An expert is a man who has made all the mistakes which can be made, in a narrow field.
Nothing exists until it is measured.
Every valuable human being must be a radical and a rebel, for what he must aim at is to make things better than they are.
If you aren't confused by quantum mechanics, you haven't really understood it.
Truth is something that we can attempt to doubt, and then perhaps, after much exertion, discover that part of the doubt is not justified.
When asked ... [about] an underlying quantum world, Bohr would answer, 'There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about Nature.'