(The lecture theater became very quiet with this turn of events.)
Student : Sir, you can have lots of heat, even more heat, superheat, mega heat, white heat, a little heat or no heat. But we don’t have anything called cold. We can hit 458 degrees below zero which is no heat, but we can’t go any further after that. There is no such thing as cold. Cold is only a word we use to describe the absence of heat. We cannot measure cold. Heat is energy. Cold is not the opposite of heat, sir, just the absence of it.
(There was pin-drop silence in the lecture theater.)
Student : What about darkness, Professor? Is there such a thing as darkness?
Professor: Yes. What is night if there isn’t darkness?