It is the color closest to light. In its utmost purity it always implies the nature of brightness and has a cheerful, serene, gently stimulating character. Hence, experience teaches us that yellow makes a thoroughly warm and comforting impression.

Man is not born to solve the problem of the universe, but to find out what he has to do; and to restrain himself within the limits of his comprehension.

Every man has enough power left to carry out that of which he is convinced.

The sum which two married people owe to one another defies calculation. It is an infinite debt, which can only be discharged through all eternity.

Science arose from poetry... when times change the two can meet again on a higher level as friends.

When I consider the narrow limits within which our active and inquiring faculties are confined; when I see how all our energies are wasted in providing for mere necessities, which again have no further end than to prolong a wretched existence; and then that all our satisfaction concerning certain subjects of investigation ends in nothing better than a passive resignation... when I consider all this... I am silent.

To me the external existence of my soul is proved from my idea of activity. If I work incessantly until my death, nature will give me another form of existence when the present can no longer sustain my spirit.