When actualised in a concrete school, the official discourse of inclusion and equity often encounters a series of obstacles that research strives to identify and address under the imperative to eliminate them. Through the exploration of classroom episodes, teacher interviews and field notes from a German secondary school, we take failure not as a correctable obstacle but as a symptom of the ideology at work in current educational practices. Symptoms, as Žižek (after Lacan) suggested, cannot be eliminated but always (re)emerge since they concern the impossibility of official discourses actualising themselves. We thus argue for a research agenda that learns from failure instead of research concerned with the possible successes that might prospectively be brought into existence, if just the "right" theory was applied "correctly".