Werner Heisenberg

"Freedom is the right to question and challenge authority, and to think and speak without fear of retaliation."

"The law of causality will be kept intact only as long as we cannot distinguish between the future and the past."

"Understanding nature means going beyond the phenomena to the underlying principles."

"The questions we pose determine the kind of answers we get."

"What is small is beautiful, and what is beautiful contains infinite depth."

"The poet and the scientist see the same world differently, but both see truth."

"Man is not the lord of all beings, but he is the interpreter of all being."

"Science progresses through revolutions in thought, not gradual accumulation."

"The observer and the observed are never separate."

"What we say about the atom is always somewhat relative to the way we describe it."

"Energy is not a substance; it is a concept which we define in order to understand nature."

"The relationship between the observer and the observed must be preserved."

"Great spirits have always encountered violent opposition from mediocre minds."

"Every word in our language is an expression of a reality perceived by human beings."

"The universe behaves as if it had a sense of humor."

"What lies behind us and what lies before us are tiny matters compared to what lies within us."

"A discovery is made not when a man finds something but when he realizes what he has found."

"The task of science is not to invent explanations for spiritual worlds, but to describe the natural world."

"What is most important cannot be measured, only understood."

"Language is not just a tool for describing the world; it creates the world we describe."

"The continuous world of our experience becomes a mosaic of atoms and forces."

"Every statement about nature involves an approximation."

"The smallest units of matter behave in ways that defy our everyday intuitions."

"What matters most is how we interpret the world, not what the world is in itself."

"The electron does not have as much concreteness as a grain of sand."

"Thinking is a very fundamental form of human experience."

"The principle of uncertainty is not a discovery but a requirement of our description."

"Nature is not revealed to us all at once; it unfolds through our questions."

"What we know is determined by how we ask the question."

"The world is not made of substance; it is made of possibilities."