There is an explanation of this by Janet Radcliffe Richards (<a href="http://en.wikipedia.org/wiki/Janet_Radcliffe_Richards" rel="nofollow">http://en.wikipedia.org/wiki/Janet_Radcliffe_Richards</a>) on a Philosophy Bites podcast, here it is: (<a href="http://www.philosophybites.libsyn.com/index.php?post_id=325536" rel="nofollow">http://www.philosophybites.libsyn.com/index.php?post_id=3255...</a>). Philosophy Bites are short (under 20 minute) interviews with contemporary philosophers.