The thirst after happiness is never extinguished in the heart of man. - Jean-Jacques Rousseau

Everything on earth is in continuous flux: nothing preserves a constant fixed form, and our affections towards external things pass and change with them... There is nothing solid to which the heart can attach itself. Also, there is scarcely a pleasure here below which does not pass; as for enduring happiness, I doubt that it can be known. In our most vivid joys there is scarcely an instant at which our hearts could truly say: would that this moment might last forever; and how can one call that transient state happy which still leaves our hearts disturbed and empty, which makes us regret something beforehand or still desire something afterwards.

Everything fluctuates on earth; nothing remains in a constant and lasting form, and those affections which are attached to external things necessarily change with their object. We are ever looking forward or backward, ruminating on what is past, and can return no more, or anticipating the future, which may never arrive; there is nothing solid to which the heart can attach, itself, neither have we here below any pleasures that are lasting. Permanent, happiness is, I fear, unknown, and scarcely is there an instant in our most lively enjoyments when the heart can truly say, May this moment last forever!!! How then can such a fugitive state be called happiness, which leaves an uneasy void in the heart, which ever prompts us to regret something that is past, or desire something for the future?

Der wirklich freie Mensch will nur, was er vermag, und tut nur, was ihm gefällt.