Re: Derivations

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.
.

Relevant Pages

  • Re: Derivations
    ... >> Whales breathe by lungs and wales are warm-blooded. ... >> If wales breathe by lungs, ...
    (sci.logic)
  • Re: Of whales, gills, and the nested hierarchy
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    (talk.origins)
  • Re: Derivations
    ... Whales breathe by lungs and wales are warm-blooded. ... then whales are not fish ... just symbolize the above into SL, ... The book we use is called "The Logic Book", very novel name, I know. ...
    (sci.logic)
  • Re: Puijila darwini: Another non-transitional fossil not found!
    ... How about the evolution of land mammals into whales? ... Microevolution too? ... Moron. ... Lungs were not derived from gills. ...
    (talk.origins)