Alas! Alas! Life is full of disappointments; as one reaches one ridge there is always another and a higher one beyond which blocks the view.

Never keep a line of retreat: it is a wretched invention.

The history of the human race is a continual struggle from darkness into light. It is, therefore, to no purpose to discuss the use of knowledge; man wants to know, and when he ceases to do so, is no longer a man.

Is it not in the struggle to obtain knowledge that happiness exists? I am very ignorant, consequently the conditions of happiness are mine.

It is better to go skiing and think of God, than go to church and think of sport.

Never stop because you are afraid - you are never so likely to be wrong.

I demolish my bridges behind me - then there is no choice but forward.