Notice: This log copyright 1995 by Pankaj Saxena and Tom Wright. Reproduction without prior permission is prohibited. All statements starting with > were made by Tom Wright Session Start: Fri Oct 20 23:00:47 1995 Today's topic is Logic: Induction and Deduction. Briefly, this is what I would like to cover: 1. Definition of Logic, Induction and Deduction. 2. Basis of Logic - Law of Identity and its corollaries. 3. Induction: How is induction justified? What is inductive knowledge? What degree of certainty does this knowledge have? What happens when this knowledge expands? 4. Relationship between induction and integration. 5. Deduction: differences between knowledge obtained through deduction and induction. 6. Flaws in modern logic. Before we begin, I'd like to present some definitions: Logic: the art of non-contradictory identification (of some fact of reality). Induction: The process of reaching general conclusions from specific facts. Deduction: The process of deriving specific inference(s) from general truths. Now I'll open the discussion by asking the first question: why is my definition of logic valid? What is the basis of logic? The axiom of identity implies non-contradiction: metaphysically. What are the corollaries of the law of identity? And all questions can be re-cast into the form: "What is _____?" I'm not sure what you mean. You need more information to draw a corollary, right? Okay. So logic is based on the law of identity. The law of identity states that A is A. Logic identifies A. Correct? Will: No. A corollary is a subsidiary truth. That is, if "X" is true, then "Y" must be true because it is implied by "X". It is the method that is based on A=A, and only a method based on identity can identify. The law of identity has as its corollaries the laws of non-contradiction, and the law of the excluded middle. Aren't those both the same as Identity? What's the law of the excluded middle? Will: right, they're corollaries. Non-Contradiction: A cannot be non-A. Excluded middle: either a thing is A or it is non-A, never both A and non-A, or neither A nor non-A. Okay. So the basis of logic is identity. Things have some identity, and the purpose of logic is identification. A better way to state the law of excluded middle is: either a proposition is true or it is false. It can never be both true and false, and never can be neither true nor false. (Given the context of non-arbitrary statements.) Does anyone have any problems with my definitions of inductiona and deduction? -a Subetai, could you repeat them? I can repeat the whole thing, not parts. Before we begin, I'd like to present some definitions: Logic: the art of non-contradictory identification (of some fact of reality). Induction: The process of reaching general conclusions from specific facts. Deduction: The process of deriving specific inference(s) from general truths. Now I'll open the discussion by asking the first question: why is my definition of logic valid? What is the basis of logic? Subetai: I have a question about them: must one induce before he deduces? Gilles: I don't think so. I think one can deduce from both general and specific facts. Gilles, in what context? Anyone? And if one can deduce from specific facts, you didn't need induction there. Will: Subetai answered my question. Any problems with my definitions? Okay, then I'll move on to induction. Subetai: in that case, why is deduction defined as "the process of deriving specific inferences from general truths?" Subetai: A specific fact isn't a general truth, is it? Gilles: That's how it's defined in most logic books. We should add from "specific facts and/or general truths". Would that be okay? Subetai: Well, just to make sure, what would be an example of deducing from a specific fact? Gilles: Okay. Lets say "Mary went to the mall this afternoon". Can you deduce from that that "Mary wasn't at school this afternoon"? Subetai: Yes. Deduction is top-down. Induction is bottom-up. WillP: That's true in general. Okay, moving on to the nature of induction: Let's move on to the next question. Induction is the process of reaching general conclusions from specific facts. To use a common example, does the fact that the sun has risen in the east every day of my life justify the belief that it will rise in the east tomorrow? What do contextuality of knowledge and causality have to do with induction? I need a definition of general truths. Specific facts when coalesced (via induction) form truths, right? john: Yes, when integrated, they form a general truth. Like the law of gravity. Or any concept. So Mary's absense from school would also require knowledge of what constituted school's boundaries Subetai, not until you find a causal mechanism. john: It would require knowledge that school and the mall were two exclusive places. mutually exclusive Will: why? Were people wrong in believing that before gravity was discovered? more specific facts - aren't we building (by induction) general truths? john: Mary's example was an example of deduction from a specific fact. For building general truths, you do need induction. several facts Subetai, I think you can say that an events constant recurrence is a kind of knowledge. But before you can prove it is true that the sun will rise tomorrow, you need a causal mechanism. Otherwise the argument rests on: "it has happened every other day". Subetai: are axioms exceptions to that? Will: So you're saying that causality is required to prove the *necessity* of an event happening, while without it you are left with contingency? Gilles: No, axioms are the broadest generalizations. They require induction. Subetai, yes. I think that's correct. I don't think axioms even need induction. They are implicit in many forms of knowledge. Will: Can you have no knowledge with just contingency? Isn't knowledge contextual? wouldn't it be arbitrary to assert that it might not? you haven't seen it do otherwise. Will_P: But all knowledge needs induction, so underlying axioms are thereby induced. Subetai, I'm not certain in this area. Will: How can you form the concept "existence" without induction? Existence is an axiom. Knowledge is contextual. Without knowing the cause for something, you can still have knowledge. This knowledge would be circumscribed: (1) by the implied qualification "if no new fact is added". (2) by the assumption that non man made reality has no choice. That "is is" is the same as "it has to be". is is = it is So you could say that the sun will rise in the east *unless* some new fact is added. The assumption is that reality continues to be what it is. How's that? That doesn't require knowing gravity (causes). Do you have knowledge there without it? > Subetai: Of course I've got an errand to run. Brb. What do you mean by "knowing the cause for something"? Because the ultimate cause for something is the nature of the something -- and the nature of the something is its attributes, right? Wright: So knowledge does not depend on knowing the cause. But without knowing the cause, you have contingency (i.e., contingent that things continue the way they have), while knowing causes gives you necessity. sorry, that was for will, not wright Because in that case, it would be dangerous to try to distinguish between some pre-knowledge-of-cause knowledge and knowledge-of- cause knowledge. Am I explaining myself? Gilles: I mean knowing that gravitation causes the earth to spin around the sun counterclockwise, and so the sun will rise in the east. Gilles: I don't understand. Subetai: but that is just a wider, deeper knowledge -- it can't be put in a different category -- because you induced gravitation also. Gilles: exactly. It's not a different category of knowledge at all. Knowledge is always contextual, and you just have a wider context if you know about gravity. Subetai: The reason I brought it up was that Will said something about "not knowing the cause" of the sun rising. Which leads me to believe that he would complain about not knowing the cause of gravity. Gilles: okay. I think he was trying to differentiate between contingency and necessity, not imply that knowing about causality gives you a different *kind* of knowledge. Subetai: I think that type of comment implies some kind of desire for revelations. Gilles: yes it does, if taken literally. Subetai: But what is the sense of differentiating between contingency and necessity? In this context? Gilles: The sense is that with contingency you are ssaying: this will continue to happen if whatever is making it happen stays the same. While with necessity you are saying that I know gravity makes this happen, and therefore it will happen because gravity is a universal law. Why wouldn't it stay the same? Gilles: It would stay the same. That's because the assumption is that reality (non man made) has no choice to be other than what it is). That's why it's knowledge too. I was arguing that you could have knowledge without knowing about gravity in this case. Will said you couldn't. Can I take a break here to ask an unrealted question? Subetai: hey, it's your channel. :^) > Ghaki: Not exactly :) I've noticed that many people are not participating. Perhaps it's because the subject matter is not interesting to them, but if there's another reason (such as the discussion's too technical, not technical enough, etc.), I'd like your comments on that later. Subetai: I'd really like to ask one more question. Gilles: sure Subetai: what's the difference between knowing that the sun rises every day, and knowing that gravity is a universal law? Other than the fact that the second is more fundamental than the first? Subetai: I haven't done much thinking about logic, that's all. I am following the discussion though. Hello the channel! Gilles: The difference is that in one case you've established the *why*. Is that okay? Well, while we're on induction, I'd like to discuss one more term: "integration". modelled the *why* - doesn't this make this knowledge also contingent? What's integration? john: it's contingent on reality staying the same, which is not the same as saying that whatever unknown facts cause the sun to rise in the east stay the same. In one case, the unknown fact might be a spring winding down. integration - the assembly of parts to form a whole? > How about a definition to start out? Okay. Integration is the collection of related facts into a unit. This (as Rand says) implies more than a summation. the unit not being the aforementioned general truth, I presume? The examples she uses are: (1) integration of sensations into a perception (2) The integration of entities into a concept. > johnk: Integration is used in forming concepts.. for example johnk: Could be. That's why I'm asking what the difference between integration and induction is. Integration requires induction. What else? > You integrate the many tables that you have seen into the concept "table" re > Welcome back, Will Can the terms be substituted for each other? Induction is creating a new concept out of existing concepts (or perceived facts.) Integration is relating already existing concepts to each other. I guess that depends on whether general (as in general truth) is the same as objective > Hmm.. Ghaki: What about the integration of specific entities into a concept? Rand used that term there. > "The process of observing the facts of reality and of integrating them into concepts is, in essence, a process of induction." ITOE p. 36 Concept formation is induction, and that's a type of integration. But integration is also used to draw relationships among things in general, bot always with the purpose of forming concepts. bot = not So integration is a wider term than induction. ok, so induction is a subset of integration. Anyone have anything to add there? Okay, we're winding up our discussion. Let's talk about deduction. Deduction is the process of deriving specific inference(s) from general truths. Anybody like to add something to that? Gilles already pointed out that we can deduce from specific facts to other specific facts. I don't know if we're on a time limit here. I planned the discussion for an hour. It's almost over, so I'll finish with some comments on modern logic. Last item on the agenda: modern logic. Here's a textbook definition of logic: "The major task of logic is to establish a systematic way of deducing the logical consequences of a set of sentences". What's wrong with this definition? That's from _Brittanica_. it doesn't mention reality at all. Subetai, it is completely disconnected from reality- from percepts or facts. As I see it, they're reduced logic to a word game. The essential element of identifying the facts of reality is missing. Will, Ghaki: Right > Rationalism, in other words Here's another item from the same book: "Inductive logic, as it applies to logic in systems of the 20th century [..] is obsolete. The problems earlier subsumed under induction are considered to be concerns of the methodology of the natural sciences, and logic is generally taken to mean deductive logic." This is what Rand meant when she said "... if reason is to be destroyed, it is man's integrating capacity that has to be destroyed." Any comments? Well, that's pretty obvious. I thought I'd include that to show what the status quo is on that at schools. Okay. We're at the end of tonight's discussion. Here's something to finish with: I've seen a couple of discussions on Godel's theorem on #AynRand recently. People have come on the channel claiming, in essence, that logic is incapable of adequately dealing with reality. Godel said so. This is what Godel's theorem says: "Within any rigidly logical mathematical system there are propositions (or questions) that cannot be proved or disproved on the basis of the axioms within that system and that, therefore, it is uncertain that the basic axioms of arithmetic will not give rise to contradictions." What's the problem with that? Logic is nothing like that! Will: why not? If I understand it correctly, that would be like saying you can't prove gravity by just saying "A is A". Godel spoke of systems that were self-contained: disconnected from reality. Logic is based on facts/axioms of reality and as such, a proposition which is not provable is arbitrary and implies no contradiction. provable/disprovable. Will: You mean that his criterion of a logical statement was whatever could be put in the form of a "categorical proposition", with no reference to whether that statement was connected to reality? of a = for a Subetai, precisely. Okay, so what about the comment that the basic axioms of arithmetic could end up contradicting themselves? If you apply his argument to Logic, he's saying that because there are arbitrary statements, you can know nothing. They won't. I can say that. Okay. So what keeps logic non-contradictory is reality. There is nothing inherent in the methodology of logic that can create a non-contradictory system. He'd be saying contradictions exist metaphysically. Okay. So we had no argument on that. :( * :) * Wright turns the channel log off Session Close: Sat Oct 21 00:04:44 1995