacy so strong that the universe would become chaotic.
Cassius: There are several points here that are very difficult to expand on for somebody who’s not an absolute expert, and I certainly don’t claim to be an expert on all of this. But for somebody who wants to read into it, there’s a lot of material that’s very interesting.
Martin: Yeah, another remark here. So this explanation on the swerve also tells how it’s different from the uncertainty in quantum mechanics. So there’s a strong analogy, but not more, because formally the Epicurean swerve — so in his concept, the swerve happens for an isolated particle moving through the void, you know, without knowing of anything else — it just swerves. And this doesn’t happen. What we see happening in quantum mechanical uncertainty is always the result of an interaction. But because Epicurus just thought in terms of hard bodies, he just didn’t grasp this concept of fields and interactions, which we have, which can all explain this agglomeration of parts without needing the swerve. And correspondingly, there are still interpretations of quantum mechanics which do not interpret this uncertainty principle in a way that it defeats determinism. I don’t agree with those — so I’m rather more convinced by Heisenberg’s reasoning — that this uncertainty is there in principle from quantum mechanics. But this reasoning is not necessary — it’s an interpretation of the physics, it’s not what’s in the physics itself, necessarily.
Cassius: Yeah. I mean, on the sections where there are just areas where he had either mistakes or just insufficient information, the best thing we can do is get back to the conclusions that are currently supported by physics, that are also still consistent with the philosophy.
Martin: Yes, yeah.
Cassius: There’s so much in here that’s interesting to me personally. I just want to repeat, Martin — what you raised — I think you were commenting to some extent on Sedley’s article, but it’s kind of a new concept to me that I haven’t thought about a lot in the past: that you really do have an uncertainty aspect embedded in the classical physics as well. When you simply realize that the limit of your precision is the precision of your instrument at a particular time, you have to always keep in the back of your mind that to make a statement about what is going on that is more precise than your instruments allow is a very uncertain thing. You don’t really have to even think about whether something is swerving at a fixed time or a fixed place, or what Heisenberg was talking about, to realize that your ruler only has so many increments on it and below that space you’re not able to pontificate.
Martin: And Heisenberg — he explicitly wrote so — we don’t have the uncertainty only in quantum mechanics, it existed in the way we just discussed also already in classical physics.
Cassius: That’s not something I was familiar with — that’s very interesting.
Cassius: Well, I will try to reread the Sedley article between now and next week, because next week is going to be the discussion of the swerve and how it affects animals, living things, and the free will argument. We’ll take that up next week. Should we start talking about closing comments for today?
Elaine: I need to read more on physics. You know, yeah, and I read these things, but I admit that because it’s not part of my work or something, I just don’t think about it a lot. It’s not part of my everyday thinking. I just think it’s interesting.
Cassius: But I guess for our listeners that maybe you’re getting a little bit of eyes glazing over at this part of it — I don’t think it’s necessary to think about all this stuff constantly, but it’s probably worth your time to at least think through it once, and so maybe you can convince yourself, if there’s any unconvinced part of your brain, that things are happening naturally, the reality, the future is indeterminate — those things that you maybe just have to do once, and then you can probably forget about all the mechanics if you’ve completely convinced yourself.
Cassius: Yeah, the four of us have been raised in an environment where these issues we kind of accept that they’re resolved, that they’re not of day-to-day significance, and we don’t need to constantly be revisiting the issue of the mechanics of it. But depending on who you come into contact with, depending on who might be listening to the podcast — the whole issue of determinism and God’s guiding everything to happen because it works out well for mankind — those are arguments that have been very powerful in the history of the world and probably will not go away completely ever.
Martin: Yeah, yeah. Comment for me, for a closing comment — so this section exemplarily shows that even though a philosopher has got some basics of his physics wrong, he still managed to make it into a consistent physics supporting his philosophy, and with features which have strong analogies to modern physics as we know it now. So this is the one which I think is really stupendous.
Cassius: Right. Maybe my closing comment would be that I just know, over the years of my reading, that I’ve run into two particular articles that I would suggest that anybody interested in reading into this in more depth would be sure to read over before they moved on to another topic. That is the A.A. Long article on “Chance and Natural Law in Epicureanism,” and then an article I only read for the first time a couple of weeks ago — David Sedley’s “Epicurus’ Refutation of Determinism.” There’s so much out there written about the swerve — the Greenblatt book and so forth — that you can just get overwhelmed by the people who want to talk about the physics of it. But those two articles, in my experience, talk about the significance of the physics to the conclusions that Epicurus was drawing in terms of how the universe operates, and I think for most of us that’s where the rubber meets the road and what we’re really interested in.
Martin: Yeah, so for this one I would agree with the Sedley article, but for myself the Long article was too difficult — that one was really, really tough to get through. Even so, most people out there would probably also not really get through it.
Cassius: That’s why it is so valuable for us to have a panel of people talking, because Martin — my experience was almost — well, I wouldn’t say my experience was the opposite, but I haven’t read the Long article recently. And again, it sounds like maybe you have. But I remember reading the Long article and remembering points like the one I raised earlier, that Cicero did not make a certain argument, and so I found the Long article may have been easier for me than the Sedley article. But both of those guys — there are so many of these commentators out there who I think vary widely in terms of how sympathetic they are to Epicurus and how much effort they put into reconciling Epicurus to make sense. And Sedley and Long, at least in these articles — to my observation — both make a really good effort to put Epicurus’s views in perspective and make it all make sense. And I trust their conclusions much more than I trust some of the commentators. But this is such a deep subject that there’s — you could go on for days, years, talking about it.
Cassius: Even though Charles hasn’t had much to say today — right, Charles?
Charles: Yes, I’ve been here listening.
Cassius: Well, we’ll continue on to the free will aspect next week. Unless somebody has something else to add today.
Elaine: No, not for me.
Cassius: Okay, all right. Well, then thanks everybody. We’ll do it again in about a week.
Martin: All right, very good. Have a good week.
Charles: Okay, thanks. Bye-bye.