This paper introduces the Special Issue on 'post-truth'. The contributions to this special issue try between them to strike a right balance. To establish how new ‘post-truthism’ really is – or isn’t. To seek a point of reflection on whatever is new in our current socio-political straits. And to consider seriously how philosophy can help. Whether by wondering about the extent to which reason, or truth, may rightly, if one follows Wittgenstein, be viewed in certain respects as a constraint upon thought or opinion. Or indeed by wondering whether we still have a long way to go in approaching truth at all.