Not Quite out of Thin Air
I'm having a blast working on my novel. Ideas are jumping out at me from all over. This is actually problematic, though, in a way. One very cool idea popped up from a suggestion by one of my alpha readers. He said something like "why don't you have the POV say 'x' instead of 'y.'" At another point he said something like "why not say 'blah, blah, blah' in the opening to make the hook stronger." These were very specific suggestions.
Now this guy is a good friend. And when I tried his suggestions, I liked the effect on the writing. Light bulbs went on and the writing took off in some very exciting ways. Plus, his advice IMO did improve a passage of dialogue, and made the hook stronger. But is this ghost writing? If I use his suggestions in the final draft, does that make him a co-author?
How do pros deal with lines that they get from others? For instance, sometimes I overhear someone use a phrase or saying in a cool way and I use it verbatim in my stuff. I have sometimes got entire scenes from listening to strangers talk on the bus or at an adjacent table at a restaurant. And I assume many writers have their radar on like that. But if one of the people I overheard had come to me and said "use this line verbatim in your stuff" I'd feel like I'd been hijacked. Lol. Logically it's still me getting a line or idea from someone else, i.e. I didn't pull it out of thin air. But emotionally it feels very different, much less original.
I have never been around editors, agents, or even fellow writers much. So I don't know what is normal in terms of editorial feedback. But I have heard that some professional writers sometimes make major alterations to their work based on suggestions from others. Call it "research." And often take elaborate steps to keep from having to share credit, i.e. non-disclosure agreements. But at what point does using someone else's input make an author's writing become someone else's writing?Answer:
Whenever I get a suggestion or criticism from someone about how to improve a piece of writing -- whether they are an editor, client, etc. -- I first consider if their suggestion has merit and whether it fits my intention for the piece. If so, then I try to find an even better way to address their concern -- an even better way to write the piece than what they suggest. I try not to take their ideas verbatim but as a challenge
to go one step further.
This practice has the added advantage of avoiding some of the issues you raise.
I also don't use alpha or beta readers much (or critique partners, as writers usually call them). I know that many writers find them invaluable, but it's just not my nature to show anyone my work-in-progress until it's almost completely polished.
For instance, what happens when your critique partner has a very different vision for the story than you do? Do you feel pressured to follow their advice? And if you don't, do you lose them as a critique partner? Sometimes the old adage applies that "a camel resembles a horse designed by a committee."
Of course, it is a different case if you have brought your manuscript as far as you can on your own and then you want to hire an editor, plot doctor, or other expert to help you go a step further (or are lucky to have a friend who's well qualified). At that point, they are less likely to attempt to change your vision of the piece. But if you're going to take any of their ideas verbatim, you should have an agreement with them regarding copyright.
Sometimes, all people want in exchange for their suggestions is an acknowledgment, such as a thank you in the printed book.
In 99% of cases, there's not enough money involved for anyone to bother suing you for copyright infringement. Most published books lose money, after all, and the vast majority of manuscripts never get published. But there are rare instances where a book does phenomenally well and goes on to be made into a film or TV series, and then it might be worth someone's effort if they can prove a line came from them (an email for instance).
But you can't go wrong if you don't take their ideas verbatim.
Regarding lines you overhear spoken by strangers on the street, I would say they are fair game. Certainly, the people involved will never realize they've been quoted. It's extremely unlikely they will remember the conversation or you. And even if they did, they can't prove you quoted them.
Things friends say might be a different matter, because your circle of friends might know exactly who your character is based on. It's best to make fictional characters a combination of several real people rather than one person -- not because there's a risk of being sued, but because you don't want to offend a friend.
P.S. If your friend is as helpful as you say, you could also consider writing a book with him and sharing credit. It might be fun.