I missed this earlier this week: physicist John Wheeler has died at the age of 96. A snippet from the NY Times obituary:
At the same time, he returned to the questions that had animated Einstein and Bohr, about the nature of reality as revealed by the strange laws of quantum mechanics. The cornerstone of that revolution was the uncertainty principle, propounded by Werner Heisenberg in 1927, which seemed to put fundamental limits on what could be known about nature, declaring, for example, that it was impossible, even in theory, to know both the velocity and the position of a subatomic particle. Knowing one destroyed the ability to measure the other. As a result, until observed, subatomic particles and events existed in a sort of cloud of possibility that Dr. Wheeler sometimes referred to as “a smoky dragon.”
This kind of thinking frustrated Einstein, who once asked Dr. Wheeler if the Moon was still there when nobody looked at it.
Wheeler recognized that physics is about ideas and the language used to express those ideas, not just mathematics and experimentation. He coined and popularized several phrases during his long career, including black hole, wormhole, and quantum foam.