In this chapter, a different expression of the notion of the double is introduced and discussed. Here, there is no apparent distinct double but rather there is an implicit assumption that doubles can and do exist. This implicit notion forms the basis for the abnormal belief in Capgras syndrome. Ray Bradbury’s ‘The Martian’, Patrick McGrath’s Spider, and Nabokov’s Despair are the prime examples of this approach to the notion of the double.

Doppelgänger is a term drawn from the writing of Jean Paul Richter in his novel Siebenkäs. This term is examined and discussed in this chapter. It stands for the possibility of the existence of a double of a living person and therefore raises questions about the nature of the self and of mind too. The concepts of self and mind are explored and the implications for philosophy of mind are examined. The importance of attending to the empirical literature rather than using thought experiments is emphasized.

In this chapter, I turn to how the abnormal experience of the double is manifest in the clinic. I give detailed descriptions of autoscopy and related conditions, namely autoscopic hallucination, heautoscopy, sense of presence, and negative autoscopy. Furthermore, I discuss dissociative identity disorder, and delusional misidentification syndromes. In all these abnormal phenomena, I draw on the classical case descriptions to illustrate how these conditions are experienced.

James Hogg’s The Private Memoirs and Confessions of a Justified Sinner sets the scene for the modern expression of the notion of the double in fiction. E. T. A. Hoffman’s novel The Devil’s Elixir covers a similar territory. In this chapter, these two novels provide the backdrop for an exploration of Dostoyevsky’s The Double. This is perhaps the most popular novel that deals with the concept of the double. I argue that the accuracy of the subjective experience of the double suggests that the authors probably had personal experience in autoscopy. This is particularly true of Guy de Maupassant in his novella The Horla. In these novels, the double has a physical existence independent of the originating self. This is true too for the novels by José Saramago and Shusaku Endo that deal with this subject.

Notions of the double have a long antiquity. The expression of the concept of the double in Euripides’s The Women of Troy is discussed as is the expression of the double in Plautus’s Amphitryon and The Brothers Menaechmus. The treatment of the double in the Epic of Gilgamesh and in the stories of Loki, the Norse god, is also explored.

In this chapter, I examine fictional and real-life examples of the double, in which there is no identifiable independent other. Robert Louis Stevenson’s The Strange Case of Dr Jekyll and Mr Hyde is the principal example of this approach. It provides the basis for discussing the real-life examples of Deacon Brodie and William Sharp. Here, the complexity of personality and the possibility of distinct but contradictory aspects of personality are examined.

This final chapter returns to the issues that the cognitive neuroscience of autoscopy raise for the philosophy of mind. The neuroscience project is to develop a detailed understanding and explanation of the relation between the physical and mental. I appeal to the works of Paul Schilder, Antonio Damasio, and Mohed Constandi to forge a tentative way of understanding how multiple perceptual modalities such as proprioception, vision, touch, and somatic perception are integrated to form a unified sense of the self and the body.

The focus of this chapter is how the material body is represented in the brain. The aim is to demonstrate the neural mechanisms underpinning body representation in order to show how the sense of self is experienced as embodied. Furthermore, given the underlying mechanisms underpinning the integration of self and body, how to understand the possibility of a separation of self and body as seen in autoscopy. I rely on the experiments of Olaf Blanke and his group in this regard.

Cinema has a long tradition of exploiting the notion of the double. This is because of the cinematic resources that are available to convincingly portray, visually, a doppelgänger. Alfred Hitchcock was the master of this form. In several films including Shadow of a Doubt, Strangers on a Train, The Wrong Man, Vertigo, and Psycho, Hitchcock established himself as the master of horror and exploited several different manifestations of the double. Other films dealing with the double, including The Matrix, Solaris, and Avatar, are also discussed.