Heron Suit

[Dave Britten]

(05-31-2015 12:21 PM)Bill (Smithville NJ) Wrote:  Hi Dave,

This brings back memories of my senior year in college where I took a Philosophy course in Logic. It was sort of half Philosophy and half mathematics. I can remember taking similar word logic problems and converting them to 1 and 0 in logic tables and then solving for whether the conclusion was correct based on the mathematics of the logic table.

Unfortunately, I do not really remember how we set up the logic tables from the word problem. Been too long ago.

Bill
Smithville, NJ

That's basically what I did, recalling the Boolean logic we did in discrete math back in college.

You can express the rules thusly (using my interpretation for rule 5):

Quote:heron suit -> sociable
not(tail) -> not(play with a gorilla)
whiskers -> heron suit
sociable -> not(blunt claws)
tail -> whiskers

blunt claws -> not(play with a gorilla)

Then it's a matter of making transitive associations from "blunt claws" to "not(play with a gorilla)", using contrapositives where necessary (which is nearly every step).

Quote:blunt claws -> not(sociable)
not(sociable) -> not(heron suit)
not(heron suit) -> not(whiskers)
not(whiskers) -> not(tail)
not(tail) -> not(play with a gorilla)

But he's claiming "tail and not(whiskers)" is valid, which would contradict how I'm interpreting rule 5 (tail -> whiskers).

Reading it again (and again, and again, and again), it seems like it might be possible to interpret it as "The situation in which a cat has a tail unless it has whiskers does not arise", or alternatively, "Having whiskers does not necessitate the lack of a tail".

If that's how it's meant to be understood, then that rule actually doesn't reveal any relationship between tail and whiskers, and thus the deduction would be incorrect.

Time to go dig out that old discrete math textbook and see if I've forgotten some important detail about Boolean logic.