Three astronauts are stranded on a world populated by a rational but war-like people. The leader decides
to give the astronauts a logic test to see if the human race is rational. The three astronauts are lined up
single file, facing the same direction. A single feather, taken at random from a collection of three blue
feathers and two white feathers, is placed on the helmet of each astronaut. No astronaut can see his own
feather. They may not look around or communicate with each other in any way. The alien leader says,
"If any of you can tell me what color feather you have on your helmet and explain why it must be that
color, we will set you free. If you guess wrong, or give the right answer without a good explanation of
how you arrived at that answer, we will deem the human race as being dangerous and irrational. We will
destroy you and then destroy your entire planet." After a very long silence, the astronaut in the front
raises his hand and gives the correct answer and a logical explanation. What did he say? Your answer
must include the color of the feather and the explanation of why it must be that color.