The legal systems of non-Western peoples deserve special treatment. Some legal philosophers have argued that because folk and customary law, as non-Western legal systems are sometimes known, are (usually) oral, they represent ancient, unchanging law, as opposed to Western written law, which is new, a distinction lacking empirical foundation. An older term, primitive law, refers to the law of technologically primitive peoples. Some writers erroneously refer to U.S. federal law pertaining to aboriginal peoples as aboriginal law and indigenous law, but these terms should refer to these peoples' own law and institutional systems.