I present to you a deck of 4 cards. Each card has on one side a letter of the alphabet, and on the other side a single digit from 0-9.

I propose a hypothesis that may apply to this deck:
If the letter is 'E', then the number on the other side is '4'.

I then drop the 4 cards on the table, and you see: 'B', '7', 'E', '4' (on the respective cards).

Which of the 4 cards must you turn over to verify or disprove my hypothesis?

(In reply to I don't understand by Dainma Felpry)

It makes sense if you think of a more mundane example.

If you said "All Irishmen have red hair", I could prove or disprove that by going through the entire world, going up to everyone I know to be an Irishman and asking him to remove his hat so I can see if his hair is red (that's like turning the E card over), and by going up to every person whose hair is obviously non-red and asking him if he's an Irishman (that's turning the 7 over). If I find one Irishman with non-red hair, or one person with non-red hair who is an Irishman, I have disproved the hypothesis. If I can't find anybody like that, the hypothesis is proved.  (Finding a red-haired German or a blonde Italian won't prove anything).

 

Edited on December 17, 2004, 2:38 am

Posted by Penny on 2004-12-17 02:13:45