Or Why Effective Theories are so … Effective
Solids, liquids, gases. What do these words really mean? How about cell, organ, or human? At a fundamental level, these things are complex assemblages of interacting subatomic particles. But you probably have an easy time recognizing a human without knowing about their electron configurations; you might instead identify key characteristics like physical appearance or behavior. These various abstractions help us understand the macro-world, but a seemingly naive philosophical question is “why can we do that?” Continue reading