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Sosia, a Greek slave from Thebes, returns home from war with his master Amphitryo. At the front door to his house he meets his exact double. It’s the god Mercury and he’s taken on Sosia’s perfect likeness. Mercury, through persuasion and aggression, manages to convince Sosia that he’s not, well, not himself. It’s Mercury who is. He’s the real Sosia. Sosia the slave gives in and reluctantly agrees with the god.
Jupiter, the king of the gods, wants to sleep with Alcmene, the loyal wife of Amphitryo. Jupiter reckons that the only way to do this is to become Amphitryo’s double. It works and that’s why he has Mercury on guard by the front door. This is to stop Amphitryo blundering in on the act. Amphitryo eventually does meet his double, Jupiter, and he’s as flummoxed as Sosia. But he doesn’t give in as easily as the slave. His innocent wife Alcmene has slept with Jupiter by then and she never gets the chance to say, “you are not the man I married”. Amphitryo was very jealous. But then how can you be jealous of “yourself”?
When the French psychiatrists Joseph Capgras (1873-1950) and Jean Reboul-Lachaux encountered the 53-year-old “Madame M” in the 1920s, she was seeing doubles all over the place. She thought that her husband, her children, and her neighbors — and even herself — had been replaced by exact "doubles". It was all part of a jealous ploy to purloin her property. Madame M was in Sosia’s predicament.
So it was to the legend of Amphitryo, Alcmene, and Sosia that Joseph Capgras and Jean Reboul-Lachaux turned. They must have known Plautus’ first version in Latin (dating from some time after 200 BCE) as well as Jean-Baptiste Molière’s 1668 version. They named Madame M’s illness after poor Sosia and in 1923 the illness became “l’illusion des sosies” (“the illusion of the Sosias”). These days the psychological problem takes its name from the lead author of the study. Now it’s called Capgras Syndrome, or, sometimes, delusional misidentification syndrome, or even the syndrome of subjective doubles.
What causes Capgras Syndrome? For the psychoanalysts, especially perhaps Anna Freud, it seems to have involved a jealous guilt, or even guilt over jealousy. To assuage this you create a double. Then you reject the double as an imposter and let yourself off the jealous or guilty hook — subconsciously — because the double is not the real person giving you the grief.
More recently work has focused, not on the mind, but on the brain. Chris Fiacconi, from the University of Western Ontario looked at what happens when people believe that someone they’re close to — usually a spouse — has been replaced by a double. Fiacconi speculates that we recognize people using two linked neural systems. One deals with the structural content of the face, the other with the emotional connection you have built up with the person (their “interoceptive awareness”). It’s this second emotional pathway that’s possibly damaged in people with Capgras. Someone with Capgras will think that their wife looks like their wife, but that it can’t be her. This is because her emotional “glow” isn’t right. (Chris Fiacconi, Frontiers in Human Neuroscience)
Jupiter fools Alcmene perfectly, right down to the “glow”. But Mercury is less successful with Sosia. And Amphitryo won’t have a bit of it. I guess that Romans had seen or at least heard about this uncommon condition. Plautus too, if not by name. But what interested Plautus was jealousy. He takes a step beyond Capgras Syndrome and uses the mental affliction to dramatize that emotion. You can see why. This notion of the double captures the crazy essence of jealousy and infidelity, and it mocks the logic of jealousy. How can Amphitryo be jealous of “himself”? In the end he grudgingly agrees and accepts the now pregnant Alcmene’s twins as his own (one by Jupiter, and one by himself). He could have exposed them like any other red-blooded Roman in the audience. But he didn’t and the children were Iphicles (his own son) and Hercules (Jupiter’s). Amphitryo still feels jealous. Wouldn’t you? Yet Alcmene did no wrong. That’s usually the way it is with jealousy. It’s all in the mind.
Capras Syndrome is a rare and fascinating illness. I’ve never known anyone who has suffered from it. But the jealous metaphor it can represent in plays like the Amphitryo, the emotional register it offers, and its role in culture, has a very long history. That I have known.
