Derivations
in [Logic]
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From: 1st Semester Logic Student on 14 Jun 2005 16:38 "Do you know what 'SD' stands for? That might be a start. Thanks." Hey, yes, SD simply stands for "Sentential Logic: Derivations." More less I am given an argument, like: Whales breathe by lungs and wales are warm-blooded. If wales breathe by lungs, then whales are not fish --------------------------- Whales are warm-blooded and whales are not fish The top two being the premise and the bottom being the conclusion. I just symbolize the above into SL (sentential logic), which is pretty easy. The hard part is that after symbolizing the argument, I must show that the conclusion can be derived from the premises. The rules for doing so are on the website I mentioned earlier. The book we use is called "The Logic Book", very novel name, I know. Any more advice/questions would be great. I have the problems I mentioned in the OP done and will turn them in tomorrow afternoon. TY!
From: William Elliot on 14 Jun 2005 18:28 On Tue, 14 Jun 2005, 1st Semester Logic Student wrote: > "Do you know what 'SD' stands for? That might be a start. > > Hey, yes, SD simply stands for "Sentential Logic: Derivations." More > less I am given an argument, like: > Whales breathe by lungs and wales are warm-blooded. > If wales breathe by lungs, then whales are not fish > --------------------------- > Whales are warm-blooded and whales are not fish > Naw, they're fishy mammals. ;-) > The top two being the premise and the bottom being the conclusion. I > just symbolize the above into SL (sentential logic), which is pretty > easy. The hard part is that after symbolizing the argument, I must show > that the conclusion can be derived from the premises. The rules for > doing so are on the website I mentioned earlier. > Bah, as I told you, that website is not informative. Do you not listen? As you don't, I'll presume modus ponens. Then to symbolise the argument. A & B A -> ~C A & B premise A & B -> A theorem or rule of inference A modus ponens A -> ~C premise ~C modus ponens > The book we use is called "The Logic Book", very novel name, I know. > Any more advice/questions would be great. I have the problems I > mentioned in the OP done and will turn them in tomorrow afternoon. > I don't back track as it's too time comsuming and out of 10 math groups, the posts with best presentations are attended to first, the others take their chances. The Logic Book is weird, in a world of it's own with different terminology. The usual expression for SL is propositional calculus or perhaps propositional logic.
From: Ken Quirici on 14 Jun 2005 20:05 William Elliot wrote: > On Tue, 14 Jun 2005, 1st Semester Logic Student wrote: > > "Do you know what 'SD' stands for? That might be a start. > > > > Hey, yes, SD simply stands for "Sentential Logic: Derivations." More > > less I am given an argument, like: > > Whales breathe by lungs and wales are warm-blooded. > > If wales breathe by lungs, then whales are not fish > > --------------------------- > > Whales are warm-blooded and whales are not fish > > > Naw, they're fishy mammals. ;-) > > > The top two being the premise and the bottom being the conclusion. I > > just symbolize the above into SL (sentential logic), which is pretty > > easy. The hard part is that after symbolizing the argument, I must show > > that the conclusion can be derived from the premises. The rules for > > doing so are on the website I mentioned earlier. > > > Bah, as I told you, that website is not informative. > Do you not listen? As you don't, I'll presume modus ponens. > Then to symbolise the argument. > A & B > A -> ~C > > A & B premise > A & B -> A theorem or rule of inference > A modus ponens > A -> ~C premise > ~C modus ponens > > > The book we use is called "The Logic Book", very novel name, I know. > > Any more advice/questions would be great. I have the problems I > > mentioned in the OP done and will turn them in tomorrow afternoon. > > > I don't back track as it's too time comsuming and out of 10 math groups, > the posts with best presentations are attended to first, the others take > their chances. > > The Logic Book is weird, in a world of it's own with different > terminology. The usual expression for SL is propositional calculus > or perhaps propositional logic. Enderton uses SL but to stand for sentential logic. Thanks. Ken
From: Jim Spriggs on 14 Jun 2005 20:22 1st Semester Logic Student wrote: > > The book we use is called "The Logic Book", 556 pages
From: Sevenhundred Elves on 16 Jun 2005 14:22
1st Semester Logic Student wrote: > Hey guys! > > Here is a link to the rules of SD. I'm supprised you guys haven't heard > of it. It seems to be in every logic book I've seen although I know you > guys are more math based and this is a philosophy class; which I know > you hate. All the rules we use are found at this website. Although it > is not from my university, they are using the same rules we (our book) > uses. > > http://www.unc.edu/~theis/logic/SDrules.html > > Thanks! The rules are the standard ones, of course, but I had never seen that particular system of displaying or manipulating them before. However, I looked around a bit at the site and found a link to a program called Bertie3, which I downloaded. It was fun to play with, but I'm not sure I would have been able to figure out how to make "Sententional logic derivations" in that form if I weren't already acquainted with logic. You, on the other hand, have a whole book to help you figure it out, and a teacher whom you can ask, so I guess the program would be of tremendous help to you. Why not download it and play around with it for a while? S. |