In the broad light of day mathematicians check their equations and their proofs, leaving no stone unturned in their search for rigour. But, at night, under the full moon, they dream, they float among the stars and wonder at the miracle of the heavens. They are inspired. Without dreams there is no art, no mathematics, no life.
Michael Atiyah (2014). “Michael Atiyah Collected Works: 2002-2013”, p.267, Oxford University Press, USA