In the early years, while I tapped away every morning imagining that my novel would be finished soon, the editor of a local anarcho-syndicalist newspaper for which I sometimes wrote suffered from an interesting delusion. He believed that the writer Thomas Pynchon had been writing letters to his paper in the guise of a bag lady who lived under a bridge in Fort Bragg and drank in a bar called the Tip Top. Why did he think this? I don’t remember. The letters were funny, crazy, vivid. The editor found people who believed him, and even helped publish a scholarly, heavily-footnoted volume of the letters (and his own famously funny, vivid replies). The volume parsed every line of the letters for Pynchon lore; not surprisingly, the letters contained the seeds of other Pynchon novels, and references to Gravity’s Rainbow, V and Vineland abounded, all excruciatingly documented. Pynchon ended up having nothing to do with writing those letters to the paper. But the volume exists – made in equal parts of imagination and argument – an almost perfect work of fiction.
The truth turned out to be another story, revealed when the letter-writer murdered his wife – bludgeoned her to death and kept her maimed body in their cabin until it began to decompose. Days later the letter-writer drove his truck off a cliff, killing himself and causing further insult to his wife. The letter writer, the killer, turned out to have been a frustrated poet. The letters to the paper – and the scholarly work they inspired – represented the zenith of his literary career, and the work for which he will be remembered.
Even what we think of as “reality” is constructed by imagination. Look at Muammar Gaddafi’s official outfits. Look at a human heart, an eye. Tell me, tell me, where does fiction come from?

Thanks, Sarah. You and JW capture the idea exactly.