A philosophy professor (giáo sư triết học) stood before his class with some
items on the table in front of him. When the class began, wordlessly he picked
up a very large and empty mayonnaise jar (hộp bơ lớn và rỗng) and proceeded to fill it with rocks,
about 2 inches in diameter.
He then asked the students if the jar was full. They
agreed that it was.
So the professor then picked up a box of pebbles (những viên sỏi) and
poured them into the jar. He shook the jar lightly. The pebbles, of course,
rolled into the open areas between the rocks.