"" (the empty string), and
Anything else evaluates to
Michel Foucault says that there is not true about knowlege in the life, it is building with the time and the role that people play about certain object. So with the history is building the knowlege until for the last generation a knowlege is teached as the true thing. In progamming first you have to know that certains value return true not because its a true indepent of human knowlege just because many people say hey , these is going to be truee so like Foucault says Knowlege is builded.