Goya's ‘The Dream of Reason brings forth Monsters’ was originally sketched in 1797 and forms part of the Capriccio cycle of engravings, first published in 1799. The cycle was conceived as a denunciation of human error and viciousness, and motivated by enthusiastic support for the enlightened ideals of the French Revolution. The individual works in the series are characterised by a contrast between light and shade, reason and madness, enlightenment and reaction, freedom and servitude. Goya added a short comment to this aquatint version: ‘Imagination deserted by reason creates impossible, useless thoughts. United with reason, imagination is the mother of all art and the source of all its beauty.’ Reason, left to work alone, creates monsters; while imagination unalloyed by the power of reason gives rise to futile ideas. This fundamental dialectic lies at the heart of the Enlightenment; and it remains with us today, embedded in our elementary thoughts and argument.

Wilhelm Hennis brought my attention to Goya's engraving after reading an earlier version of Chapter 6, prompted by Neurath's conception of economic organisation based upon natural calculation. As I argue in that chapter, Neurath's vision is of a rationalistic, transparent world in which human need and the goods required for its satisfaction can be calculated in natura, without the intervention of monetary forms of calculation which, by virtue of their abstraction, conceal the material nature of choices made.