There once was a man selling spears and shields.
About his spears he said, ‘They are so sharp they can pierce anything!’
About his shields he boasted, ‘My shields are so solid, nothing can dent them.’
Then a customer asked him, ‘What if I were to throw your spear at your shield?’
The seller could not respond.
CHINESE PHILOSOPHICAL STORY FROM THE HAN FEIZI, 3RD CENTURY B.C.
What happens when the irresistible force meets the immoveable object?