Episode 054 - Reason Is Dependent on the Senses
Date: 01/17/21
Link: https://www.epicureanfriends.com/thread/1837-episode-fifty-four-reason-is-dependent-on-the-senses/
Summary
Section titled “Summary”Book Four’s passage on how reason is wholly dependent on the senses is read and discussed. The text argues that total skepticism is self-defeating; that knowledge of truth is originally derived from the senses; that no faculty can override the senses without claiming greater certainty; and that each sense has a separate province, with the building analogy closing the section.
The discussion ranges widely: certainty as a brain sensation (Robert A. Burton’s On Being Certain); faith versus empirical observation; Elaine’s note that Lucretius’s claim about strictly separate senses is not quite neurobiologically correct (synesthesia, smell/taste and COVID, bone-vibration from sound); and an extended debate on whether “logic” and “reason” mean the same thing, with Martin arguing logic is independent of empirical reality while Cassius defends a Mr. Spock-inflected sense of logic as data-driven.
Transcript
Section titled “Transcript”Cassius: Welcome to Episode 54 of Lucretius Today. I am 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. For anyone who is not familiar with our podcast, please check back to Episode 1 for a discussion of our goals and our ground rules. If you have any questions about that, please be sure to contact us at EpicureanFriends.com for more information. In today’s podcast, we discuss one of the most important sections of the entire poem — the section in Book 4 that discusses how reason is dependent upon the senses. Let’s join today’s discussion with Charles reading the text.
Charles: Lastly, if anyone thinks that he knows nothing, he cannot be sure that he knows this. When he confesses that he knows nothing at all, I shall avoid disputing with such a trifler who perverts all things, and like a tumbler with his head prone to the earth, can go no otherwise than backwards. And yet, allow that he knows this, I would ask, since he had nothing before to lead him into such a knowledge, whence he had the notion what it was to know or not to know, what it was that gave him an idea of truth or falsehood, and what taught him to distinguish between doubt and certainty. But you will find that knowledge of truth is originally derived from the senses, nor can the senses be contradicted, for whatever is able by the evidence of an opposite truth to convince the senses of falsehood must be something of greater certainty than they. But what can deserve greater credit than the senses — that reason derived from erring sense, claim the privilege to contradict it? Reason that depends wholly upon the senses — which unless you allow to be true, all reason must be false. Can the ears correct the eyes, or the touch the ears, or will taste confute the touch, or shall the nose or eyes convince the rest? This I think cannot be, for every sense has a separate faculty of its own. Each has its distinct powers, and therefore an object soft or hard, hot or cold, must necessarily be distinguished as soft or hard, hot or cold, by one sense separately — that is, the touch. It is the sole province of another, the sight, to perceive the colors of things and the several properties that belong to them. The taste has its distinct office; odors particularly affect the smell and sound the ears; and therefore it cannot be that one sense should correct another, nor can the same sense correct itself, since an equal credit ought to be given to each. And therefore whatever the senses at any time discover to us must be certain, and though reason is not able to assign a cause why an object that is really four-square, when near, should appear round when seen at a distance, yet if we cannot explain this difficulty, it is better to give any solution, even a false one, than to deliver up all certainty out of our power, to break in upon our first principle of belief, and tear up all foundations upon which our life and security depend. For not only all reason must be overthrown, but life itself must be immediately extinguished, unless you give credit to your senses. These direct you to fly from a precipice and other evils of this sort which are to be avoided, and to pursue what tends to your security. All therefore is nothing more than an empty parade of words that can be offered against a certainty of sense. Lastly, as in a building, if the principal rule of the artificer be not true, if his line be not exact, or his level bear but the least to either side, everything must needs be wrong and crooked. The whole fabric must be ill-shaped, declining, hanging over, leaning, and irregular, so that some parts will seem ready to fall and tumble down, because the whole was at first disordered by false principles. So the reason of things must of necessity be wrong and false, which is founded upon a false representation of the senses.
Cassius: Charles, thank you for reading that today. This is one of the most important passages I think we’ve attacked anywhere in the book, as a matter of fact. It’s certainly one of the clearest on epistemological issues and conclusions that Epicurus drew, and a lot of the conversations that we have on the different forums that we participate in end up being related to the subjects discussed here. So I don’t know if we’ll be able to tackle it all today, but we will get started at the beginning of this passage. Let me repeat the first part so we know what we’re talking about: “If anyone thinks he knows nothing, he cannot be sure he knows this when he confesses that he knows nothing at all.” Now what would someone like to say about that?
Martin: Well, I talked to my co-worker about that last year and he said that was nothing but a word game.
Cassius: A word game — because who believed in it? Your co-worker or Epicurus?
Martin: My co-worker.
Cassius: Well, is it a word game? That’s what we should probably discuss. Elaine, is it a word game?
Elaine: It is a little bit, because it’s confusing. It’s like when people accuse certain types of atheists of having a religion. If a person like me — I’m an atheist, I’m just without gods, I’m lacking that sensation of belief in anything supernatural — the absence of a sense of knowledge is not the same as knowledge about something. It’s a different experience. When you believe something is not true, for me it’s a sensation — a feeling of knowing that something is wrong. And if there’s just an absence of that belief, that is a different internal sensation. So if a skeptic says “I don’t have the sensation of knowing anything, I don’t have a feeling of certainty about anything,” then they’d agree that when you say “how can you be certain that you don’t know anything?” — well, they’d say “I just don’t have that feeling, I can report on that.” So it’s not self-contradictory; they’re just reporting an absence of a sensation.
Cassius: I think somebody trying to defend the statement as written might say that what he’s observing is that the statement of the skeptic is self-refuting or self-contradictory.
Elaine: I know, but it’s not. They’re reporting that they have no sensation of certainty about anything. That’s a report of experience. But there’s been some interesting research — there’s a book about certainty or knowing. There’s a certain sensation people can have when they feel like they know something, and we usually associate it with content, but there’s actually research where they can stimulate part of the brain and give people the experience that they know something but without any content. They say “I know — I just feel certain — but about what I don’t know.” So there’s a brain function that people are describing when they talk about this, and they’re not aware that there’s actually a specific brain function doing that.
Cassius: I was concerned we might not finish this series of passages today — we may not finish the first sentence the way we’re going. So let’s turn to Martin. Is this sentence a valid and persuasive logical attack on skepticism, or is it a word game?
Martin: If you interpret it, it’s perfectly fine, but we can also take it from the perspective that it’s just a logic game. That means we play around with statements where we assume that one statement is knowable to be absolutely true or false, and then logic gives immediately the result. From that angle it’s just a word game. But if we interpret it as actually expressing a sensation, then it’s not a word game — then we’re talking about something that can be determined experimentally.
Elaine: I know some people that are skeptics who would totally agree: “Yep, you’re right, I can’t be sure that I don’t know anything.” It wouldn’t be a problem to them. It would totally fit their skepticism rather than being an argument against it. They would say, “I just don’t feel like we can know anything, and when you say ‘how can you know that you don’t know anything?’ — yep, you’ve got a point, I don’t know that either.” It’s not contradictory.
Cassius: So Elaine, you do not consider that position to be trifling — “like a tumbler with his head prone to the earth.”
Elaine: No. I think it’s just a person who constitutionally is more concerned by that tiny percentage of uncertainty. Some people will pay more attention to the foreground and some to the background, and people who are constitutionally skeptics zone in on that teeny tiny bit of uncertainty and can’t think about anything else. This argument makes sense to Epicurus and Lucretius, but it would not dissuade a skeptic because a skeptic would say “yeah, you’re right, can’t be certain about that either.” You must have met one rude skeptic!
Cassius: I live in Rocket City, USA — we have one of the highest concentrations of PhDs anywhere — and they wouldn’t have any problem saying “yeah, you’re right, I could be a brain in a vat, I can’t know.” And they get real obsessed with that sometimes. Maybe that’s where I’m learning the most in these discussions: there are certain people who just look at things differently, and they’re not going to come around to my point of view in the end, and I’m not going to theirs. There’s evidence from psychology that you actually entrench a person’s position when you try to persuade them out of it with logic.
Elaine: Exactly. And it does have the effect of preaching to the choir — your side will be like “yeah, that’s logical, why don’t they believe that?” but it doesn’t convince people with the contrary opinion. Though it does build your team.
Cassius: I think Epicurus is doing both — dealing with the logical argument and grounding it in experience. But I want to point out the last phrase: “what taught him to distinguish between doubt and certainty?” A full-going skeptic doesn’t distinguish — life is just an experience of doubt. But for the rest of us, what is it that distinguishes? And current neurology research is showing us that there’s actually a brain function that gives you that sense of knowing — and that is fascinating. Let me repeat the next sentence: “Since he had nothing before to lead him into such a knowledge, whence had he the notion what it was to know or not to know, what gave him an idea of truth or falsehood, and what taught him to distinguish between doubt and certainty?” Before we move to the role of the senses, we ought to discuss the context — he seems to be presuming that there is a difference between truth and falsehood.
Elaine: Some people — skeptics — can at least point to their childhood, when they had a sensation of knowing, and then as they thought about things more, got so focused on uncertainty that they don’t really experience certainty anymore. But they can remember the sensation and can recognize it when other people describe it. You’re equating knowledge with the sensation.
Cassius: Let’s talk about that. Martin, is knowledge a feeling?
Martin: We certainly have a feeling of whether we are sure about knowing something. For example, if you look at mathematics, which is built entirely on logic, I consider a proved theorem as absolute truth to know, and something to the opposite is an absolute fault. When people did not yet separate this clearly from what is empirically known, it leads to confusion, because whatever is empirically known does not have this certainty of logic. We have the chance that things are completely different than we think. With trivial things it’s unlikely, but with non-trivial things it may happen. And the feeling of whether we know something or not doesn’t make this distinction. If I go through a mathematical proof and think it’s correct, I have the feeling “yes, I know this now” — and I know even that it’s an absolute truth, but also that it’s completely irrelevant for reality. Things about reality come in from the senses and are open to interpretation.
Cassius: What is it that gives you the idea that there is something such as truth or falsehood? Is it a feeling?
Martin: For a specific topic, knowing that I have certainty — that is an inner feeling.
Elaine: I found the book — the title is On Being Certain: Believing You’re Right Even When You’re Not by Robert A. Burton, M.D. It has a summary of the neuroscience research into this sensation. A lot of people will call it a feeling — it can be a pleasurable feeling, this feeling of epiphany, of knowing. I think it’s a brain function and I’m basing that on observations of reality. It’s different from the way Epicurus is presenting it here, but I don’t think that would be a problem for him to incorporate if he were presented with the research.
Cassius: Charles, you haven’t said too much yet. What do you think?
Charles: Kind of agreeing with Elaine — on the book she brought up and also how it’s not so different that it couldn’t be incorporated. Just about the feeling and observations of other people and how they can begin to feel certainty.
Cassius: Okay. Let me be Pontius Pilate and ask: what is truth? Let me read you an excerpt from this book: “Despite how certainty feels, it is neither a conscious choice nor even a thought process. Certainty and similar states of knowing what we know arise out of involuntary brain mechanisms that, like love or anger, function independently of reason.” Independently of reason. Now I do think some people get a sensation of certainty from logic, and that can lead them in all kinds of crazy directions. My sense of sufficient certainty — not absolute certainty — comes from looking at a lot of evidence and sense data.
Elaine: When I hear you describing this, Cassius, I hear you defining knowing something as having a sensation of certainty about something.
Cassius: Yes, that’s right. Does everybody agree that’s what we mean when we say we know something?
Elaine: That’s what the evidence clearly says — it’s not vague. If you’re a person that goes with observations as providing truth, this is not something you can ignore. The neuroscience research is not subtle.
Cassius: You’re describing a physiological approach to what knowledge is. I certainly think you’re right. Martin, are you comfortable that we’re sufficiently describing what it means to know something?
Martin: I couldn’t even tell — no.
Cassius: Maybe we should ask: are we talking about knowledge as a general concept when you say it’s a feeling? How do you relate your definition of the feeling to a particular thing that you know?
Elaine: For me, my feeling of certainty comes from observations that are dependable, that can be replicated, where there’s predictability — which all goes with materialism. I’m going to believe something is real and true if you can show me it’s consistent, there’s a mechanism, it’s going to happen again tomorrow the same way unless conditions change. Accuracy, dependability, reliability of observations — that is going to give me the sensation of knowing.
Martin: I have to agree with that, especially the materialism part. If we can think of something as knowledge because of our certainty, then by materialism it would have to be something rooted in our physiology or our minds.
Cassius: I need to move the discussion along and ask again: what is truth? Most people will say they know something is true. What does it mean to know something is true?
Elaine: It’s still caught up in that same sensation. Those words are not totally separate. But for me, what’s true is what is reliably, observably confirmable with sensory observations. I’m going to believe it’s true.
Martin: It depends on where. If I see a truth table from logic, I know what’s written there — the conclusion — that is the truth. That is the obvious part. And how well that matches our world is irrelevant for that. Like a logic problem is different from reality. With empirical things, the data will give with some more or less known probability what is considered to be the truth.
Cassius: Why don’t we go forward into the second paragraph. The first sentence says “knowledge of truth is originally derived from the senses.” Do we all agree with that?
Elaine: Yes. That’s how the human brain typically works — whatever that function is that gives us the feeling of certainty has to act on sensory input. We’re not getting information about the outside world any other way except senses and feelings.
Cassius: And the follow-up point: “whatever is able by evidence of an opposite truth to convince the senses of falsehood must be something of greater certainty than they.” Meaning: if you’re going to say something can contradict the senses, you’ve got to have greater certainty from that outside thing than from the senses. And Epicurus says there is no such thing.
Charles: You’d have to use your senses to get that certainty, right?
Cassius: Right. And I remember there’s a statement somewhere in Book One: if you cannot be certain about things that are directly in front of you, how can you be certain about anything?
Elaine: He doesn’t bring in religion here, but I want to mention it — there’s a really interesting book called Faith Versus Fact by Jerry Coyne that talks about the totally different tack religion takes versus science. Scientists want multiple observations before accepting something as most likely accurate, but in religion you get bigger brownie points if you believe something not only in the total absence of sense evidence but in contradiction to sense evidence.
Cassius: That’s the point about “I believe it because it’s absurd,” right? Didn’t somebody say something like that?
Elaine: Oh yes — Tertullian. Yeah, so the materialist point of view says you should derive knowledge from senses, but some religionists will say you should ignore the senses in favor of belief. And what can be of greater certainty than the senses? A religionist wouldn’t have any problem saying “yep, you’re right, I have something that overrides all my senses — I have faith.”
Charles: You have faith, but there’s another avenue: that you were born with innate knowledge from when you were with God, and you spend your life studying mathematics and logic so that you can be like Plato and know geometry — and then become a kind of priest of the absolute ideal.
Cassius: That ends up being pretty close to religion. Let me make sure we don’t miss the very last sentence in that paragraph: “therefore, whatever the senses at any time discover to us must be certain.” That is one of the major criticisms that superficial people make of Epicurus — that he said all sensations are true and people say “obviously they’re not all true, illusions happen all the time.” But if you read Lucretius, you’ve just spent significant time laboriously going through a whole list of illusions. Obviously Epicurus knew that illusions are part of life. But that doesn’t mean the senses are wrong — it’s the judgment. Go ahead, Elaine.
Elaine: I do want to say where he has “can the ears correct the eyes” — that each sense is separate and has distinct powers — that’s actually not quite neurobiologically correct. There are plenty of people like me: I have lexico-emotional synesthesia, so I get sensory impressions from feelings and some words. And there are other people who see colors when they hear certain pitches. In their brains, even if the eyes and ears are physically separated, there’s no way for them to experience their senses separately. It’s not a stepwise process. Not to mention the connection between odor and taste — during the coronavirus, we’ve all become educated about how when you lose your smell, you lose most of what you think of as taste. And even for typical people, studies show food will taste differently depending on what color plate it’s on, or even what temperature it appears to be. So there’s a lot more mixing of the senses in perception than Lucretius was aware of. Also — he would have to amend this — sound is sound waves, it’s a vibration, it can affect our bodies through other means. If you hear the bass from a loud radio in the car next to you, it makes your bones rattle. So you can feel sound as vibration through vibration receptors. To me, if something is real, there would be nothing to rule out that it could affect other sensory organs.
Cassius: Maybe the comment to make right now is to go back to the first sentence: “whatever is able by evidence of an opposite truth to convince the senses of falsehood must be something of greater certainty than they.” So regardless of how modern physiology talks about the relations between different senses, what is of greater certainty than the senses even under the latest scientific research? Is there anything?
Elaine: Not for a materialist. Because certainty is a sensation. Religionists get a strong sense of certainty based on what they’ve been told since they were very young, and believing it gives them a sense of belonging with their community — so they have linked it with this neurological sense of certainty. And it’s tight — it’s hard to disrupt that.
Cassius: You’re saying a religious fanatic could, in fact, get a greater sense of certainty through their religion that overrides the senses.
Elaine: That’s what I observe. But because I’m a materialist, I’m observing this happen — and that points us back to the direction of how we have to clearly talk about our systems and our definitions. While I’d certainly agree that the emotional sense of certainty of a religious fanatic could be greater than the sense of certainty of Martin when he evaluates an equation in his engineering office, I would not grant that the religious fanatic is in fact more certain of a fact than is Martin.
Cassius: Then you would need to point to what actually reinforces each feeling of certainty and what can be held up to scrutiny. Is there something behind the faith besides just individual affirmation, or is there something tangible and observable and repeatable?
Elaine: Observable and repeatable — so there are two different things. Does a person’s sense of certainty line up with observable, repeatable, predictable phenomena? The only way I know of to have your sense of certainty line up with observable, repeatable phenomena is to use your senses and not logic or faith. But if their goal is something different — if they think there’s a truth that has nothing to do with observable, repeatable phenomena — they’re just defining truth differently.
Cassius: Martin, nobody’s going to dispute that the feeling of certainty a religious fanatic might have could be stronger than the feeling of certainty of a scientist experimenting in a laboratory. And we as materialists — we’re not going to rank our view of certainty by the strength of the feeling, are we?
Charles: Well, somebody very religious might say whenever they think about their faith they get this confirmation, this feeling of certainty, and to them it’s very repeatable and predictable and something they can observe within themselves. So they might want to disavow empirical evidence or even reasoning entirely.
Elaine: And our ultimate position is that these are decisions for the individual to make. Although I would say that faith, to develop at all, requires social pressure — it’s not something I think people arrive at individually. A supposed miracle being witnessed by ten very religious people — I’m not going to put much weight on that.
Cassius: I’m going to move the discussion toward a close, but I want to put in the main section that we haven’t touched on: this passage is written in a philosophical context in which other Greek philosophers had basically attacked and undercut the senses as a reliable source of knowledge. Plato and Aristotle in particular had pointed to logic as the ultimate means of knowledge and asserted that you really could not consider something to be known unless you could put it into a logical proposition or syllogism — which I gather was one of the reasons Plato put “let no one who does not know geometry enter here.” Elaine?
Elaine: You said the word “reliable,” and that is what I would focus on. The only way to get reliable information that I know of is to use the senses. If reliability is what you need — if you want to know what’s really out there in a reliable way — you can’t use logic, you’ve got to use observations. I think we can prove that logic is not as reliable as the senses.
Cassius: Martin, Charles? Any comment?
Martin: Not really. I agree.
Charles: Yes.
Cassius: I personally don’t use the word logic in quite the way Elaine and Martin are using it. I use “logic” to imply that if something is logical, it is grounded in evidence of reality. I know not everyone uses the word that way. And I would use “reason” similarly — “true reason” as Lucretius uses it. Something to be reasonable or logical has to be grounded in the evidence of the senses. Elaine?
Elaine: I would recommend you consider dropping that usage. I know a guy who insists on using the word “religion” to refer to sets of cultural practices and insists belief is not part of it, and it makes all the atheists mad because he’s using the word differently. So I’d recommend grabbing a different word.
Cassius: I cannot agree to that suggestion, because you’re not referring to the source of all knowledge — which is Star Trek, the original series. When I think of logic, I think of Mr. Spock. And Mr. Spock as a logical Vulcan was not really too much involved in playing with premises or syllogisms or dialectical reason. He was always attempting to follow reason and to follow the evidence in front of him. So I think the cultural context of today has a different definition of logic than you’re using.
Elaine: There are so many multiple connotations of the word logic, but for almost everybody that I know, it includes abstraction inevitably — and so you can’t rely on it. It’s not as reliable as observations. So I’d focus on getting good evidence. I want, instead of atheists having a day of reason, I want them to have a day of evidence — because reason is super tricky, it’s full of pitfalls and mistakes.
Charles: To use a contemporary reference, the way I kind of see it, Cassius, is kind of how the “facts and logic” crowd uses the word logic. I think Elaine is right from a technical point of view and Martin from a professional point of view — when you go to college and take a course in logic, you’re taking a course on syllogisms and induction and deduction and so on. But from my experience, the people down at the 7-Eleven use the word logic relatively frequently and I don’t think they look at it the same way as the formal definition.
Cassius: They’re using it the way I’m using it though?
Charles: Oh yeah. They see logic as broad and abstract, leaving out the nitty-gritty details and overlooking exceptions — discounting real world variables. And they also see it as discounting feelings as part of reality. That’s where Spock would usually go wrong.
Cassius: Yes — that’s the distinction I draw. But you are slandering the name of Mr. Spock! On feeling, you’re right — he was devoid of feeling. But in terms of his processing power, he was the most data-driven of the people on the original series.
Elaine: You can’t say that as long as he was ignoring feelings, because we get evidence of other people’s feelings through our senses, and he was missing that.
Martin: You can apply logic to empirical data, but then it’s no more purely logic. You just use logic as a tool to deal with empirical data — that’s a combination which is okay, but logic is separate and independent of reality.
Cassius: I’m thinking I’m actually agreeing with that. Go ahead, Elaine.
Elaine: There are so many connotations of the word logic, but for almost everybody that we might be trying to convince, it includes abstraction inevitably — and so you can’t rely on it. It’s not as reliable as observations. And when you make that statement about logic, would you make the same statement about the word “reason”?
Cassius: Would I? I think Lucretius uses the phrase “true reason,” and if something is reasonable or logical in my definition, it has to be grounded in the evidence of the senses. So I see multiple definitions of these words at play.
Elaine: Yeah. I want — instead of atheists having a day of reason — I want them to have a day of evidence. Because reason is super tricky, full of pitfalls and mistakes. I would focus more on getting good evidence.
Martin: For me, reason is somewhat softer than logic. In logic you need statements which are absolutely true to come to new statements which are also absolutely true. But with reason you don’t need this, and you don’t have this absoluteness. Reason can lead you to wrong conclusions if the empirical data you start with is incorrect. Someone who doesn’t really understand formal logic can still use reason properly because it somehow mimics logic — but it doesn’t have logic’s absoluteness.
Cassius: Let’s begin to draw today’s discussion to a conclusion — it’s been one of the best ones I think we’ve ever had. So if we begin to come to a conclusion, what would everyone like to say in closing? Martin, go first.
Martin: I would just regurgitate something I’ve already said. The most important thing: stuff about certainty — that it’s a sensation.
Elaine: Yeah, I think that’s important. To me, as materialists we value reliability of observations as telling us what’s really going on. If you’re a person who shares that preference for being able to predict what might happen next or get reliable information, there’s no better way to get that than by being a materialist and making sensory observations.
Cassius: Well, thank you everybody for the discussion today. We’ll come back to this next week because the remaining section of text we had for today is going to go over these very same issues and talk about the implications. So we can think about what we’ve said during the coming week, and we’ll post this to the podcasting locations. If anybody has any comments or questions, please let us know and we’ll try to include them in the next episode. So with that, we’ll close for the day. Thanks everybody for your time.
Elaine: Thanks everybody.
Martin: Good week.
Charles: Bye bye.