Quote of the Day

Many people will tell you that an expert is someone who knows a great deal about his subject. To this I would object that no one can ever know very much about any subject. I would much prefer the following definition: an expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them.

—Werner Heisenberg, in Quantum Questions

Quote of the Day

[Werner Heisenberg and I] were on a walk and somehow began to talk about space. I had just read Weyl’s book Space, Time, and Matter, and under its influence was proud to declare that space was simply the field of linear operations. “Nonsense,” said Heisenberg. “Space is blue and birds fly through it.”

—Felix Bloch