Schrodinger’s Cat is a well known thought experiment, where a cat that is trapped in a box has a 50% of surviving poison gas. Before opening the box, the cat is 50% alive and 50% dead. Schrodinger himself might never have actually came up with this thought experiment, instead gaining fame through Schrodinger’s wave function, which shows the probability of finding a particle in a given position.
This thought experiment is a result of matter being both waves and particles, called superposition. Superposition states that before observing something, it can be in multiple states at the same time. This is why Schrodinger’s main contribution to quantum mechanics, his wave function, describes everything in probabilities. Anything is just a blur of probability before it is measured.
For more info:
- TED Ed Video: https://www.youtube.com/watch?v=UjaAxUO6-Uw
- Superpostion: https://quantumatlas.umd.edu/entry/superposition