This is a generalisation of "The three sages"

On a hot summer day, n equally bright philosophers, tired from all that philosophising, were napping in an orchard. A prankster came by, and painted all of their faces black with charcoal.

When the philosophers woke up, they started laughing at the others... until they suddenly realised all of their faces must be black!

How did they come to that conclusion?

Suppose there were 5 philosophers, and only 4 of the faces were painted.  The non-painted philosopher would see everyone laughing, and all of a sudden would stop laughing, realizing he too had a painted face.  But he didn't.  So is it really a valid deduction?

Posted by Charlie on 2004-04-13 14:08:02