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Episode 242: Is Truth A Matter of Logic?

Transcript of Episode 242. Note: The following transcription was prepared with speech to text software, and has been only lightly edited for accuracy. This file has been prepared primarily as an aid in searching for material in the audio episode. This transcript likely contains errors, and should not be relied on for anything other than searching for discussions relevant to particular topics. Please consult the original audio episode for accurate information. If you come across egregious errors in the transcript below, please let us know in the Epicureanfriends.com forum!

Welcome to Episode 242 of Lucretius Today. This is a podcast dedicated to the poet Lucretius, who wrote On the Nature of Things, the most complete presentation of Epicurean philosophy left to us from the ancient world. Each week, we walk you through the Epicurean texts and discuss how Epicurean philosophy can apply to you today. If you find the Epicurean worldview attractive, we invite you to join us in the study of Epicurus at EpicureanFriends.com, where we have a thread to discuss this and each of our podcast episodes.

Today, we're continuing in Cicero's On the Nature of the Gods. We're now in the section where Cotta, the Academic Skeptic, is responding to Velleius's presentation of the Epicurean point of view. Last week, we spent most of the episode discussing the parallel between how Torquatus presented Epicurus's definition of the good as something which all philosophers agree is a standard by which we judge everything else, but we don't judge the standard itself by anything else, and Velleius's presentation of Epicurus's view of the gods as living beings that are blessed and imperishable. In both cases, we were setting forth what might be considered a definition, an explanation, or a pointer to a particular concept, so that we could then begin a detailed discussion.

As we go forward in section 34, Cotta is going to begin attacking Velleius's position, alleging that it is not true, and he's using the words 'true' and 'truth' in several different senses. We'll want to go back and examine what he's saying and what we should take away from any discussion of truth.

To set the stage for that briefly, a standard definition of truth that is often referenced when discussing truth philosophically is what's called the correspondence theory of truth. According to the Stanford Encyclopedia of Philosophy, the correspondence theory of truth is often traced back to Aristotle's well-known definition of truth in his Metaphysics, where he states: "To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true." Now, that’s classical Aristotelian wordplay, and while it makes sense when dissected, it ultimately comes down to a practical question of whether our statements and opinions correspond to what exists in reality. That’s where the word 'correspondence' comes in, as we're discussing truth in terms of describing, in words, something that corresponds with what is objectively real beyond us and beyond our words.

This article, which I'll link to in the show notes, explores different ways in which Plato and Aristotle approached this problem. This leads us into various discussions, such as Plato’s analogy of the cave, questioning whether one can ever see the truth or if we are merely observing reflections or shadows on a wall, and whether the senses are capable of apprehending truth. Plato argued that they are not, and that one must use logic to arrive at the truth. These are complex questions, but from a more practical point of view, we need to ensure that we have a working definition of 'truth' and 'true' or 'false,' which ends up being something like saying that our words paint a picture that corresponds with reality.

We also have references in Diogenes Laertius that are worth mentioning, which emphasize that Epicurus focused on words that describe reality, not on abstractions that have no relation to us. Diogenes Laertius records that Epicurus rejected logic as misleading, stating that the tests of truth are the sensations, preconceptions, and feelings. He quotes, "Nor is there anything which can refute the sensations." Here’s the important part for our discussion today: "Again, the fact of apperception confirms the truth of the sensation, and seeing and hearing are as much facts as feeling pain. From this, it follows that as regards the imperceptible, we must draw inferences from phenomena, those things that we are observing. For all thoughts have their origin in sensations by means of coincidence, analogy, similarity, and combination, reasoning too contributing something. The visions of the insane and those in dreams are true, for they cause movement, and that which does not exist cannot cause movement."

That last sentence, in particular, is often surprising, as it asserts that the visions of the insane and the things we see in dreams are true, which is a use of the word 'true' that is not commonly employed.

We're commonly using "true" to see that what you're talking about actually exists in objective reality—you can go out and touch it, and so forth. But what Epicurus is saying is that when you're asleep and have a dream, or when you're insane and have a vision, you are still perceiving things that are changing you, that are motivating you to do something. Whether you start awake because of the dream you're having, or if you're insane and think you're seeing something, you're reacting to something that's going on somewhere. In many cases, what's going on is something within your mind, but what Epicurus is focusing on is that you should consider those things to be true or real if they actually affect you. In Epicurus's analysis, anything that causes movement within you is something that exists as true or real, at least in that sense.

Continuing on in section 34, Diogenes Laertius records:

"Opinion they also call supposition and say that it [opinion] may be true or false. If it is confirmed or not contradicted, it is true. If it is not confirmed or is contradicted, it is false. For this reason, they introduced the notion of the 'problem,' a waiting confirmation—for example, waiting to come near the tower and see how it looks up close."

There’s also a long discussion of the same issue in Book Four of Lucretius, where he’s talking about the images (simulacra). But where we are in the text in section 34 is that Cotta is challenging Velleius’s position by saying, "You, Velleius, are committed to this idea of atoms being the basis of everything, but what I'm telling you is that atoms are absurd. Atoms were absurd when Democritus stated them; they were absurd when Leucippus stated them, and now you've brought down to our times this same absurdity that cannot be true." And Cotta says, "But where is truth? The truth cannot be in the atoms because whatever is made of atoms had to have a beginning, and if the gods are made of atoms, then they must have had a beginning, and that’s something absurd—that a god had a beginning."

Before I turn it over to Joshua, a comment: Cotta goes further and says, "What you're saying about the gods makes no sense, and in fact, it is a frequent practice among you, when you assert anything that has no resemblance to truth and wish to avoid reproach, to advance something else which is absolutely and utterly impossible in order that it may seem to your adversaries better to grant the point which had been a matter of doubt than to keep on continuously contradicting you on every point. Like Epicurus, when he found that if his atoms were to descend by their own weight, our actions could not be in our own power because their motions would be certain and necessary, he invented an expedient that escaped Democritus: to avoid necessity, he says that when the atoms descend by their own weight and gravity, they move a little obliquely. Surely, to make such an assertion as this is what one ought to be more ashamed of than acknowledging oneself unable to defend the proposition. His practice is the same against the logicians who say that in all propositions in which 'yes' or 'no' is required, one of them must be true. Epicurus was afraid that if this were granted in such a proposition as 'Epicurus will be alive or dead tomorrow,' either one or the other must necessarily be admitted. Therefore, he absolutely denied the necessity of 'yes' or 'no.' Can anything show stupidity in a greater degree? Zeno, being pressed by Arcesilaus, who pronounced all things to be false which were perceived by the senses, said that some things were false, but not all. Epicurus was afraid that if any one thing seen should be false, nothing could be true, and therefore he asserted all the senses to be infallible directors of truth. Nothing can be more rash than this, for by endeavoring to repel a light stroke, he receives a heavy blow."

We’ll stop there for now in the reading, but basically, what we're setting up for today's discussion is that Cotta is alleging that Epicurus is playing fast and loose with truth—that when he feels like he has run into an obstacle in one location, such as atoms falling downward leading to necessity (which he doesn't want), he just revises his understanding of the truth rather than providing an explanation that makes sense logically.

What we've basically done here in today's opening is set up this dilemma: Do we derive truth through logic and syllogistic reasoning, or do we derive truth through practical observation, through the senses? Which makes the most sense? Which best conforms to a practical definition of truth? Which version of truth is the most useful to us and, at the same time, the most correct?

I'm going to begin, Cassius, by drawing out that distinction you were making at the end of what you were saying, by highlighting the difference between two approaches to understanding things in nature. These two approaches are very much present in the ancient world; they were the subject of philosophical disputes in and before the time of Epicurus, and to some extent, these two positions still play a huge role in the arguments and debates we have today. So, the two modes of inquiry you might say, when you're looking into things in nature, are rationalism, of the kind typified by, let’s say, Plato, for example, and empiricism. We'll call Epicurus an empiricist. I know this isn’t strictly true necessarily, but for the purposes of comparison here, I think it's helpful.

The rationalist approach holds that people can gain knowledge of the truth through the application of reason and logic. I think of these Scholastic medieval monks, and so forth, writing books and coming up with a priori logical arguments for the existence of God.

It doesn't necessarily occur to them that if they want to understand some of this stuff, they should go examine things in nature, form hypotheses, and subject them to experiments. Instead, they start with a core set of axioms, use logic to develop their system, and never at any point do they take the conclusions they get from this process and subject them to experimentation. On the subject of the gods, this is not necessarily possible to subject to experiment.

The focus on geometry in the ancient world and Epicurus's impatience with the level of attention and study given to geometry is exemplified by the quote said to be over Plato's Academy: "Let no one ignorant of geometry enter here." This emphasis on geometry reflects an education in the rationalist style—starting with a set of axioms and definitions. If you can define what a point is, if you can define what a line is, with just a few basic axioms, you can build up this whole system. Of course, in geometry, which is a theoretical (versus practical) field, you can establish things with a very high level of certainty. But the question becomes: how do you apply that to the world we are actually living in?

Empiricism, on the other hand, very much focuses on the world we are actually living in because empiricism attempts to derive knowledge of the truth from experience, from sensation, from experimentation. So, we're not going to cloister ourselves in our studies and just work things out using mathematics, logic, or reason, starting not with observation but with basic assumptions. This approach, while it may be internally consistent, can lead you down a false path because the further you get from the ability to check your results in nature, the more in danger you are of going very wide of the mark. Whereas in empiricism, your approach is to constantly check your results by reference to things in nature.

So, in the case of geometry, for example, you did have Eratosthenes of Cyrene in the ancient world, who was a figure at the Library of Alexandria and a student of geometry. But he also had the question of how to use geometry, not just in this purely theoretical Euclidean space in our minds, but how to apply it in nature. He performed the well-known experiment to actually measure the circumference of the Earth using geometry, and the results were quite spectacular. But this kind of thing was quite rare among the Greeks, who just weren’t interested in the application of theory to the facts of nature.

To me, that’s the first place to start drawing this distinction between the rationalist approach and the empiricist approach. The other place to start is with Democritus. Democritus gets a mention here by Cotta, who, as you quoted, says:

"It is a frequent practice among you, when you assert anything that has no resemblance to truth and wish to avoid reproach, to advance something else which is absolutely and utterly impossible in order that it may seem to your adversaries better to grant you that point which has been a matter of doubt than to keep on pertinaciously contradicting you on every point. Like Epicurus, who, when he found that if his atoms were allowed to descend by their own weight, our actions could not be in our own power because their motions would be certain and necessary, invented an expedient which even escaped Democritus to avoid necessity."

The works of Democritus don’t survive except in very fragmentary form—we have a handful of quotations. If you go to the Wikiquote page on Democritus, there’s a section called The Source Book in Ancient Philosophy (1907), and under that, you have the fragments. Almost every single one of them deals with the question of truth. Democritus says, "Man should know from this that he has cut off from the truth. This argument too shows that in truth we know nothing about anything, but every man shares the generally prevailing opinion. And yet it will be obvious that it is difficult to really know of what sort each thing is." He also states, "Now that we do not really know of what sort each thing is or is not has often been shown." And then probably the most famous one that I’m familiar with, where he says, "Of truth we know nothing, for truth lies at the bottom of a well." Finally, there’s one that I’ve mentioned many times before: Democritus says, "By convention sweet, by convention bitter, by convention hot, by convention cold, by convention color, but in reality, there are only atoms and void. Only the atoms and the void exist; everything else is only thought to exist."

Democritus, far more than Epicurus, is prepared to take the kind of skeptical line that Cotta himself takes when he says, "Of truth we know nothing." Cotta would be very happy with that. There is ongoing debate in Epicurean circles as to how much of Epicurus’s philosophy was developed in service of his ethics. And Cotta puts his finger on the main point here, which is that Epicurus thought determinism was abhorrent. So how does he deal with this question of determinism? From Cotta's point of view, Epicurus just invents, ad hoc, a new law of nature to circumvent or evade this problem of determinism.

So, I think that really gives us an interesting test case. Let me jump in there for a second, Joshua, because that's a great example. Cotta and the determinists are accusing Epicurus of inventing something to explain what he wants the result to be, but Epicurus's response to that would be: "I'm not the one who's inventing something to explain nonsense. I'm the one who's looking at reality the way it is, and I see that I am not determined, and that means that something's going on with those atoms that allows me not to be determined. One possibility is that they swerve, and that ultimately translates into the ability of my mind to determine a particular path of its own."

But whatever the explanation is, I'm not going to lash myself to the mast of some logical position when it contradicts what I can see reality to be. I would use some analogies here. We often hear examples where people are following their cell phone navigation system when they're driving, especially at night or in bad weather. They’re following the navigation, and it says "turn here" because it thinks there's some bridge over some body of water, but the bridge, for some reason, is not there. Perhaps you'll be able to see that before you get to it and avoid falling into the river. But the bottom line is you do not follow a navigation system when you can see that ahead of you is a cliff that you're about to drive over.

If you're driving a Tesla today and you have automatic driving abilities, and it wants to swerve in a particular direction, and you see that there's a bulldozer in that direction, and for some reason, it's driving you straight into it, you'd better grab the wheel and override the automatic driving, or you're going to be dead. There are example after example of things like that you can analogize to reality. Reality is what you're ultimately concerned about; you're not ultimately concerned about consistency with some logical system that you believe is the truth.

There's a famous saying that people argue about whether Winston Churchill said it or John Maynard Keynes—apparently, Keynes is more likely the candidate—but it goes as part of a conversation where Keynes or Churchill, or whoever, says, "When the facts change, I change my opinion. What do you do, sir?" And that's the bottom line. You can come at something with a preconceived logical expectation, but when reality hits you in the face and it's not in accord with what you expect it to be logically, you go with reality. You don't go with some logical faith or belief that the logic is going to save you from the obvious hazard.

So, I think that's one of the ways that we can see where this is going because when Cotta accuses Epicurus of inventing an expedient, he's attempting to ridicule. He's attempting to say, "You don't know, Epicurus, what you're talking about with your swerve of the atoms; you're just inventing this, and that is absurd and ridiculous, something that not even a child should be willing to take a position on." But what Epicurus is saying in response to that is, "I'm taking that position because that's the reality of the situation, and that means that our logical framework needs to be adjusted. Reality isn't going to adjust itself—the bulldozer or the lake that's in front of our car is not going to adjust itself. We have to adjust for reality, not expect reality to adjust for us."

Yeah, I think it's an important part of this empiricist approach: you're not starting with first principles and building up a system. Instead, you are observing effects that exist in nature and trying to work your way back to the cause. There's an excellent quote on this from Charles Darwin. He's dealing with the problem of, "I've developed this theory of understanding speciation, how things came to be the way they are." He's looking at the effect, which is, "I went to the Galápagos, and I observed that some of the finches on this island have especially long beaks, and over here, they're different." But what happens when I apply this to a system that appears to be so complicated that my explanation may not even answer how this effect came to be produced?

And what Darwin says is this, speaking of the complication of the eye:

"To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection seems, I freely confess, absurd in the highest degree."

Now, if you're a young Earth creationist, that's where you stop the quote. And I see this quite a lot on the internet—that even Darwin admitted he was wrong here. But Darwin didn't stop there. He continues, and he says this:

"When it was first said that the sun stood still, and the world turned around, the common sense of mankind declared the doctrine false, but the old saying of vox populi, vox Dei, as every philosopher knows, cannot be trusted in science. Reason tells me"—

And again, it's not that he's reasoning from a set of axioms here. He's taking the effect and working his way back to the cause. He says:

"Reason tells me that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if, further, the eye ever varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory. How a nerve comes to be sensitive to light hardly concerns us more than how life itself originated. But I may remark that as some of the lowest organisms in which nerves cannot be detected are quite capable of perceiving light, it does not seem impossible that certain sensitive elements in their sarcode should become aggregated and developed into nerves endowed with the special sensibility."

Now, this passage contains its own problems, particularly when Charles Darwin says, "When it was first said that the sun stood still, and the world turned around, the common sense of mankind declared the doctrine false." Part of the process is that the accumulation of knowledge is gradual, and you can’t expect to develop it all at once. So what we know now is that not only would we not say that the sun stands still and the Earth orbits around it...

We would say that actually the Sun and the Earth are both in motion on their own terms. You could say of the Earth and the Moon, for example, that the Moon orbits around the Earth. That’s not exactly false, but maybe it’s more true to say that the Earth and the Moon both orbit around their common center of gravity, which is partway between the center of the Earth and the center of the Moon. What Albert Einstein discovered in nature is that there is no absolute frame of reference. If you hit a golf ball, from the point of view of the golf ball, the golf ball is sitting still and the world is moving away from it. And again, that’s not exactly a wrong way to put it.

So, when you get into celestial phenomena, as Epicurus does in the Letter to Pythocles, things become more tentative. But it doesn’t mean that we can’t gain knowledge about facts or that we can’t know what is true and what is not true. We still have this capacity, and this is actually very important for Epicurus—that some things can be known.

Yeah, I agree. It’s super important to Epicurus, and these things that we’re discussing today are particularly interesting to me because here we think we’re talking about On the Nature of the Gods, and some people are going to say, "Well, I don’t want to hear any discussion about religion." But what we’re dealing with in these questions is basic philosophy that applies to virtually anything we’re talking about—all the way through Darwin or any other way that we’re going to get at these basic philosophical issues.

Let’s go ahead and, in that context, tackle the second of Cotta’s challenges here. The first example that Cotta gave is that Epicurus said the atoms just fall straight down due to their weight, but then, when he didn’t like that result, he changed his position and said that they swerve a little bit. That’s one argument. Here’s a second argument that we also mention fairly regularly that has nothing to do with gods in particular, but it’s another example of logical consistency. Here’s the quote again:

"Epicurus’s practice is the same against the logicians who say that in all propositions in which yes or no is required, one of them must be true. He was afraid that if this were granted in such a proposition as 'Epicurus will be alive or dead tomorrow,' either one or the other must necessarily be admitted. Therefore, he absolutely denied the necessity of yes or no. How can anything show stupidity in a greater degree?"

Okay, so in this example, we may even have a clearer setup for where Epicurus is going and how to make sense of it. It’s tempting to read something like that and sort of take a superficial view that, "Well, this person is making a very common-sense suggestion: either you’re going to be alive tomorrow, or you’re not. Now, why in the world would a common-sense philosopher like Epicurus refuse to admit that one of those things is going to be true?" And again, people accuse Epicurus of being a muddled or superficial thinker, but I think this is a great example of the depth of his thought because he’s pointing out to us that there are other issues involved rather than just agreeing to this proposition.

The issue that Epicurus is always wanting us to keep in mind is what we’ve been discussing: that logic is not the ultimate arbiter of reality. Those who suggest that you can set reality into a syllogism and that the fact of setting something into a syllogism like, "Epicurus or Metrodorus or Hermarchus or any person is either going to be alive or dead tomorrow," and that one of the two of them must necessarily be true—well, it’s very tempting for us to think that this construction of words has created something that, in reality, must necessarily be true. But no construction of words is necessarily going to control and command reality. It’s reality that controls and commands reality.

It is reality that we can attempt to predict the future using words, that we can do our best to describe and use our experience to predict the future. But because there is no fate and because there is no necessity, we cannot be certain that a prediction about the future is either true or false. In adding that caveat, I believe Martin has explained to us in the past that it’s that aspect of this—the prediction of the future—that is the real issue. Obviously, we do believe that it is possible to say that certain things are true and certain things are false, and that’s the whole error with skepticism in the first place. But the attempt to predict the future is something different than making a factual statement about the present.

The future has all sorts of factors that will come into play to bring about the future. And while we can do a really good job of predicting things, the ability to predict every eventuality and to say that, by necessity, something is going to happen is a step too far. Epicurus points that out to us by saying that it’s not even legitimate to ask or answer such a question. As Cotta says, "Therefore, he absolutely denied the necessity of yes or no." Well, that’s not to say that Epicurus doesn’t have the ability to make a pretty good prediction. Just like we can. If Hermarchus is 30 years old and in peak physical condition, you can make a pretty strong prediction that he’s going to be alive tomorrow—unless he’s in the middle of a war, or unless he’s taking up some dangerous occupation that would put his life in jeopardy.

But it's not the same thing to predict the future based on your rational observation of the past as it is to say that Hermarchus necessarily must be alive tomorrow. Epicurus always goes to great lengths to point out oversteps, overstatements, and overclaims by logic—as if logic has the ability to compel reality, which it does not. So, you’re dealing with this kind of on face value, which is taking the question to task on its own terms.

DeWitt, in his book Epicurus and His Philosophy, puts it this way:

"A fourth kind of necessity was dialectical. This was simply ignored. For example, when the disjunctive proposition 'Tomorrow Hermarchus will either be alive or dead' was put up to Epicurus, he declined to give an answer. He was too wary a dialectician himself to swallow a dialectical bait."

Let me give an example of how this works. We have discussed a little bit the ontological argument for the existence of God from St. Anselm. I’m going to give you a syllogism—it’s a syllogism that even Bertrand Russell himself struggled with. There’s a famous story where he went to buy a pouch of tobacco, and while he was walking down the street, he threw it up in the air and said, "The ontological argument is valid! The ontological argument is valid!" And then later on, he said it’s easier to feel that it’s false than to demonstrate why it’s false. This is the problem with a priori reasoning—with reasoning without reference to facts in nature and without the ability to test the conclusions in nature.

So, in the third chapter of a text called Proslogion by Anselm, the argument is laid out this way:

  1. By definition, God is a being than which none greater can be imagined.
  2. A being that necessarily exists in reality is greater than a being that does not necessarily exist.
  3. Thus, by definition, if God exists as an idea in the mind but does not necessarily exist in reality, then we can imagine something that is greater than God.
  4. But we cannot imagine something that is greater than God.
  5. Thus, if God exists in the mind as an idea, then God necessarily exists in reality.
  6. God exists in the mind as an idea.
  7. Therefore, God necessarily exists in reality.

If you accept the earlier premises, you’re forced to accept the conclusion: God exists in reality. The problem is, it’s very easy to establish a syllogism using even some of Anselm’s own premises and arrive at a very different conclusion. Let me see if I can do this in the moment here—it’s somewhat difficult, but I’ll try.

I’ll accept the first three of his premises:

  1. By definition, God is a being than which none greater can be imagined.
  2. A being that necessarily exists in reality is greater than a being that does not necessarily exist in reality.
  3. Thus, by definition, if God exists as an idea in the mind but does not necessarily exist in reality, then we can imagine something that is greater than God.

Now, I’ll add my own premise, which I think is true, and arrive at a different conclusion:

  • However, a being that has the power to choose whether or not to exist in reality at any given moment is greater than a being that only necessarily exists in reality, because a being that is not bound by necessity is greater than a being that is bound by necessity.

Thus:

  • God can choose at any given moment whether or not to exist in reality. However, it’s not possible for humans to know in any given moment whether God has chosen to exist in reality or chosen not to exist in reality. Since we cannot know whether God has chosen to exist or chosen not to exist, it is not possible to know whether God exists in reality.

I’m using some of his own premises here and the same kind of a priori logical argument that St. Anselm is using, but instead of arriving at the conclusion that God necessarily exists in reality, I’m arriving at the conclusion that it’s not possible to know whether God exists in reality—two very contradictory conclusions arrived at by the same method of reasoning.

So, what do we learn from this? Do we learn that one conclusion is true and the other is not necessarily true? Or do we conclude from this that the very project of trying to prove the existence of a being in nature using an a priori logical syllogism is insufficient to demonstrate the actual existence of an actual being in nature? That’s the approach I take, and that’s also the approach that David Hume takes in response. David Hume, in his book Dialogues Concerning Natural Religion, proposed that nothing can be proven to exist using only a priori reasoning. He says:

"There is an evident absurdity in pretending to demonstrate a matter of fact or to prove it by any arguments a priori. Nothing is demonstrable unless the contrary implies a contradiction."

We’re dealing with the same problem here in the text from Cotta—nothing that is distinctly conceivable implies a contradiction.

Whatever we conceive as existent, we can also conceive as non-existent. There is no being, therefore, whose non-existence implies a contradiction. Consequently, there is no being whose existence is demonstrable. It’s this flaw that lies at the heart of all of these arguments that use a priori reasoning to demonstrate the existence of God. You cannot logic a thing into existence, in other words, is the conclusion here.

So, when you’re dealing with a challenge like the one Cotta presents to Epicurus, sometimes the best thing to do is to say, "What I’m looking for is not this approach. What I’m looking for is evidence that you can point to in nature that suggests the conclusion you’re trying to reach using logic is true." If you can demonstrate this to be the case, then implicitly your conclusion will be so much stronger than any conclusion reached using only a priori logic could ever be.

I think there are different ways you can tackle the challenge here, but the approach to say, "Stop, no, I’m not going to go down this path," is like if any one of Socrates’s interlocutors had just said, "We’re not doing this dialectic game. Just point to something in nature that we can talk about. I don’t want to get lost in the weeds of your logical miasma where nobody really seems to understand anything, and we all just get confused." This is a bit complicated, so I will link to a thread from an earlier episode where I discussed this at more length in one of my posts. That would be a good place, I think, to examine some of the problems that lie at the heart of this rigorously logical approach, which does not even attempt to test itself by reference to the effects that exist in nature.

I thought that was a great explanation, and your summary at the end was very good as well. I look forward to that link. I know there are people out there who, as soon as they hear the words a priori, their eyes glaze over, and their minds close shut. For much of my life, I would consider myself in that category. But as important as it is to get down in the weeds and deal with the argument, it’s also important to be able to surface above the water and be able to state this kind of problem in very clear terms that hopefully anyone can understand. Because it’s continuously this relationship issue between words and logic versus reality that people need to understand: reality, nature takes priority in the end.

Whenever there’s a conflict between what we perceive, what nature tells us, and what our logic and our words would tell us in a different direction, you’ve got to go with nature—you’ve got to go with reality. That’s where Epicurus is going by talking about how even the visions of the insane and those things we see in dreams have a certain degree of truth to them because those things that affect us are, in fact, real to us.

One of the Epicurean texts I’d point to on this issue, which we’ve had some debates about regarding what it means, is a sentence that Bailey translated in section 34 of Diogenes Laertius. For purposes of this discussion, I’ll go with the way Bailey has translated it and presume that Bailey has translated it correctly because I think this sentence makes the point that you’ve just been discussing. Diogenes Laertius says that Epicurus held:

"Of investigations, some concern actual things and others mere words."

I would suggest that one way of getting a handle on this issue is to realize that actual things in reality are more important to us than mere words. When we run into an inconsistency, a conflict, or a nonsensical combination of words, we adjust our words to fit reality. We do not expect reality to adjust itself to fit our words.

Before we bring today’s discussion to an end, there is one more argument in this chain that Cotta brings up that we should include before we move on next week into section 26. Cotta also says:

"Zeno, being pressed by Arcesilaus, who pronounced all things to be false which are perceived by the senses, said that some things were false but not all. Now Cotta is holding that up as the right position."

Cotta then says:

"Epicurus was afraid that if any one thing seen should be false, nothing could be true, and therefore he asserted all the senses to be infallible directors of truth. And he says nothing can be more rash than this, for by endeavoring to repel a light stroke, he receives a heavy blow."

Cotta is suggesting that Epicurus has taken an absurd position by saying that all the senses are true because he refuses to admit that sometimes they are true and sometimes they are false. Of course, that is not the correct interpretation of Epicurus’s position because Epicurus says that truth and falsehood reside in the mind—truth and falsehood are matters of opinion. It is not the senses and the perceptions that are true or false; it is the construction that we give to them when we process them in our minds.

Cotta is attempting to hold Epicurus up to ridicule on this point, but it really is one of the strongest positions that Epicurus takes. It’s not the senses that are right or wrong—it’s our opinions about what the senses tell us that can sometimes be wrong. So, Cotta is once again off on the wrong track, and Epicurus’s position is the one that makes the most sense.

On the Wikipedia page, it says:

"In Athens, Arcesilaus interacted with the Pyrrhonist philosopher Timon of Phlius, whose philosophy appears to have influenced Arcesilaus to become the first Academic to adopt a position of philosophical skepticism—that is, he doubted the ability of the senses to discover truth about the world, although he may have continued to believe in the existence of truth itself."

This brought in the skeptical phase of the Academy. His chief opponent was his contemporary, Zeno of Citium, the founder of Stoicism, whose dogma of katalepsis—that is, that reality could be comprehended with certainty—Arcesilaus denied. So, Cotta seems to be saying that while Arcesilaus’s position—that certainty in knowledge is impossible—is the best position, Cotta also thinks that Zeno’s position, which holds that some things perceived by the senses are false but not all things, is a better position than Epicurus’s. According to Cotta, Epicurus goes "hog wild" in saying that everything reported by the senses is true, that the senses are infallible directors of truth.

This is an issue we’ve talked about quite a lot, and one of the ways you’ve spoken about this in the past, Cassius, is that the senses report things without opinion or bias. It’s not to say that in our minds, when reasoning on what we’ve received through the senses, we don’t arrive at false opinions—we certainly often do arrive at false opinions about the senses—but the senses don’t lie in the sense that they don’t add their own bias or filter to the input that’s coming in.

Kalosyni: You’ve been presenting Epicurus’s ideas regarding how the senses are true, and at the same time, I keep thinking about modern psychology and how we understand the human brain. It’s a little hard to really accept that all the senses are absolutely true. We can think that the senses are most of the time correct and that occasionally there’s some kind of error that occurs, but it’s very rare. That makes more sense to me than saying that they’re always true.

With modern psychology, there’s research where they have studied what happens when people are perceiving things and when things go wrong. So, from a modern understanding, we could start to see patterns because you can’t really separate the eye’s perception from what’s being registered—it’s just like they’re bound together. So, it’s just really hard for me to hear that the senses are always true.

Cassius: Yeah, you’re stating the same false premise that the ancients were stating in a modern way, as if the modern world has somehow revised the way the senses operate. Epicurus’s point was hard for the ancients to understand, and it’s hard for the modern ear to understand because the word "true" has multiple meanings, has multiple senses to it. Epicurus’s point then and his point today is the same: the eyes do not tell us anything about what they are seeing; they provide data to us about the brightness of a thing, the color of a thing, but they don’t tell us what it is they are seeing. So, it is always improper to say that the eyes are right or wrong. The eyes are never right or wrong; the eyes are relaying whatever they can.

They may be astigmatic, they may be nearsighted, they may be farsighted, you may be looking through a rainstorm, you may be looking through a fog, you may be looking at night—there are innumerable ways in which what it is your mind is trying to grasp is being blocked by obstacles between you and that other thing. But when your mind is incapable of forming a true conclusion that does correspond with reality, it’s not the fault of the eyes for telling you something wrong. All the eyes can ever do is provide to you what they are wired to provide, and it is your mind that has to make the decision about what it is the eyes are presenting and turn that data into an opinion.

That is Epicurus’s point: opinions are true or false, but the eyes, the ears, the nose—they are never false or true. I’m glad you said it the way you did—it’s not just modern versus ancient; it’s the issues of the multiple definitions of words like "true." You immediately jump to the conclusion that the word "true" means that your opinion corresponds with reality, but that’s not what the eyes are doing.

It’s the same situation with gods. People are so wired to presume that gods are omnipotent, omniscient, and have all these supernatural powers that they cannot separate in their minds the meaning of the word "god" from their preconceived notions. But, like it or not, that’s what Epicurus is telling us: if we don’t separate these things out, we will never figure out what is really true in the world. If we allow preconceived definitions of words like "gods" or "true" to get in the way of us perceiving the reality of things, then we’re going to live unhappy lives. We’re never going to get nature figured out because nature doesn’t take orders from us. Nature doesn’t let us dictate in words the way nature really is. Words are helpful, words can be important, but they can also be obstacles. If we don’t take command of the words and look to nature for our definition of the words—if we think we’re going to define words the way we want to, come hell or high water—then we are going to have hell and high water, just like the analogy of listening to your Google navigator when you’re driving off a cliff. The cliff is going to kill you regardless of what your Google navigator or logical system would lead you to believe.

That’s been the theme of what we, as attempting to defend Epicurus’s position, need to be able to unwind. There’s one more point here before we close today. In the same argument, Cotta is accusing Velleius of the same thing in regards to the gods.

Cotta is saying that on the subject of the nature of the gods, Epicurus falls into the same error because, in order to avoid the concretion of individual bodies lest death and dissolution should be the consequence—because, of course, Epicurus has been holding that if a body comes together from atoms, it’s eventually going to split apart—Cotta attacks him on that point. Cotta says, "Well, Epicurus knows that death and dissolution occur if you have a body, so therefore he denies that the gods have a body but instead says they have something like a body and that they don't have blood but have something like blood." Cotta is saying that’s where this quasi stuff is coming from—that Epicurus doesn’t know the right answer and is just submitting something that’s nonsensical.

The proper response to that is what Lucretius says in De Rerum Natura, Book Four, around line 500, which I had up to help conclude today’s episode. In line 500, Lucretius says—this is Bailey’s translation:

"And if reason is unable to unravel the cause why those things which close at hand are seen square are seen round from a distance, still it is better, through lack of reasoning, to be at fault in accounting for the cause of either shape rather than to let things clearly seen slip abroad from your grasp and to assail the grounds of belief and to pluck up the whole foundation on which life and existence rest. For not only would all reasoning fall away, but life too itself would collapse straightway unless you choose to trust the senses and avoid those headlong spots and all other things of this kind which must be shunned and make for what is opposite to these. Know then that all is but an empty store of words which has been drawn up and arrayed against the senses."

I’m going to maintain that the point of that is clear. For example, when you see a tower at a distance and it appears to be round even though up close it is square, in that situation or in many of the situations we’re talking about today, you’re faced with an apparent contradiction. You don’t know what the real explanation is—up close it looks square, from a distance it looks round. Are your eyes wrong when you’re a mile away and the tower looks round? You have many issues like that where your senses appear to be leading you in a direction that you think is wrong.

Well, you have to make a decision. If you don’t understand optics, if you don’t understand why things look different from a distance versus when you’re up close, what are you going to do? Are you going to say, "Well, I can’t trust my eyes; I’m just going to stop trusting my eyes. I’m going to say these things are unreliable, the eyes need to be discarded, I’m going to close them, I’m going to gouge them out." And of course, if you do that, you’re going to die, and you deserve to die if you’re not able to figure out that what’s important to you in life is the reality you’re dealing with, not some logical position that "the eyes had always better be right all the time, or else I’m going to pluck them out."

Well, your eyes are never right or wrong. Your eyes are your eyes, and you have to understand the nature of things and how your eyes work and be able to predict whether the distance is a problem, whether fog or other distortions are a problem, and realize that it’s not something that you have to despair over and throw away your eyes. You can reason through the facts and allow yourself to make accurate predictions no matter the circumstances you’re under.

Epicurus is constantly asserting the primacy of nature, the primacy of the senses, and in this book, Lucretius is really hammering this point home. If you give up your confidence in your senses and your understanding of how they operate, and if you say, "Well, I better go looking for something else besides the senses," that’s when you’re going to go straight headlong into Plato and his ideal forms, or Aristotle and his essences, or religion and their divine revelation. You’re going to pick something which is really a fantasy, something made up in your mind that does not really exist, versus trusting the faculties that nature has given you to live according to nature.

So many of these questions come down to this kind of choice that has to be made. Epicurus can’t explain to you how it is that the atoms can swerve at no fixed time and no fixed place, and Epicurus can’t tell you as much as you might like to know what type of body exactly the gods have. But he’s going to tell you that when you have reality thrusting itself in your face, you deal with reality. You don’t give up confidence in your senses or your natural faculties; you do the best you can, and you move forward with living happily rather than abandoning nature and guaranteeing a bad result.

Let’s go ahead and bring today’s episode to a close with some closing thoughts. Joshua, I really think that developing this distinction between this hyper-logical, Platonist approach and comparing that to a more empiricist approach, as we see in Epicurus, really highlights one of the fault lines between these ancient thinkers. When Cotta says, in response to Epicurus declining to take him up on dialectic, "Can anything show stupidity in a greater degree than to decline pure logic as the way to understand human life and nature and the cosmos?" I guess one response would be, "Can anything show stupidity in a greater degree, Cotta, than to assume that the conclusions of your pure logic are true even though you’ve never tested those conclusions in nature?"

This is the paradigm shift here between the two positions, and that conflict has not stopped. We’re still dealing with the fallout from this approach. One last thing, Cassius, because we’ve been talking about the atom swerving at no particular place or time by just a small amount—there’s an article that you often cite on this question, and it bears on this discussion of truth.

Cassius: Yes, Joshua, you’re talking about David Sedley’s article on Epicurus's Refutation of Determinism, and it’s very interesting how the same argument applies both to determinism and to skepticism. That brings us back to this issue of truth because in that article, David Sedley observes—in fact, he takes the position that he doesn’t think Epicurus’s theory of the swerve was something that Epicurus came up with through physics. He thinks that, yes, Epicurus adopted it and incorporated it into his physics and made the observation that, "Well, it’s impossible to be able to see that this very slight swerve does not occur," but Sedley takes the position that Epicurus really came up with the swerve as a result of what we’re talking about today—this conflict between logical necessity versus the reality of the way things really are. That’s where Epicurus made his choice to go with reality—he’s making his choice to stop his car at the edge of the cliff and not go over, no matter what the navigation says about a bridge being there. He’s going with reality, always.

So, it’s Epicurus’s refutation of determinism that there are two levels of truth. There’s the atomic level—to say that the atom and the void exist is certainly true—but it’s also true to say that the atoms come together through the void and form bodies and that these bodies have properties and qualities that are real and true to us. Neither perspective—neither the atomic perspective nor our perspective—has a monopoly on the truth. Both of them are true and real in their own paradigms, and just because Democritus says in the end that there’s nothing but atoms and void, that is not a reason for you to fall into despair and nihilism and think, "Oh my gosh, I’m nothing but a bunch of dirt flying through the void, so let’s go ahead and kill ourselves because nothing really matters anyway," like in the Queen song. So again, yes, that is an excellent article. I’ll link it in the show notes today as well: Epicurus’s Refutation of Determinism by one of the real luminaries of Epicurean scholarship, David Sedley.

Joshua: I think that’s a great way to end here by tying it back into Democritus with his claim that, "Of truth we know nothing because truth lies at the bottom of the well," and that the only thing that really exists is the atoms and the void through which they flow, so things that seem to exist on our level of experience aren’t real or aren’t true. That, to me, is a very corrosive approach to philosophy and human life. So I think that’s very good. It also ties in with Einstein and his view that there are no absolute frames of reference—in other words, that something can be true from two different perspectives or two different levels of experience. I remember Richard Dawkins was trying to develop a view of what he called "middle world," which is nature through the experience of humans and other creatures on our level of existence, right? You know, for insects, forces like gravity are less important, but forces like surface tension are much more important than they are for us. You have these insects that can walk on water—well, we can’t do that because of our mass. But if you’re small enough, if you exist at that level of reality, your experience of nature is very, very different from our experience of nature. But it doesn’t mean that one of these is false and the other one is true—you have different levels at which experience can be had, and the experience is true at both levels. It’s an interesting thing to think about, but it also applies to everything we’re talking about.

Cassius: Yes, Joshua, you used the word "corrosive," and that’s where we’ll close today. That’s why all of this is so fundamentally important, and people will use analogies to the Pontius Pilate question in the Bible about "What is truth?" I really think Pontius Pilate deserves a lot of credit—that question is the ultimate question, and it’s where these people are going wrong in their analysis by thinking that they have a monopoly on the word "truth" and that their explanation, their word game, is what’s really true. And if you’re not consistent with their word game, then you’re false and you’re wrong. That’s where Epicurus is telling us to get to the real meaning of the word "true": realize that it’s actual things that we’re concerned about, not simply words, and to go forward and live happily according to nature and according to the reality of nature, not according to our imperfect methods of attempting to constrict nature into a certain set of words that conform to our opinion of the way we think things should be.

Okay, let’s close on that for today. Thanks for your time. Be sure to drop by the forum—we’ll have links to the references we’ve made today. We will come back next week on section 26 of book one of On the Nature of the Gods. See you then. Bye.