“Life is doubt,And faith without doubt is nothing but death.”

“Only he who attempts the absurd is capable of achieving the impossible.”

“At times to be silent is to lie. You will win because you have enough brute force. But you will not convince. For to convince you need to persuade. And in order to persuade you would need what you ...”

“Those who believe that they believe in God, but without passion in their hearts, without anguish in mind, without uncertainty, without doubt, without an element of despair even in their consolation...”

“Faith which does not doubt is dead faith. -Miguel de Unamuno, philosopher and writer (1864-1936)”

“It is not usually our ideas that make us optimists or pessimists, but it is our optimism or pessimism that makes our ideas.”

“When man will return to nature, nature will return to him.”

“The sky is an enormous man.”

“When the full-grown poet came,Out spake pleased Nature (the round impassive globe, with all its shows of day and night,) saying, He is mine;But out spake too the Soul of man, proud, jealous and unr...”

“Yes, a war is inevitable. Firstly, there's you fellows who can't be trusted. And then there's the multitude who mean to have bathrooms and white enamel. Millions of them; all over the world. Not me...”

“Well-being is attained little by little, and nevertheless is no little thing itself.”

“Be not the first by whom the new is tried, Nor yet the last to lay the old aside, is a safe rule for those who would always retain the good opinion of that all-powerful, but somewhat unintelligent,...”

“I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettie...”

“To know the history of science is to recognize the mortality of any claim to universal truth. ”

“The scientist only imposes two things, namely truth and sincerity, imposes them upon himself and upon other scientists.”