This chapter takes a critical look at Jacques Lacan, the French psycho-analyst who has become a cultural icon. Lacan is an example of what can happen when a theorist puts ideas above the need for evidence and writes obscurely. This chapter examines in detail his famous mirror stage paper, showing that Lacan presents little evidence for his ideas and findings. He refers to the work of psychologists, such as Wolfgang Köhler, but his references do not match what the psychologists actually wrote or claimed to have found. Lacan, by contrast, does not cite the work of Henri Wallon, who outlined very similar ideas about mirror recognition before Lacan. It is suggested that the evidence does not support Lacan’s theory about the way children recognise themselves in the mirror. The example of Lacan is used to illustrate the need for evidence and the dangers of obscure writing.