Hence it is clear that the space of physics is not, in the last analysis, anything given in nature or independent of human thought.

Albert Einstein, Nobel Prize Winner

Everything we call real is made of things that cannot be regarded as real.

Niels Bohr

Science cannot solve the ultimate mystery of nature. And that is because, in the last analysis, we ourselves are part of nature and therefore part of the mystery that we are trying to solve.

Max Planck. Nobel Prize Winner

I shall suppose that some malicious, powerful, cunning demon has done all he can to deceive me. I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely dreams that the demon has contrived as traps for my judgment.

Rene Descartes, 1639

If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet.

Niels Bohr, Nobel Prize Winner

Once upon a time, I, Chuang Chou, dreamt I was a butterfly, fluttering hither and thither, a veritable butterfly, enjoying itself to the full of its bent, and not knowing it was Chuang Chou. Suddenly I awoke, and came to myself, the veritable Chuang Chou. Now I do not know whether it was then I dreamt I was a butterfly, or whether I am now a butterfly dreaming I am a man.

From the writings of Zhuangzi, 369 BCE - 286 BCE