Copenhagen, 1926

The sun glared off the snow, shining the early November light into the room as if from a mirror.

Niels Bohr noticed when he walked into the light he felt noticeably warmer than when he walked into its shadow.

Werner Heisenberg stared outside the window without moving.

“You are taking it too hard,” Niels said.

Werner waved his hand in the air, the smoke from his cigarette making spiral figures. “Schrödinger’s ‘visualization is not quite right’—he is correct in that, certainly. His visualization is crap.”

“Werner,” said Niels gently. “He has shown his wave equation and your matrix mechanics are equivalent.”

“Crap.”

“Did you read Von Neumann’s paper?”

“Yes,” Werner said shortly.

“He shows that both sets of equations can be shown to be equivalent in Hilbert space. Is that crap?”

Werner remained silent for a moment. “There is a fundamental problem. A presumption that there is anything there at all until it is measured.”

“Yes. Even Erwin admits that.”

“Then, we cannot know that which cannot be measured!”

“Yes.” Niels thought for a moment. “But there is opportunity there.”

Werner looked away from the window. “What do you mean?”

“It is true that we cannot know that which cannot be measured,” said Niels casually. “But the corollary is also true: we can know that which can be measured.”

Werner looked blank. “Yes.”

“We can measure the speed of light to be a constant and the lensing of light in a gravitational field. Thereby, we can know relativity. We can measure the interference pattern of light and the activity of electrons. Therefore, we can know quantum mechanics.”

“We can’t know everything. Not everything can be measured.”

Niels nodded. “I know. But let us remain with those things that can be measured.”

“All right.”

“Quantum mechanics and relativity are two independent views of how the world behaves. How we observe the universe determines what we will observe.”

“Of course.”

“There is an apparent contradiction between quantum mechanics and relativity. I am not saying this contradiction will stand, but it does stand now. There could, therefore, be other views of world behavior equally rigorous and compelling but with equally strong apparent contradiction as there is between relativity and quantum mechanics. A verifiable observation contradicting both quantum mechanics and relativity would require its own different view of the universe.”

Werner stared at him. “What are you talking about?”

Niels paused for a moment and knocked the ash from his cigarette. “I must tell you about my mother.”