Max Born · The probability rule
What is the wave function actually telling us?
That time, that place
In 1926 Schrödinger produced an equation for the electron's wave. It worked remarkably well.
But nobody knew what the wave was. Schrödinger himself thought the electron was a real cloud spread through space.
Why this question
There was a problem: detect an electron and it is always found at a point. It has never been found spread out.
Born's proposal: the wave is not the electron spread out. The square of its magnitude is the probability of finding the electron there.
In plain words, the wave function is not a picture of where the electron is but a table of how likely you are to meet it.
What was found
That one line fixed the character of quantum mechanics — and started an argument.
Einstein's remark about God not playing dice was a response to this reading. Schrödinger disliked it enough in his own equation to invent the cat.
Born's Nobel came in 1954, twenty-eight years after the proposal. Being Jewish, he had been driven out of Germany in 1933 and went to Britain.
Every quantum calculation today runs on this rule: semiconductor design, molecular simulation, and the readout of a quantum computer.
The equation worked and nobody knew what its solution meant
It matched the fact that a detected electron always appears at a point
Quantum mechanics became a theory of probability, and the argument began