As always, thanks, Bruno for taking the time to educate this bum. Starting at the bottom: "To ask a logician the meaning of the signs, (...) is like asking the logician what is logic, and no two logicians can agree on the possible answer to that question." *This is why I asked -- YOUR -- version.* *** "Logic is also hard to explain to the layman,..." *I had a didactically gifted boss (1951) who said 'if you understand something to a sufficient depth, you can explain it to any avarage educated person'. * *And here comes my * *"counter-example" to your A&B parable: condition: I have $100 in my purse.* *'A' ** means "I take out $55 from my purse" and it is true. * *'B' means: I take out $65 from my purse - and this is also true. * *A&B is untrue (unless we forget about the meaning of & or and . In any language.* *** *"*I think you are pointing the finger on the real difficulty of logic for beginners...." *How else do I begin than a beginner? to learn signs without meaning, then later on develop the rules to make a meaning? My innate common sense refuses to learn anything without meaning. Rules, or not rules. I am just that kind of a revolutionist. * *Finally, (to begin with) * *..."*study of the laws of thought, although I would add probability theory to it ...???" *I discard probability as a count - consideration inside a limited (cut) model, 'count'* *- also callable: statistics, strictly limited to the given model-content of the counting - * *with a notion (developed in same model) "what, or how many the next simialr items MAY be" - for which there is no anticipation in the stated circumstances. To anticipate a probability one needs a lot of additional knowledge (and its critique) and it is still applicable only within the said limited model-content. * *Change the boundaries of the model, the content, the statistics and probability will change as well. Even the causality circumstances (so elusive in my views). * ** *Regards* *John*
** ** On Tue, May 19, 2009 at 11:51 AM, Bruno Marchal <[email protected]> wrote: > > Hi John, > > > On 18 May 2009, at 21:00, John Mikes wrote: > > > Bruno: > > > > could you tell in one sentence YOUR identification for logic? > > That is a difficult question, and to be honest, I am still searching. > As a platonist (that is: classical logician) I am OK with the idea > that logic is the abstract (domain independent) study of the laws of > thought, although I would add probability theory to it (like Boole). > > > > > (I can read the dictionaries, Wiki, etc.) > > I always say :common sense, but what I am referring to is > > -- -- M Y -- -- common sense, > > distorted - OK, interpreted - according to my genetic built, my > > experience (sum of memories), instinctive/emotional traits and all > > the rest ab out what we have no idea today yet. > > I can agree with this, althought the aim is too suppress as far as > possible the distortion. > > > > > > I never studied 'formal' logic, because I wanted to start on my own > > (online mostly) and ALL started using signs not even reproducible on > > keyboards > > That is why Knuth invented LATEX :) > > > > > and not explained what they are standing for. As I guessed: the > > 'professors' issued "notes" at the beginning of the college-courses > > (($$s?)) and THERE the students could learn the 'vocabulary' of > > those signs. > > You also use some of them. > > I think you are pointing the finger on the real difficulty of logic > for beginners. You are supposed not to attribute meaning on those > signs, because what the logician is searching for is rule of reasoning > which does not depend on the meaning. The hardness of logic is in the > understanding of what you have to NOT understand to proceed. Logicians > take the signs as just that: sign, without meaning. Then they will > develop rule of transformation of those sign, in such a way that > machine can play with them, and mathematical rule of meaning, and they > are happy when they succeed to find nice correspondence between rule > and meaning. It makes the subject both very concrete and abstract at > the same time. I am used to think that logic is the most difficult > branch of math. Somehow, computer science makes it more easy. It > motivates the point of not trying to put meaning where none is > supposed to be. > > > > > > > > I was looking at a dozen books as well and did not find those signes > > explained, not in footnotes, not in appendicis, not as intro- or > > post- chapters. They were just applied from page 1. > > So I gave up. > > I can understand. It is hard to study logic alone. Yet there are good > books, but it takes some effort to understand where you have to take > those sign literally. I would suggest the reading of the little > penguin book by Hodges "Logic", which is perhaps clear for an > introduction. > Logic is laso hard to explain to the layman, because it concerns > objects which look like formal things, and it takes time to understand > that we study those objects without interpreting them. beginners take > time to understand the use of saying that, for example, we will say > that "A & B" is true when A is true and B is true. They can believe > that they learn nothing here, but they are false because the "&" is > formal, and the "and" is informal. After all you do learn something if > I say that "A et B" is true when A is true and B is true. In this case > you learn french, which are at the same level of informality, but in > logic you attach rules and meaning to explicitly formal things on > which you reason *about*. > To ask a logician the meaning of the signs, is a bit like asking a > biologist the meaning of "ATTAGTTCAATCCCT" or DNA. It is like asking > the logician what is logic, and no two logicians can agree on the > possible answer to that question. When student ask some question > here, it is not rare the answer he get is just "we are not doing > philosophy here". The object study is far more concrete than beginners > can imagine, and that is why the notion of machine and computer > science can help a lot for many parts of logic. > > Bruno > > > http://iridia.ulb.ac.be/~marchal/ > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~----------~----~----~----~------~----~------~--~---
