Shade makes colors loom and be thoughtful.
It has the afterlife atmosphere
but also the philosophic stone cool.

It is both day and night civilized,
the colour of reading, the tone
of inside, and of inside the mind.

--Les Murray, Rooms of the Sketch Garden

At a certain stage in the development of every science a degree of vagueness is what best consists with fertility.

--William James, The Principles of Psychology