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 -~----------~----~----~----~------~----~------~--~---
