Schrodinger's Cat Was a Thought Experiment Against Quantum Theory

The image of a cat being both alive and dead in a box is a famous illustration of quantum weirdness, yet its creator meant it as a sharp criticism. In 1935, Austrian physicist Erwin Schrödinger was in a heated debate with his colleagues over the dominant interpretation of quantum mechanics. He was particularly bothered by the concept of superposition, which suggests a particle can exist in multiple states at once until it's measured. To show how nonsensical he believed this was when applied to the real world, he imagined a scenario where a cat's fate was tied to the quantum state of a single radioactive atom.

Schrödinger's thought experiment was a direct challenge to the so-called Copenhagen interpretation, championed by physicists like Niels Bohr. The setup—with the atom, a Geiger counter, a hammer, and a vial of poison—was designed to force a microscopic quantum event to have a direct, large-scale consequence. His point was to ask: at what exact moment does the system stop being a blurry superposition and become one definite reality? Does the cat count as an observer? Does the whole box remain in a state of suspended animation until a human opens it? By presenting this seemingly absurd outcome, Schrödinger argued that quantum theory must be incomplete, as it failed to provide a common-sense description of reality. Ironically, his memorable paradox is now the most famous example of the very concept he was trying to disprove.