Quotation

Imagine a cat, a vial of poison, and a radioactive source in a sealed box. If an internal sensor registers radioactivity, like an atom decaying, the vial is broken, releasing a poison that kills the cat. The atom has an equal chance of decaying or not decaying. It’s an ingenious way of linking an outcome in the classical world, our world, to a quantum-level event. The Copenhagen interpretation of quantum mechanics suggests a crazy thing: before the box is opened, before observation occurs, the atom exists in superposition—an undetermined state of both decaying and not decaying. Which means, in turn, that the cat is both alive and dead. And only when the box is opened, and an observation made, does the wave function collapse into one of two states. In other words, we only see one of the possible outcomes. For instance, a dead cat. And that becomes our reality.