An engineer, a mathematician, and a physicist were asked to name the greatest invention of all times.
The engineer chose fire, which gave humanity power over matter.
The mathematician chose the wheel, which gave humanity the power over space.
The physicist mystic chose the thermos bottle.
“Why a thermos bottle?” the others asked.
“Because the thermos keeps hot liquids hot in winter and cold liquids cold in summer.
”“Yes — so what?”
“Think about it.” said the mystic reverently. That little bottle — how does little bottle knows when it’s summer and when it’s winter?