Time to give Keats a go:

Beauty is truth and truth beauty. ( From Ode to a Grecian Urn)

Short, sweet and says it all really.

rede -That Hamlet quote is a favourite if mine too, and the sad Macbeth one;

Tomorrow, and tomorrow, and tomorrow,
Creeps in this petty pace from day to day,
To the last syllable of recorded time,
And all our yesterdays have lighted fools
The way to dusty death.

Space , time, and causality (or lack of it!) there.