A soldier was ordered to go and shave all the soldiers in his squad - and only those - who don't shave themselves.
After thinking it over for a while, he discovered a fundamental flaw in the command, which made it impossible for him to carry out the order. What might that be?
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
