Life, Albert Einstein

Let us not forget that knowledge and skills alone cannot lead humanity to a happy and dignified life. ... I claim credit for nothing. Everything is determined, the beginning as well as the end, forces over which we have no control. It is determined for the insects as well as for the stars, Human beings, vegetables or cosmic dust, we all dance to a mysterious tune, intoned in the distance by an invisible piper.

- Albert Einstein (1879-1955)

Happiness, Aristotle

One swallow does not make a summer, neither does one fine day; similarly one day or brief time of happiness does not make a person entirely happy.

- Aristotle (384BC-322BC)