The bubble logic driving tulipomania has since acquired a name: “the greater fool theory.” Although by any conventional measure it is folly to pay thousands for a tulip bulb (or for that matter an Internet stock), as long as there is an even greater fool out there willing to pay even more, doing so is the most logical thing in the world.
Michael Pollan, The Botany of Desire: A Plant's-Eye View of the World
economics, greater-fool-theory, logic, tulipomania, tulips