"Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world. In our endeavour to understand reality we are somewhat like a man trying to understand the mechanism of a closed watch. He sees the face and the moving hands, even hears its ticking, but he has no way of opening the case. If he is ingenious he may form some picture of a mechanism which could be responsible for all the things he observes, but he may never be quite sure his picture is the only one which could explain his observations. He will never be able to compare his picture with the real mechanism and he cannot even imagine the possibility or the meaning of such a comparison. But he certainly believes that, as his knowledge increases, his picture of reality will become simpler and simpler and will explain a wider and wider range of his sensuous impressions. He may also believe in the existence of the ideal limit of knowledge and that it is approached by the human mind. He may call this ideal limit the objective truth" (Einstein, The Evolution of Physics, 1938, CUP Archive, 1971, pp.31).
"Great spirits have always encountered violent opposition from mediocre minds. The mediocre mind is incapable of understanding the man who refuses to bow blindly to conventional prejudices and chooses instead to express his opinions courageously and honestly" (Einstein, Letter to philosopher Morris Raphael Cohen, 1940).
"science can only be created by those who are thoroughly imbued with the aspiration toward truth and understanding. This source of feeling, however, springs from the sphere of religion. To this there also belongs the faith in the possibility that the regulations valid for the world of existence are rational, that is, comprehensible to reason. I cannot conceive of a genuine scientist without that profound faith" (Einstein, Science and Religion, Conference on Science, Philosophy and Religion in Their Relation to the Democratic Way of Life, Inc., 1941).
"Science not only purifies the religious impulse of the dross of its anthropomorphism but also contributes to a religious spiritualisation of our understanding of life" (Einstein, Science and Religion, Conference on Science, Philosophy and Religion in Their Relation to the Democratic Way of Life, Inc., 1941).
"The further the spiritual evolution of mankind advances, the more certain it seems to me that the path to genuine religiosity does not lie through the fear of life, and the fear of death, and blind faith, but through striving after rational knowledge" (Einstein, Science and Religion, Conference on Science, Philosophy and Religion in Their Relation to the Democratic Way of Life, Inc., 1941).
"So many people today - and even professional scientists - seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is - in my opinion - the mark of distinction between a mere artisan or specialist and a real seeker after truth" (Einstein, Letter to physicist Robert A. Thorton, 1944).
"For the most part we humans live with the false impression of security and a feeling of being at home in a seemingly familiar and trustworthy physical and human environment. But when the expected course of everyday life is interrupted, we realise that we are like shipwrecked people trying to keep their balance on a miserable plank in the open sea, having forgotten where they came from and not knowing whither they are drifting. But once we fully accept this, life becomes easier and there is no longer any disappointment" (Einstein, Letter to a doctor and his wife who had lost a child or grandchild, they had been active in helping refugees from Nazi Germany, 1945).
"I live in that solitude which is painful in youth, but delicious in the years of maturity" (Einstein, Out of My Later Years, 1950, pp.5).
"A human being is a part of the whole, called by us 'Universe', a part limited in time and space. He experiences himself, his thoughts and feelings as something separated from the rest - a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security" (Einstein, 1950, printed in The New York Times, 29 March 1972).
"I have no special talents. I am only passionately curious" (Einstein, Letter to biographer Carl Seelig, 1952).
"The word god is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honourable, but still primitive legends which are nevertheless pretty childish. No interpretation no matter how subtle can (for me) change this" (Einstein, Letter to philosopher Eric Gutkind, 1954).
"People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion" (Einstein, Letter to the family of his lifelong friend Michele Besso, after learning of his death, 1955).
"The important thing is not to stop questioning; curiosity has its own reason for existing. One cannot help but be in awe when contemplating the mysteries of eternity, of life, of the marvellous structure of reality. It is enough if one tries merely to comprehend a little of the mystery every day. The important thing is not to stop questioning; never lose a holy curiosity" (Einstein, Statement to William Miller quoted in LIFE magazine, 2nd May 1955).
"Try to become not a man of success, but try rather to become a man of value" (Einstein, LIFE magazine, 2nd May 1955).
"An equation is something for eternity" (Einstein, quoted in Helle Zeit, Dunkle Zeit: In Memoriam Albert Einstein, 1956).