Hans Vaihinger is known chiefly for the fictionalist outlook developed in his 1911 Philosophie des als ob (The Philosophy of As-If), a text that has resonated in the work of subsequent thinkers. Drawing partly on his intensive studies of Kant and partly on the influence of Schopenhauer and Nietzsche, Vaihinger holds that the human quest for truth is inherently deluded and a source of unnecessary intellectual pain and frustration. We should therefore renounce it, though not, like the sceptic, in a spirit of defeat but rather with a clear-headed fictionalist acceptance that we must carry on thinking and behaving as if certain truths existed and we were suitably placed to discover them.