The discussion arises from my own experience examining the writing process and on this topic, breaks down into two considerations. The first looks at common sources open to all writers ‘combing the ether’ for ideas. That which roots in the outside world. The second is more personal and deals with the known vs. the unknown sources inside the writing brain.
    Most writers are receptive to their surrounding world. We note news items ranging from the major to the inconsequential and file them away in our memory, or write them down. As long as they hold interest, they are worth saving for future use in our stories, sometimes on their own, more often combined with other, disparate items, characters, settings or plots. I often read a short story or piece of a novel and see exactly where the inspiration originated because I too took notice of the source material and have either used it in one of my stories or was waiting for the right time and ninety-degree turns to make it interesting. You can’t wait too long, I think these ideas have a shelf-life of one or two years. After that, your idea has been exploited by another writer or the topicality has passed.
    As always, the originality arises in the way each author interprets the key elements and applies them to a human condition worth dramatizing. I’m not saying there’s no such thing as creativity from thin air but we share experience and environment. We need to have depth in our writing and to be accessible to readers who may or may not seek subtext commonality but do seek a unique, accessible and entertaining take on a subject.
    The second manifestation of this subconscious phenomena comes to me in the form of my direct inspirations in novel writing.
    My book “Transient City” owes a bow to Christopher Priest’s “Inverted World” (one Goodreads reviewer got it!). Priest’s mobile city concept struck a chord years ago when I read it and seemed the ideal setting for my tale of endless memory and homage to 1960’s British pop culture. This was a conscious attempt on my part to acknowledge but not imitate.
    I will occasionally re-read a previously-enjoyed book and be surprised by a scene or plot thread which I recognize came forth to a conscious level during my creative process, one I didn’t trace back to source when madly writing a new scene but nevertheless has enough similarity in origin to tag it after the fact. It doesn’t happen a lot but I estimate one or two significant ideas per book which I thought were all me likely have an outside source, though re-imagined to fit my experience and need. This raises a greater question: does the unrestrained, non-editorial free-flow of early drafts/new scenes unleash the creative mind or plumb the memory? Memory isn’t a filing cabinet; it usually doesn’t offer up exact copies of an event. It recreates the event from additive experience to closely resemble the original. Another level of modification or creativity, depending on how askew the ‘new’ differs from the source.
    A mildly scary epilogue to “Transient City” is an old SF novel I discovered recently by Mack Reynolds called “Rolltown”. The cover depicts a large RV, a micro-habitat on treads. The cover of Transient depicts my imagined city perfectly – a town-sized complex on treads. It is coincidence; the similarity ends with the cover. Reynolds’ story takes place on post-catastrophe dystopic Earth, involving masses of RV’s travelling together for safety. I neither saw nor read the book when it came out in 1976 but seeing that cover in the used book store less than a year ago gave me a moment of shock. Perhaps I plumbed forty-year old ether for that one.
    Writers and readers share enough experience, whether cultural, anthropological or global zeitgeist to survive the translation from author’s mind to page to reader’s eyes to their mind hopefully consistent with the creator’s intent. Striking the reader’s tuning fork melodiously is what I seek as a writer. Understanding how I got there is more complex than typing the words on a screen. Who is in charge? In my case, it varies. The end result always amazes my conscious mind, the first reward for hours spent at the screen. The second reward is when a publisher finds it as amazing. The third and most important is when the reader discovers it.