John Wheeler

"Quantum mechanics makes absolutely no sense."

"It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that quantum theory is so counter-intuitive that if you haven't been profoundly shocked by it, you haven't understood it."

"Time is what prevents everything from happening at once."

"The universe is a self-synthesizing machine."

"No phenomenon is a phenomenon until it is a registered phenomenon."

"We are not just mapmakers of nature. We are participants in it."

"The universe does not exist 'out there' independent of us. We are inescapably involved in bringing about that which appears to be happening."

"Information is the stuff of which reality is made."

"We live on an island of knowledge surrounded by a sea of ignorance."

"Behind it all is surely an idea so simple, so beautiful, that when we finally grasp it we will say to each other, how could it have been otherwise?"

"Nature isn't classical, dammit, if you want to make a simulation of nature, you'd better make it quantum mechanical."

"The most exciting phrase to hear in science is not Eureka but That's funny."

"Physics is really nothing more than a search for ultimate simplicity."

"One cannot be deeply responsive to the world without being saddened very often."

"Do not be afraid of making mistakes or taking risks."

"The best communication of ideas is through teaching."

"Ignorance is no excuse."

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

"How could the photon be a quantum particle?"

"The quantum principle is like a Kantian synthetic a priori principle."

"To understand is to know what to do."

"Peace comes from understanding, not ignorance."

"We are made of star stuff."

"The universe is not hostile, nor yet is it friendly. It is simply indifferent."

"Symmetry is a vast subject, significant in art and nature."

"Beauty is the first test; there is no permanent place in the world for ugly mathematics."

"The real problem of humanity is that we have Paleolithic emotions in a super-technological world."

"You have to recognize that great scientists are artists."

"Change is the only constant in the universe."

"The eye cannot see itself unless assisted by a mirror."