Which perceptions are real, and which are not? The aural and/or visual hallucinations of patients with schizophrenia are deemed ‘unreal’, because they are experiences not shared by any of the people around them; but the same is, and has been, true of people who have had visions of the Virgin Mary, other saints, or – as in the case of the Romantic poet, William Blake – angels. Still others, including multiple witnesses at a time, have seen Unidentified Aerial Phenomena. Are these ‘anomalous experiences’, where sincerely believed in by those claiming to have had them, also ‘unreal’? What is ‘reality’? Would an ontology that accepted any or all such experiences as real be coherent and logically defensible?