Devil's advocate here: fictional 'evidence' can play the same role as a hypothetical; it creates a situation in which you can apply your intuition. If I encounter a story (e.g., an anecdote), it gets weighted to the extent that the story makes sense. If it doesn't make sense, it doesn't get weighted because I'll assume unknown factors or assign a low probability that it can be generalized. It doesn't matter so much, in either case, if the story is true or not.
Claiming that a story is true when it isn't is requesting more serious consideration of the plausibility of the scenario than it deserves, but if it the story is possible, it might as well have happened, since everything can happen once.
For example, with respect to the map anecdote, a person can use their own critical faculty (and experience) to decide the role that luck would have had in the survival of the soldiers. The anecdote certainly expressed the idea that impressions and attitude matter, but I also know that a map of the Starbucks locations in Nashville won't be so helpful in finding the Starbucks in Memphis. (...Except that there often will be one off any interstate exit near the downtown. So I might be lucky if I'm on the interstate and both cities have "Main" streets with a Starbucks. And it helps in any case to drive around.)
And there's another example, because I can't say I've actually ever seen a Starbucks on a street called Main Street, but the entire scenario seems plausible and illustrates the point.
I'm not sure I fully agree. Sure, if I can simulate draws from my posterior beliefs about reality, then I can reason from what those draws tell me. Scientists do this all the time when they simulate from a posterior distribution, and we hardly call this "fictional evidence" although, in a weak sense, it is. If that is all you are claiming, then I agree with you.
But when we create narratives to account for the evidence we see, we're almost never doing so by strictly drawing from a well-confirmed posterior. We're almost always doing whatever is sim...
Andrew Gelman has a post up today discussing a particularly illustrative instance of narrative fallacy involving the recent plagiarism discussion surrounding Karl Weick. I think there are also some interesting lessons in there about generalizing from fictional evidence.
In particular, Gelman says, "Setting aside [any] issues of plagiarism and rulebreaking, I argue that by hiding the source of the story and changing its form, Weick and his management-science audience are losing their ability to get anything out of it beyond empty confirmation."
I am wondering if anyone has explicitly looked into connections between generalizing from fictional evidence and confirmation bias. It sounds intuitively plausible that if you are going to manipulate fictional evidence for your purposes, you'll almost always come out believing the evidence has confirmed your existing beliefs. I would be highly interested in documented accounts where the opposite has happened and fictional evidence actually served as a correction factor.
For what it's worth, I personally enjoy a watered-down version of the moral that Weick attempts to manipulate from the story that's discussed in Gelman's post. My high school math teacher used to always say to us, "When you don't know what to do, do something." I think he said it because he was constantly pissed about questions left completely blank on his math exams, and wanted students to write down scribblings or ideas so he could at least give them some partial credit, but it has been more motivational than that for me.