What is it about clouds that has such sticking power? Clouds get traction as a metaphor because they are shape-shifters,
literally. As a result they can stand in for many varied cultural
tropes. Want something to represent the one thing marring your otherwise
perfect situation? Done. Want to evoke the nostalgic feeling of
childhood games of the imagination? Done. Maybe you want to draw a
picture of heaven? You're in luck. Clouds as metaphors pepper our language: every cloud has a silver lining, I'm on cloud nine, his head is in the clouds, there are dark clouds on the horizon. Clouds are the lazy man's metaphor, a one-image-fits-all solution for your metaphor needs.
Because of this flexibility, they commonly appear in our books and music. Perhaps the earliest example is in Aristophanes's play, The Clouds, in which clouds are the play's chorus and playwright's voice, but also symbolize the trendy philosophical fluff that Aristophanes was skewering. In a 14th-century mystical text The Cloud of Unknowing, God is surrounded by a darkness, or a "cloud of unknowing" that can only be accessed through feeling and love, not through knowledge. In 1802 William Wordsworth invoked a lonely cloud to represent his solitude, writing, "I wandered lonely as a cloud/That floats on high o'er vales and hills/When all at once I saw a crowd,/A host of golden daffodils;/Beside the lake, beneath the trees,/Fluttering and dancing in the breeze." Philosophical fluff, the unknowability of God, loneliness -- is there anything a pack of moisture droplets can't represent?
Now, I am a Joni Mitchell fan, but her use of the cloud metaphor takes the cloud thing too far, to sappiness and beyond. In her 1969 song "Both Sides Now," she sings:
Bows and flows of angel hair
And ice cream castles in the air
And feather canyons everywhere
I've looked at clouds that way.
But now they only block the sun
They rain and snow on everyone
So many things I would have done
But clouds got in my way.
Obviously, you can see where this is going: clouds as a metaphor for a love turned cold. But if you can overlook the saccharine quality of Mitchell's lyrics, you can see in her cloud metaphor the reason why cloud metaphors are everywhere: because clouds change. Unlike other celestial metaphors -- the sun, moon, stars -- clouds have varying qualities depending on the day, and their range of appearances make them useful metaphors for a range of qualities. Moreover, a shift in cloud cover -- from a blue spotted sky to an overcast afternoon -- can change the whole mood of a day. Because we associate certain weather patterns with certain moods, clouds in writing can be used to evoke a predictable and strong emotional response. They are a writer's goldmine: a metaphor that is flexible and yet still powerful.
One of my favorite authors, David Mitchell (no relationship to Joni Mitchell, as far as I know), has mined the cloud metaphor to represent the journey of a soul, traveling across ages and taking on new forms. In his 2004 novel Cloud Atlas, Mitchell's character in the far-distant post-apocalyptic future says, "Souls cross ages like clouds cross skies, an' tho' a cloud's shape nor hue nor size don't stay the same, it's still a cloud an' so is a soul. Who can say where the cloud's blowed from or who the soul'll be 'morrow?" Clouds can stand for different incarnations of a soul, and they can stand for the quality of change itself.
Whatever form clouds take, literally or metaphorically, we can find meaning in them and project meaning onto them. At this level, they are a more perfect image for remote data storage than anyone could have anticipated. Much like the billions upon billions of bits of information we store, clouds can have whatever meaning we give them, whatever meaning we see in them.