Niels Bohr

"It is the tension between creativity and skepticism that has produced the stunning and unexpected findings of science."

"There are trivial truths and great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also a great truth."

"I must say I like long and elegant mathematical arguments at the expense of any appeal to experiment and experience."

"Physics is to be regarded not so much as the study of something a priori given, i.e. something independent of how we act, but rather as the science of the description of nature by the help of our concepts."

"The problems that exist in the world today cannot be solved by the level of thinking that created them."

"Just as in a theatrical play one is moved by fictitious joys and sorrows, so too in actual life one is concerned with fictions."

"A physicist is just an atom's way of looking at itself."

"The greatest strength of the scientist is to know what he does not know."

"Niels Bohr used to say that the task of science is not to discover the real essence of things, but simply to describe their relations."

"The first principle is that you must not fool yourself, and you are the easiest person to fool."

"In the old days, one had the idea that if all the atoms were knocked apart, great new sources of energy would be released, as from a coiled spring."

"Light and matter are both single entities, and the apparent duality arises in the limitations of our language."

"An independent reality in the physical sense is an unwarranted causality."

"You are not thinking, you are just being logical."

"The beauty of science is that it can be wrong, and we all know how to fix it."

"One can hardly overstate the importance of the careful design of experiments, though good luck can sometimes serve as well."

"In physics, we have learned that nothing is permanent, everything is subject to change."

"What we observe is not nature in itself but the nature exposed to our method of questioning."

"The task of the scientist is to identify which questions are meaningful and which are not."

"We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough."

"The development of quantum mechanics has convinced me that the old causal philosophy is dead."

"Science is not a collection of laws, but a method for making observations and predictions."

"Those who say it cannot be done should get out of the way of those doing it."

"Reality is merely an illusion, albeit a very persistent one."

"The correspondence principle states that a new scientific theory should reduce to the old one in the appropriate limit."

"We are all passengers on Spaceship Earth, and we must work together."

"In the atomic world we have discovered that nature behaves in a manner that is completely contrary to our intuition."

"The knowledge of nature cannot be built up without constant interaction between experiment and theory."

"I recognize the importance of the past, but I believe that those who are governed by the future are the true builders of society."

"The history of science is a history of increasingly sophisticated questions asked of nature."