A Simple Logical Puzzle That Shows How Illogical People Are

Re:A Simple Logical Puzzle That Shows How Illogical People Are by ikeboy on Friday May 22, 2015 @04:44PM (#9590827)

>The problem with this is that the 5 card also needs to be turned; it might have an even number on the back.

If you can't be sure that the cards have a color and a numbers, there's nothing outlawing a 5-6 card, which breaks (2).

[ Parent | on HN ]

Re:A Simple Logical Puzzle That Shows How Illogical People Are by greggyb on Friday May 22, 2015 @04:56PM (#9590873)

So if I understand correctly:

You trust that if a card has a color on one side, it has a number on the other side.

You do not trust that if a card has a number on one side, it has a color on the other side.

Is this correct?

[ Parent | on HN ]

Re:A Simple Logical Puzzle That Shows How Illogical People Are by ikeboy on Friday May 22, 2015 @05:08PM (#9590906)

No. I don't make any assumptions as to anything I can't see.

However, regardless of what's on the back of blue, (2) will still be correct; the consequent is true, therefore the conditional is true.

[ Parent | on HN ]

Re:A Simple Logical Puzzle That Shows How Illogical People Are by greggyb on Friday May 22, 2015 @05:30PM (#9590979)

Okay, I see where you're coming from now.

(1) may or may not be true. Understanding that we cannot trust (1), but that we don't care to verify it, then the 5 is necessary to prove (2).

That is much more subtle than I originally interpreted from you original post. Thanks for your patient explanation.

[ Parent | on HN ]