Have you heard that language is violence and that science is sexist? Or been told that being obese is healthy, that there is no such thing as biological sex, or that only white people can be racist? Helen Pluckrose and James Lindsay document the evolution of the dogma behind these ideas, from its origins in French postmodernism to its refinement within activist academic fields. Today this dogma is recognisable as much by its effects, such as cancel culture and social-media pile-ons, as by its assertions, which are all too often taken as read: knowledge is a social construct; science and reason are tools of oppression; all human interactions are sites of oppressive power play; and language is dangerous. As they warn, the unchecked proliferation of these beliefs present a threat to liberal democracy.