Heron Suit
05-30-2015, 06:32 PM (This post was last modified: 05-30-2015 06:33 PM by Dave Britten.)
Post: #1
 Dave Britten Senior Member Posts: 1,960 Joined: Dec 2013
Heron Suit
This is from Professor Stewart's Cabinet of Mathematical Curiosities, a rather good book so far. Should make for good beach/camping reading

The logic on this one particular puzzle isn't adding up for me, though.

Quote:No cat that wears a heron suit is unsociable.
No cat without a tail will play with a gorilla.
Cats with whiskers always wear heron suits.
No sociable cat has blunt claws.
No cats have tails unless they have whiskers.
Therefore:
No cat with blunt claws will play with a gorilla.
Is the deduction logically correct?

I came up with yes, it is. But then I checked the answer in the back of the book. (Spoilers below.)

Quote:The deduction is incorrect. Consider a cat with blunt claws that plays with a gorilla, does not wear a heron suit, has a tail, has no whiskers, and is unsociable. The first five statements are all true, but the sixth is not.

Wait, huh?

Quote:No cats have tails unless they have whiskers.
Quote:...has a tail, has no whiskers...

Am I parsing that wrong, or do those two qualities contradict rule five? To me, that rule reads "tail -> whiskers".
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 Messages In This Thread Heron Suit - Dave Britten - 05-30-2015 06:32 PM RE: Heron Suit - Gerald H - 05-30-2015, 07:02 PM RE: Heron Suit - Dave Britten - 05-30-2015, 08:01 PM RE: Heron Suit - Gerald H - 05-31-2015, 07:19 AM RE: Heron Suit - Thomas Radtke - 05-31-2015, 10:35 AM RE: Heron Suit - Bill (Smithville NJ) - 05-31-2015, 12:21 PM RE: Heron Suit - Dave Britten - 05-31-2015, 05:21 PM RE: Heron Suit - Thomas Radtke - 06-01-2015, 05:12 AM RE: Heron Suit - Dave Britten - 06-01-2015, 11:03 AM RE: Heron Suit - EdS2 - 06-01-2015, 08:45 AM

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