It's not a historical article tracing the lineage of the feature. Ruby took some things the designer liked from Lisp, from Smalltalk, from Perl, from other pla

It's not a historical article tracing the lineage of the feature. Ruby took some things the designer liked from Lisp, from Smalltalk, from Perl, from other places. He liked symbols because they're good for performance (and compile-time correctness) at a low cognitive cost, and that's why Ruby has symbols.