The consciousness of the ...

The consciousness of the falsity of present pleasures, and the ignorance of the vanity of absent pleasures, cause inconstancy.
The consciousness of the falsity of present pleasures, and the ignorance of the vanity of absent pleasures, cause inconstancy.

Quotes from the same author

We are all something, but none of us are everything.
The heart has its reasons which reason knows not of.
Imagination disposes of everything; it creates beauty, justice, and happiness, which are everything in this world.
Man is equally incapable of seeing the nothingness from which he emerges and the infinity in which he is engulfed.
The least movement is of importance to all nature. The entire ocean is affected by a pebble.