Art and dreams make something of a shamefaced couple nowadays. I blame Dallas. In order to resurrect the soap's only buff cast member, Bobby Ewing, Pam wakes up to the convenient fiction that the entire seventh series was a dream. Emerging from the shower, dripping masculine assurance all over the lino, Bobby listens to her bonkers summary of the past year and replies: "None of that happened. I'm here now."
But it wasn't always so. Dreams and art have had a long, fertile relationship, as I discovered while researching the history of dreams for a new Radio 4 series. Take the extraordinary work of the 15th-century Dutch painter Hieronymus Bosch, who used the fantastical and the grotesque to explore morality and mortality. His Garden of Earthly Delights teems with fecund, fearful dream imagery: a copulating couple are held aloft in a closing mussel shell; a steely grey figure climbs into a man's carcass, a large arrow extruding from his backside. Images of slippery sin and fleeting pleasures, of enduring pain and terrifying pointlessness lurk everywhere in the triptych. Our sweetest dreams, Bosch seems to say, prefigure heaven; our most terrifying nightmareshell. But the central panel, which depicts the here and now, is also discomfortingly dream-riddled. Life, Bosch implies, is as fleeting and ephemeral as a dream.
Like a dream, art both is and isn't true. Both offer a challenge to the tyranny of realism, replacing what is with what might be. Both generate an altered state of consciousness removed from the humdrum – and both lend themselves to interpretation. That's where the fun starts. To dream of faeces, a modern dream key drearily explains, means that "some part of your life needs cleaning up". An Egyptian papyrus from the second millennium BC is more upbeat on the subject: it goes as far as to say that eating your own excrement equates to "generating possessions in one's own house". Intercourse with a cow is "good – passing a happy day", while sex with your mother means "your clansmen will support you".
In Homer's Iliad, from the eighth century BC, Zeus sends "Wicked Dream" to Agamemnon urging him to attack Troy. It is almost like a character. Dreams here have an existence independent of, and external to, the dreamer. They arrive as visitations, potentially bearing messages from the gods. In the lexicon of Homer, dreams are entities that sleepers "see". Over the centuries, though, we have come totake possession of them: dreams today are things we "have".
In times of upheaval, dreams can offer radical alternatives, giving artists a way to speak dangerous truths. Shakespeare's Midsummer Night's Dream contains what could have been, for the author, fatal allusions to the sexual life of Queen Elizabeth I. Contemporaries would immediately have recognised Titania, the fairy queen, as a fictional rendering of their ageing, virgin monarch, whose continued refusal to provide the nation with an heir threatened anarchy. Titania, like Elizabeth, also refuses to share her bed, which throws the entire natural world into chaos. In punishment, she is subjugated to masculine rule, and forced to bed an ass. In light of all this, Shakespeare wisely structures his play as a dream vision, ending: "If we shadows have offended,/ Think but this, and all is mended,/ That you have but slumber'd here,/ While these visions did appear." Bobby Ewing couldn't have put it better.
Shakespeare's Dallas disclaimer is undone, though, by the fact that Puck – a sprite, an imaginary creature – delivers it. The Puck of Shakespeare's 1590s play, gadding about sprinkling love juice on the eyes of sleepers, has little truck with divine truth. But he's related to a vibrant pagan belief, in which erotic dreams were thought to be the work of nocturnal spirits. Succubi explained wet dreams. They were female spirits who seduced sleeping men to steal their sem*n. These succubi would then transform into incubi, male spirits, who would impregnate witches. Such ideas had surprisingly widespread currency. In the Pendle witch trials of 1612, a dream was admitted as evidence that its dreamer, Elizabeth Southerns, was bewitched. Her dream? A little brown dog had tried to bite her armpit, and thereby suckle her blood.
In the wake of the great examples of the Bible, including the enduringly popular, sartorially splendid dream analyst Joseph, dreams characterise the poetry of the medieval era more than any other. In William Langland's epochal poem Piers Plowman, written between 1360 and 1387, a quest for true, Christian self-knowledge begins with our narrator Will falling asleep in the Malvern hills. Decades of Will's waking life are passed over without comment; it is only in his dreams that his search for truth can be conducted. This tells us that to the medieval mind, corporeality is erroneous andflawed. Dreams – freedfrom the gross, sin-stained body and potentially emanating from the divine – might be more real than waking reality. Senses lie, dreams speak the truth.
With the dawn of the Enlightenment, and its insistence on knowledge demonstrable to the senses, the idea that dreams might originate from outside the sleeper faded. But, as the Romantics were to discover, this did nothing to lessen their power – particularly frightening ones. Nightmare imagery stalks gothic fiction and ignites the art of the time, as the 1781 painting The Nightmare by Henry Fuseli shows: a swarthy goblin squats on an erotically supine sleeper as a mad-eyed mare looms out of the darkness behind.
Coleridge was plagued by nightmares so powerful he would routinely wake his entire household with his screaming. Why, he asks, in his 1803 poem The Pains of Sleep, were his dreams poisoned with "desire and loathing" and visions of an "unfathomable hell within"? Men whose lives were "stained with sin" might expect as much. But, he demands, bewildered and palpably afraid, "wherefore, wherefore fall on me?"
In a sense, it was in answer to this question that Sigmund Freud, a century later, began his investigations into dreams. Freud's radical claim was that all our dreams – even the most terrifying – are wishes. The more difficult or dangerous our desires seem to our conscious selves, the more peculiar or terrifying their nocturnal expression will be. Dreams, Freud concluded, are "the royal road to the unconscious".
The idea that dreams reveal aspects of ourselves that we are unable to grasp in daylight underpins most contemporary discussions of dreams, even among those who (like my iPhone autocorrect) read Freud as nothing but a well-read fraud. His sexually charged theories propelled dreams to the centre of 20th-century culture. The wildly expressive art of Dalí, Miróand Magritte, and the writings of the surrealists, used dream imagery in a bid to access and unleash authentic human experience.
Freud didn't silence a centuries-old debate, then. He reignited it. What our dreams mean is one of the oldest and most persistent questions in human history. And, despite their tawdry coupling in Dallas, it's extremely unlikely this ancient fascination has ended. What the history of dreams ultimately illustrates is the measure of our closeness to, as well as our distance from, the long-dead dreamers of the past – since, as Jack Kerouac said, "All human beings are also dream beings. Dreaming ties all mankind together."
Lucy Powell presents Our Dreams: Our Selves on Radio 4 at 1.45pm, daily until Friday.
Pass the opium: five of the most influential dreams in art
Penelope's dream of Odysseus
In The Odyssey, Penelope sees Odysseus's return in a highly symbolic dream, but is unsure whether to trust it. Dreams that issue from gates of horn, she says, are true, while those from the gates of ivory are deceptive, an image that would echo down the centuries. One explanation could be that when horn is polished it becomes translucent, whereas ivory remains opaque.
Jacob's ladder
In the Bible, Jacob, father of Joseph, dreams of a ladder bridging heaven and earth that angels traverse. This dream was hugely influential in the middle ages, when dreams were thought to link the temporal and the eternal, the human and the divine.
The House of Fame
This early poem by Chaucer, over 2,158 lines long and thought to have been written in 1379, is one of the most sophisticated literary dreams. The narrator begins with a summary of all the possible causes of dreams, before recounting one in which he was transported by an eagle to a glass-roofed temple adorned with images of the famous and their deeds. Chaucer comically establishes a connection between dreaming and creativity, while holding fame to be as fickle and illogical as a dream.
Kubla Khan
In September 1797, Coleridge took laudanum, a tincture of opium, after reading about Xanadu, the summer home of the titular 13th-century Chinese emperor. He fell asleep and experienced a long poetic vision. On waking, he began transcribing it when a young man from Porlock interrupted him. After which, Coleridge could remember nothing more. The fragments he did set down have become one of Romanticism's most enduring poems.
Irma's injection
In 1895, Sigmund Freud was treating a patient he called Irma. The treatment ended prematurely and was only partially successful. He then had a dream about Irma, in which she opened her mouth to reveal alarming white patches on her throat. A colleague then gave her an injection with what Freud feared was a dirty needle. Freud eventually interpreted this dream as an expression of his desire not be held accountable for Irma's continued illness, and his wish to be seen as a capable, conscientious physician. From this point on, Freud would argue that all our dreams, however odd or terrifying, are wishes.
