Quantum rules, applied at a large scale, generate absurd paradoxes like a cat both alive and dead.
Schrödinger imagined a cat sealed in a box, linked to a random quantum event. By the strict rules, the cat would be, on paper, both alive and dead until you open the box. He did not actually believe this — he wanted to show how strange the theory gets at a large scale.
Schrödinger's cat was not a real experiment, but a demonstration of a logical problem. He wanted to show that quantum rules cannot describe large objects without becoming absurd. When you open the box, the cat is either alive or dead — not both. The problem is that theory says before you look, it is in both states. This is like saying an egg is simultaneously boiled and raw until you crack it. Schrödinger called this situation 'perplexing'. He suggested that our lack of knowledge is not the same as a real state of superposition.
Why it matters The paradox is still used today as a test for the limits of quantum computers.