Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or thought of the course of nature; beyond this he neither knows anything nor can do anything.
We have arranged for ourselves a world in which we can live - by positing bodies, lines, planes, causes and effects, motion and rest, form and content; without these articles of faith nobody could now endure life. But that does not prove them. Life is no argument. The conditions of life might include error.
When I behold a rich landscape, it is less to my purpose to recite correctly the order and superposition of the strata, than to know why all thought of multitude is lost in a tranquil sense of unity.
When ignorant people see someone who is dead, they are disgusted and horrified, even thought they too will be dead some day. I thought to myself: I don't want to be like the ignorant people. After then, I couldn't feel the usual intoxication with life anymore.
True science investigates and brings to human perception such truths and such knowledge as the people of a given time and society consider most important. Art transmits these truths from the region of perception to the region of emotion.
Nobody knows how the stand of our knowledge about the atom would be without him. Personally, [Niels] Bohr is one of the amiable colleagues I have met. He utters his opinions like one perpetually groping and never like one who believes himself to be in possession of the truth.