> [!abstract] > "*Colorless green ideas sleep furiously*" was composed by Noam Chomsky in his 1957 book *Syntactic Structures* as an example of a sentence that is grammatically well-formed, but semantically nonsensical. [...] There is no obvious understandable meaning that can be derived from it, which demonstrates the distinction between syntax and semantics, and the idea that a syntactically well-formed sentence is not guaranteed to also be semantically well-formed. (Wikipedia, 2025). > [!note] > This is important to illustrate how the syntax (first order) and semantics (second order) are related but also operate independently, and it is entirely possible that one is valid but not the other. >[!related] >- **North** (upstream): [[Category mistake]]; [[First-order logic]] >- **West** (similar): — >- **East** (different): — >- **South** (downstream): —