The Ur-language hypothesis is not, of course, inconsistent with linguistic nativism. However, if true, it does weaken any argument from the existence of universals to the innateness of linguistic knowledge. For if languages have a common ancestor, then it is possible to explain universals — even ones that seem strange from a functional point of view — as being the result of our ancestors' having adopted a certain solution to a linguistic coordination problem. Like driving on the right side