Twin Earth thought experiment

The Twin Earth thought experiment, proposed by philosopher Hilary Putnam, explores the nature of meaning and reference in language. Imagine a planet identical to Earth, called Twin Earth, where a substance called "water" is actually a different chemical (XYZ), despite looking and behaving like water. On Earth, "water" refers to H2O, while on Twin Earth, "water" refers to XYZ. This experiment highlights that meaning depends on the context and environment, showing that language can refer to different things in different worlds, challenging our understanding of how words relate to the objects they describe.