Contrary to widespread assumptions, post-truth politicians formally adopt a rhetoric of ‘truth’ but turn it against established experts. To explain one central factor behind this destructive strategy and its success with voters, I consider Walter Lippmann and Friedrich Hayek, who from 1922 onwards helped develop and popularize a political rhetoric of ‘truth’ in terms of scientific expertise. In Hayek’s influential version, market economics became the crucial expert field. Consequently, the 2008 financial crisis impacted attitudes towards experts more generally. But even sweeping rejection of experts continues to use the rhetoric, by now dominant, of expert truth. Paradoxically, this bipartisan language fuels division as opponents accuse each other of disregarding ‘truth itself’. Against the underlying metaphysics of context-free ‘facts’, John Dewey and Alfred Schutz recommend understanding truth as ‘presumptive’ knowledge produced within human practices, which can be robust but requires a readiness to engage in pluralistic and open-ended processes of (re-)contextualization.