Economic Imagination

Curvas de indiferença - F.Y.Edgeworth (1881)
Edgeworth - Mathematical Psychics (1881)

Every theory, Adam Smith teaches, is a way of imagining things. If there are systems which are preferable to others, it is in so far as they explain, with a refinement and elegance of means which the others lack, varied and complex phenomena, reducing them to a unified set of principles, and giving them the appearance of a regularity and constancy without which they would elude our understanding. This observation, which was made regarding astronomy, also applies to the then emerging science of economics.