Schrodingers cat. Artwork showing a cat both dead and alive inside a blue box. A quantum event (such as the decay of a radioactive particle) will trigger an event that will kill the cat, but because the box is sealed it is not known whether the quantum event has taken place or not. In this hypothetical situation, the cat is thought to be both alive and dead until observed. This is because according to quantum physics, a quantum event exists in an intermediate probabilistic state until it is observed. This thought experiment was devised in 1935 by the Austrian physicist Erwin Schrodinger (18871961).