Introduction to Philosophy & Logic (1999)
12. Name and Speech, and Aristotle on Learning from Pre-existing Knowledge: Syllogism, Induction, Enthymeme, Example
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[0:00] So, in a way, the two fundamental definitions of logic are the definition of name and the definition of speech. Okay. Now, the definition of name and of speech in logic are the same in most of their parts,

[0:28] but one part is different in each. Okay. So a name is first of all a sound, okay? And a speech is first of all a sound,

[0:47] okay? That's the fundamental word. It's a sound. Okay. Now it's a sound produced not by my fingers rapping on the desk, right? But it's a sound produced by the vocal cords, right? Okay.

[1:05] Now, the little boy, he starts to say, professors always clear your throat when I clear my throat, do I intend to signify something by that sound that I make? So I can speak more clearly.

[1:22] But the name or the speech is a vocal sound that what signifies, right? I mentioned already the definition of sign, right? Which is the one that goes back to Augustine, right? And I translate the definition as two parts: that which strikes the senses and brings to mind something other than itself. Okay.

[1:58] Now, the fourth part of the definition, sound is the first part, right? Vocal is the second part. Signifying is the third part. Now, the fourth by the definition now the fourth by the definition, we say sometimes it signifies by custom. Or by agreement,

[2:23] as opposed to by nature. Now, what are you separating the name of speech from when you add by custom or by agreement? Things like moaning or sighing. There are certain vocal sounds that signify by nature, like a groan, right? So, if you kick somebody in the stomach, they groan, right? And you can recognize that groan around, right? If someone attacks you in the dark, you scream or something, right?

[2:57] Or the baby's cry, right? The baby's cry signifies something. Kind of kind of funny, you know. Somebody gave me a little book on dads, you know, huh? And one of the, items there was kind of funny, huh? The new father, right? first time father. he's leaving the hospital, you know, his wife and the new baby, right? And he, he's very concerned about doing the right thing, So he says to the nurse, you know, now, when should we wake the little fellow?

[3:29] I realize that he's going to be taking over their life for a while. And but notice, huh? It's by nature that the what baby signifies, right? That need, right, for food, and maybe need the diaper changed, and so on. By crying, you know, okay.

[3:57] That's when you first, you know, when you first see the baby, you start to look before and after. I noticed when the baby would cry in the night, the first thing we do is what change the diaper, right? Then the baby would get fed, right? Oh. Okay. And the baby would cry through the whole change of diaper until they got their food, right? But after a while, once they went to the changing table, they stopped crying.

[4:18] Oh man. Like they knew that. it's going to be followed. Yeah, looking before and after is going to be followed by food, and they tend to solve their needs, right? So they don't need to keep crying anymore, right? Oh. Okay. So those four parts are common to the definition of name and speech.

[4:39] But now the last part separates name from speech. No part of which signifies by itself. That's the fifth part of the definition. No part of which signifies by itself. By the last part of the definition of speech is having parts, and that means what at least two parts. That. Signify

[5:20] by themselves. Okay. So man, for example, is a name, right? Man is a vocal sound. It signifies by custom, and you know what it signifies. And no part of man signifies anything by itself, right? Now you can have parts in a name, like animal, right? Animal has three what syllables, right? It's a vocal sound, right? Signifying by custom. It's not by nature. The Greeks would say zoon.

[5:59] But no part signifies by itself, and in law, does each syllable signify something? No, it's only the whole name that signifies something, right? Okay. And so the logicians' analysis of language goes down to the name, but not below that. He's interested in vocal sounds only in so far as they what signify, right? But the grammarian goes all the way down to the letters and to the syllables, right?

[6:29] And the poet will go down to the letters because he wants to what rhyme and alliterate, and he's going down to syllables because he wants meter and so on, right? Logician doesn't care about that, right? This is the smallest thing for him. But speech has parts, and these two that signify by themselves. So white man is an example of speech, right? Man means something by itself, and white means something by itself, and the whole white man, right, depends upon the meaning of man and white.

[7:05] But the meaning of animal, though it has more syllables than white man, it doesn't depend upon the meaning of a n and i and m a l, right? Okay.

[7:16] And notice, huh? Even if a name was put together from two other names, right? If it's functioning as a name, its parts don't mean anything by themselves. So you've called me Bergkvist, right? Originally, we had a G in there, so we were called Bergkvist. In fact, some of my uncles and uncles and aunts still have the G in there. My father was Swedish and chopped it out.

[7:40] Never got the full explanation why he did, right? But Berg in Swedish means what? Mountain. And Kvist means branch, right? See? But in my name today, Bergquist, and they had the G in there. Would these two parts mean something?

[7:57] No, it's functioning as one name, right? Or I know a woman whose last name was Johnson, right? Right. Well, she wasn't a son, and her father wasn't John, right? Okay. So Johnson is not what A speech, right? It's only the whole sound, right? That he. Yeah. In a statement, in syllogism, or argument in general, definition is always a what?

[8:32] Speech. Okay. A statement is always what? Speech, right? It has parts that signify by themselves, huh? So when I give the definition of square as an equilateral and right-angled quadrilateral, well, quadrilateral means something, right? Equilateral means something, and right angle means something, and the meaning of the whole definition depends upon the meaning of those parts, right? When we define reason as the ability for large discourse, looking before and after, well, before had a lot of meaning, right?

[9:09] Looking has meaning right by itself, right? Discourse, large, each have meaning by themselves, ability does, right? Okay. So a definition is never just one name; it's always a combination of two or more names. A statement now is a speech, right? Man runs. Man is an animal, right? Man means something by itself. Runs means something by itself, right? Okay. Man is an animal. Man means something by itself.

[9:39] Animal said by itself. Man is not a stone. Man means something. Stone means something by themselves, right? And the meaning of the whole depends upon the meaning of the parts. Parts right Nay for its story an argument is going to be composed of two or more statements, right? Usually two statements. So it's going to be what? Speech, right? So we could say that logic, in terms of its end, it's about three acts of reason, right?

[10:09] But as a subject, it's about mainly the three speeches that perfect those three acts: definition, which perfects understanding what a thing is; statement, which makes possible understanding true or false; and syllogism, or some other kind of argument, makes possible reasoning, right? Okay. But when we examine these speeches, we'll see the names that they're put together from, right? Okay. And so we studied the names even before the what?

[10:46] Definition, right? And before the statement. Okay. Yeah, I just want to make sure. I got that. So the subjects of logic are the tools. Yeah. Okay. Yeah. Okay. And chiefly definition, statement, and syllogism, take the name Sorry. It's perfect And you call name and speech two fundamental definitions. Definition. Well, I mean, two fundamental things we talk about, right? Yeah. Okay. So the work of of Of Porphyry, sometimes called the Book of the Five Names, and the categories is called the Book of the Ten Names, and actually in the Greek they'll say you know the five vocal sounds and the ten vocal sounds.

[11:38] Okay. So we're going to be studying then three main speeches. Let's look at this last text of Aristotle here, which is a little bit of a breakdown here. This idea of the third actor in page six now.

[12:13] He says, all teaching and all learning by reason come to be from pre-existent knowledge. Well, this ties in with what we saw about the word discourse, right? We defined discourse in the definition of reason as coming to know, right? The unknown through the known, right?

[12:33] Aristotle is now looking at this in regard to reasoning in particular. This is clear to those looking at all. For the mathematical forms of reasoned-out knowledge come about in this way in each of the other arts. I take the mathematical forms of reasoned-out knowledge, geometry, arithmetic, as the most clear examples of what demonstration, right? Okay. That's why Euclid used that phrase there, QE D, all the time, right?

[13:05] Okay. But notice how in the beginning of Euclid, you can kind of see the three acts of reason because he begins with definitions, right? And then he gives certain statements that are obvious from the definitions, like the postulates and the axioms, huh? And then he starts to what demonstrate, right? Okay. And so he demonstrates through the postulates the first theorem, right? And uses the first theorem to demonstrate the second theorem, and so on, right?

[13:34] And in each of these, you're going from the known to the unknown, right? So he he takes the parallels. He shows that when a straight line falls upon parallels, it makes what the alternate angles what equal. These two are these two. Right. Okay. Then later on, he's reasoning. I'm going to change the demonstration a little bit here. He did a couple things. If you wanted to show that the triangle has its interior angles equal to right angles, you could use this draw a straight line through there parallel to the base.

[14:13] Then, by this previous theorem, you'd know that these two were what equal. The alternate angles. And these two here would be equal, so these two equal those two. That's the third one. So add up two right angles. So coming to know, right, in a very rigorous way, right? Something you didn't know, what you didn't know, right?

[14:40] How do you know these two angles are equal, right? We know already that when a straight line makes a straight line, it makes either two right angles or angles equal to right angles. So

[14:56] a plus x must equal two right angles, right? Because this is a straight line meeting a straight line, basic, isn't it? And b plus x must also be equal to two right angles.

[15:12] Lines equal to the same or equal to each other—that's one of the axioms, right? Have to equal to each other, and then equals subtract from equals, another axiom. Resulting equal, right? So your reasoning to these angles being equal from this previous theorem—that when a straight line meets a straight line, makes two right angles, or angles equal to right angles—and quantities what equal to the same, equal to each other, and equals subtract from equals, result equal, right?

[15:39] So it's clear that he says in the mathematical forms of science, at least, right, that you're knowing coming to know something to knowing something else, right? But in a very rigorous way that we call demonstration, right? Now, when Plato talks about this kind of knowledge that's produced by demonstration, which in Greek is called episteme, right? He does so in the dialogue called the Theaetetus, where Socrates talks with a mathematician about demonstration.

[16:11] Now, there's usually a connection between the guy that Socrates talks to and what he talks about. So he talks about courage with Laches, Laches, who's an old what general? Presumably, knows something about courage, right? He talks to Euthyphro about piety because Euthyphro is prosecuting his own father for impiety, right? So he should know something about piety. But he talks to Theaetetus, the you know mathematician, about what demonstration, right?

[16:46] Aristotle's talking touching upon that first kind of reasoning that we talk about in the prior posterior analytics, right? Which is most easily seen in mathematics, huh? Okay. And then he goes to the Socratic conversations, which are mainly dialectical. And likewise, in the conversations, sometimes Socrates reasons by syllogisms, and then those by induction.

[17:16] For both teach through what was known before. These taking from what is understood, and that's something universal in the syllogism. And those, the ones by induction, showing the universal through the singular, that is clear.

[17:36] Yeah, the word dialogue means Plato. The word dialogue is a Greek word for conversation. So sometimes Socrates argues by a syllogism, right? He says, "Simmias has argued that the

[18:02] soul is the harmony of the body." Right. Socrates says, "Well, the soul resists the body sometimes." Okay. And doesn't. Always follow the body, the soul resists the body. But the harmony of the body

[18:27] does not resist the body. So if the soul resists the body, but the harmony of the body wouldn't resist the body, then the soul is not what. Yeah, this is a syllogism, right? Okay, and the syllogism is defined as a a speech in which some statements laid down, another follows necessarily because of those laid down. Okay, so if you lay down these two, then it follows necessarily that the soul is not the harmony of the body.

[19:14] So sometimes Socrates syllogizes, and he doesn't really state the definition fully, but he he will say this follows necessarily from that, right? So he has the general idea. But then Socrates wants to reason for the proposition that change is between contraries, right? And the first way we show this is by induction. We say, what is it that dries up?

[19:44] What is it that's moistened? The drought. Yeah, you can't moisten the ocean, and you moisten something that is dry. What is it that's hardened? Soft. What is it that's softened? Yeah. What is it becomes healthy? Sick. Sick. And who becomes sick? Yeah. So he's showing in many particulars, right? Something that he wants to say generally, the change is between opposites, right? Okay. So that's the other kind of argument called induction, right?

[20:20] That's an argument from many particulars, right, to the general. Yeah. But here he's starting from something more general, seen by the syllogism. Where is that from? This is from the Phaedo. Actually, it's two syllogisms there. He destroys the position of objection Simmias just based upon suggestion, but not proof that the soul is the harmony of the body.

[20:50] He's shown before that there's a harmony of the soul, but there's not a harmony of harmony. Therefore. The other harmony depends upon another harmony. That the soul existed before the body, right? And the harmony doesn't exist before the body. Okay. But notice, huh? These syllogisms are not always what.

[21:15] Demonstrations, huh? Because maybe some of the premises are only what probable, right? Okay. Socrates has given a probable argument that the soul existed before the body. The harmony of the body doesn't exist before the body, therefore the soul is not the harmony of the body. But maybe that statement is not even true that the soul is before the body. But it's probable, you know. Socrates is given an argument for it, right?

[21:43] So he syllogizes from that that the conclusion is not necessarily true because one of the premises is not necessarily true, right? So Socrates will reason either by syllogisms or by inductions. The reason why you do this in dialectic is that you're concerned with knowing something about the universal. And one way of knowing something about the universal is by induction from the many particulars, right? The other is by syllogism.

[22:14] Now, in the same way, speakers persuade. Now he's thinking of rhetoric, right? The art of persuasion. For they do so either through examples, which is induction, and not simply induction, but it has a resemblance to induction, or through enthymemes, which is in a way like a syllogism. In what way is example like an induction? Well, example here doesn't mean a singular used to illustrate something. That's another meaning of example.

[22:43] But here, example means an argument from one singular to another singular of the same kind. Okay. So a friend comes to town. He wants to eat in a good restaurant in Boston, right? Years ago, so my wife and I had had a wonderful meal at Joseph's restaurant. So let's go to Joseph's. Okay. I'm reasoning from the wonderful meal my wife and I had at Joseph's to what the meal that he and I could have going to Joseph's.

[23:22] So you buy a particular car and it lasts a long time. So you buy another one of that same thing. Is it going to necessarily be good? No, no, no. Is the meal going to necessarily be good? No, no. My wife and I went on Saturday night, and my friend and I went on Monday night. Probably not the same chef. But the more the two are alike, the more you can reason from one to the other, right?

[23:54] MacArthur was defending the Inchon landing. you know, that chiefs of staff were opposed to it and so on. And he compared what he's going to do to what Wolf's landing in Quebec. huh? No one thought Wolf could land where he did, right? But Wolfe had stayed very closely, and he could climb up a particular place, right, and surprise the French and. Led to the taking of French Quebec, ending of the French and Indian War, right?

[24:18] So, now notice induction, an example is a little bit like induction because, in a sense, saying taking the last meal, the meal I had it, it shows us, right? As kind of what representative of meals it shows us, right? It's a very perfect induction. I had one or two meals, there, maybe, right? You see, so that's something of the induction, but not as the strength of induction, which is from many.

[24:48] So the scientist often bases himself upon an induction, but he's cut open hundreds or thousands of frogs, right? And they all have three chambered hearts or whatever they have, right? I've eaten maybe this restaurant two or three times? You know, or you know only once.

[25:10] Now, what's an enthymeme? huh? An enthymeme is an argument from what, likelihood or from signs? Boys will be boys. Any exceptions to that? Now, sometimes you read the newspaper about a boy who did what? you expect a man to do, right? Yeah. So, likelihood falls short of the true universality of the syllogism, right? See, if I have a syllogism like this, uh

[25:54] we say uh No odd number is either. And every three is odd. there's an odd number. It's going to follow necessarily that no three is what even, yeah.

[26:25] Notice that complete universality, universality here, universal negation, right? No odd number is even. And for knowing what an odd number is and even number, I can see that, right? Okay. But now, if I say boys will be boys, he's only a boy, therefore he's going to act like a boy, right? Does he have the same nerve? No, because sometimes a boy, you know, like the Dutch boy, put his finger there and saved the dyke, right?

[26:52] Sometimes a boy does something, right? Protecting the mother when the father's away or something like that, right? We read about this in the paper, right?

[27:01] Um. It's difficult in human affairs, you see, to take propositions that are true universally. Right? Return what you borrow. Right. In some cases, you shouldn't do this. Right. So there's some exceptions. So the enthymeme will proceed from likelihood, but likelihood lacks the true universality of syllogism, Aristotle says it's a syllogism in a qualified sense. Right? It's like the syllogism, right? But it has a kind of universality, but not complete universality.

[27:47] Or he argues in the end to me, from signs. huh? Now, the most common sign that you have in rhetoric is a sign that's more universal than signified.

[28:01] So, if a man comes staggering out of a bar, what would you conclude? Drunk. Sign that he's drunk, right? But does everybody who staggers drunk? Say, sometimes they have a physical defect, right? Sometimes. They are what? Just tired, right? You know, so we go down to the side of the wall. They go down to bed, right? You see. And

[28:29] your eyes being bloodshot, you know, that sign you've been drinking. One time the state trooper stopped me. I was driving. I was driving about five miles over the speed limit. I was coming down from Quebec, and it's like an eight, nine-hour drive. It's coming straight through, you know, It's nighttime, you know, the lights in your face. So he stopped. me, he's giving me no warning and so on.

[28:49] Then he went away and looked back at me. You know, my eyes. He says, "You were drinking." And I said, "No, I drove down from Quebec today." he said, "well, go to Dunkin' Donuts over here. Get yourself some coffee." But the point is, you see, you must stop people who are going a little bit over the speed limit or pot, right? And he recognized certain signs. I've been drinking, right?

[29:10] But my eyes were what? Something else, right? Yeah. So, remember one time I had a student come to class. He had got long, shaky hair, you know, and so on. And so he comes to day one day in class, and his hair is all cut real close, and so on. I said, "I see. Get your haircut." He says, "Yeah." I told you what happened, right? He got in some kind of an accident, and he was defending himself.

[29:37] And he came down to the courthouse to go to one of the offices. And cops saw him. He said, "You're in the drug charge to go over there." Oh. And says, "I'm not going to go here at court, looking like a druggy. He said, I mean, the point is, these, you know, we all recognize signs, certain things, right? You know, I was staying downtown in a street corner one time in Worcester, and I would watch the cop there.

[30:05] You know, kind of follow somebody on that thing. I said, "It'll be fun." Then, closer, you see a bulge or something, you know, like a gun or something, right? The way you pick those things up. One of my wife's friends is married to a top policeman here, the city detective. You know, he could pick out a prostitute. You know, two or three blocks down. That's by the way that they walk, you know.

[30:26] Say, but you can't always. These signs are not what universal, right? So an enthymeme is an argument from likelihood or from signs, but there are certain what exceptions, right? So it doesn't have the rigor of the syllogism, which requires true universal, you know, in the major premise. We'll be coming back to these forms of argument. I just started sticking that little text of Aristotle here to take up argument.

[30:59] But notice the emphasis in that text of Aristotle was on argument, right? Reasoning. Now, in the text of the Metaphysics, he's talking about the same thing, but he points out that this is true about what definition, right? Okay.

[31:19] It happens to the one learning geometry to foreknow, but he knows nothing before of that which there is reasoned out knowledge, and about which he's going to learn. But that through which he's going to learn, right? Contrary to Socrates' view, for all learning is through the foreknow. Either all, as Thomas explains, universal, or some, the particular. Both that by demonstration and that by definition, son.

[31:50] I might mention apropos of this, that when Albert the Great divides logic, he divides it not into three, but into what? Two, the art of defining and the art of reasoning. And the art of defining is about the simple unknown, he says, right? How you come to know it, and the art of reasoning about the complex unknown. Okay. But then the consideration of statement he makes a part of the art of what?

[32:18] Argument, right? Okay. While Thomas divides it into what three? If you go back to a dialogue called the Mino, corresponds to Albert the Great's division, because the Mino has three parts, son, and the first part is about defining, the third part is about reasoning, the middle part is about what's common to the two. Common to know what you don't know, so in a way, Albert is closer to what Plato's what division there, right?

[32:56] And but Thomas is looking at the works of Aristotle. It was called the father of logic, and he sees they fall into these three, right?

[33:07] I'm sorry. I didn't follow how the Mino and the division of three fits with Albert's division of three. Well, the Mino has two parts, or three parts, huh? Right. And the first part begins with Mino's question: "Can virtue be taught?" Right? It's acquired some other way. And Socrates says, "I don't know." Furthermore, I don't even know what virtue is.

[33:33] And so they get into a discussion of what virtue is. Socrates says, "No, not anybody knows what virtue is." Mino says, "I know." So they have a conversation, and Mino has a hard time defining virtue. It doesn't really succeed, right? So that first part is a kind of introduction to the difficulty of defining. Defining, okay. Now, in the third part, Mino comes back and he wants to know whether virtue can be taught, still, even though he doesn't know what virtue is exactly.

[34:04] And Socrates says, "Well, we could discuss better whether virtue can be taught by defining virtue, but since." You're not willing to do that. I'll try to talk about whether virtue can be taught, by going to look at both sides And he argues for and against, dialectically. Now,

[34:30] that third part was an introduction to reasoning, And Socrates distinguishes between knowing the sense of being certain and opinion, right? Yeah. Even a true opinion, right? So he's making the distinction in a way between demonstration and dialectic, yeah. So, but the middle part of the dialogue

[34:53] begins with Socrates wants Mino to go with him and explain, or try to find out rather, what virtue is, right? And Mino says, "Well, how can you investigate what you don't know? You know, you don't know what you're looking for, so how can you go looking for it? " So, and Socrates tries to reply to that, right? I think it's a trouble replying to it. So, how can you direct yourself to what you don't know?

[35:23] Reasonable guess. Because if I tell you how do you get there, I go to the you know gas station and say how do you get there? Where are you trying to get to go, buddy? Right? I can't tell you how to get there. Let's know where you're going. Yeah. So, how can you direct yourself to what you don't know? That's really the problem of the middle part of the dialogue.

[35:47] See, but both in defining and in reasoning, you are directing yourself to what you don't know, and how is that possible, right? So the middle part is really about what's common to defining reasoning, and even to counter-intuitive, right? How can we direct ourselves to what we don't know? We don't know it. And see, logic is about you know using what you do know, right, to come to what you don't know, right?

[36:21] Yeah. But how do you know what to use? You know what you're trying to get to. See, and Aristotle, you know, alludes to the Mino there in the beginning of the *Posterior Analytics if you read it, huh?

[36:36] But Socrates gets into a difficulty. Mino's objections, based upon you know sophistical kind of argument, which I'll take up later on, and Socrates commits the very same kind of mistake when he tries to answer Mino.

[36:52] So Plato has artfully, right, separated a introduction to the art of defining and the art of reasoning by discussion of what's common to the two. So if you know Albert the Great's division of logic into defining and reasoning, right, and Oesterle used to use Oesterle's logic book years ago, but the name of the book was Logic, and the subtitle was. The art of defining and reasoning. So it's following Albert the Great's division, but that goes back to Plato there, in the, or Socrates in the Meno right But Thomas, when he divides Aristotle's works.

[37:30] he divides them into what three, okay? And they just seem to be learned from both divisions, right? But in order to keep it into two,

[37:45] Albert has to put the art about statements, the logic of reasoning, right? And doesn't see the one, two, three there as well as Thomas does. But it's not impossible to divide what? The same thing in the two and three, right? Like we're mentioning about the creed, right? Yeah. The the Nicene Creed and Apostles' Creed divides all the articles of faith into three, but the Athanasian Creed. and the Creed of the Fourth Lateran Council, divides all the articles of faith into two.

[38:28] The Nicene Creed divides it according to the Father, the Son, the Holy Spirit, and they group all the you know articles around either the Father or the Son or the Holy Spirit, right? But the Athanasian Creed, so called, in the Creed of the Fourth Lateran Council, they divide it according to the humanity and the divinity of Christ, and they group them all: six articles of humanity, six articles with the the divinity.

[38:58] Both divisions make sense, but the Nicene Creed emphasizes the Trinity, right? When Peter makes his profession of faith, he's following the other division, isn't he? The Christ, the Son of Living God, that's a complete profession of faith, and and that's why the church is built upon that.

[39:26] Aristotle divides the what the plot into beginning, middle, and end. He divides it also into tying the knot and untying the knot. Both divisions make sense.

[39:42] Sometimes I divide the family into the parents and the children.