Non-overlapping magisteria

Non-overlapping magisteria simply means that two different things don't get mixed together. This is a concept that was first used by a scientist named Stephen Jay Gould, who believed that any questions of fact or questions about how the world works should be decided by science, and any questions about ethics and morality should be decided by religion or philosophy. So for example, science can show us what ingredients make up a cake, but it can't say whether it's okay to eat cake for breakfast. That part is for religion and philosophy to decide.