Quantum Darwinism is a theory about how a quantum system can become a part of the everyday world around us. It suggests that in a quantum system, particles can "evolve" over time to become more stable and more likely to show up in everyday measurements. It's similar to the way that living things can evolve to become better adapted to their environment. It means that when you measure something in the quantum world, only the most stable particles will show up and the other particles will "fade away."