This is an interesting technique for explaining one's "map": upvoted. However I think one should still be careful not to update on fictional evidence (more precisely to update on the fact that this is the map the given person constructed rather than update on the assumption this is the territory).
Right, that's true. In the particular case of The Things They Carried, I'd trust O'Brien moderately well to depict what the Vietnam War was like, since he participated in it.
"how generalization from fictional evidence is bad"
I don't think this is a universal rule. I think this is very often true because humans tend to generalize so poorly, tend to have harmful biases based on evolution, and tend to write and read bad (overly emotional, irrational, poorly-mapped-to-reality) fiction.
Concepts can come from anywhere. However, most fiction maps poorly to reality. If you're writing nonfiction, at least if you're trying to map to reality itself, you're likely to succeed in at least getting a few data points from reality correct. Then again, if you're writing nonfiction, you might be highly adept at "lying with facts" (getting all the most granular "details" of a hierarchical structure correct, while getting the entire hierarchical structure wrong at greater levels of abstraction).
As one example of a piece of fiction that maps very closely to reality, and to certain known circumstances, I cite "Unintended Consequences" by John Ross. It's a novel about gun rights that is chock-full of factual information, because the man who wrote it is something of a renaissance man, and an engineer, who comprehends material reality. As an example of a piece of fiction that maps poorly to reality in some of its details, I cite "Atlas Shrugged," by Ayn Rand (the details may be entertaining, and may often illustrate a principle really well, but they often could not happen, --such as "a small band of anti-government people are sheltered from theft by a 'ray screen'"). The "ray screen" plot device was written before modern technology (such as GPS, political "radar" and escalation, etc.) ruled it out as a plot device.
John Ross knows a lot more about organizational strategy, firearms, and physics than Rand did. Also, he wrote his novel at a later date, when certain trends in technological history had already come into existence, and others had died out as possible. Ross is also a highly logical guy. (Objectivist John Hospers, clearly an Ayn Rand admirer, compares the two novels here.)
You can attack some of the ideas in Unintended Consequences for not mapping to reality closely, or for being isolated incidences of something that's possible, but highly unlikely. But you can attack far fewer such instances in his novel than you can in Rand's.
Now, take the "Rich Dad, Poor Dad" books. Such books are "nonfiction" but they are low in hierarchical information, and provide a lot of obvious and redundant information.
So "beware using non fiction as evidence, not only because it's deliberately wr ong in particular ways to make it more interesting" but more importantly "because it does not provide a probabilistic model of what happened" (especially if the author is an idiot whose philosophy doesn't map closely to reality) "and gives at best a bit or two of evidence that looks like a hundred or more bits of evidence."
I think nonfiction written by humans is far more damaging than fiction is. In fact, human language (according to Ray Kurzweil, in "The Singularity is Near" and "The Age of Spiritual Machines," and those, such as Hans Moravec, who agree with him) is "slow, serial, and imprecise" in the extreme. Perhaps humans should just stop trying to explain things to each other, unless they can use a chart or a graph, and get a verbal confirmation that the essential portions of the material have been learned. (Of course, it's better to have 10% understanding, than 0%, so human language does serve that purpose. Moreover, when engineers talk, they have devised tricks to get more out of human language by relying on human language to "connect data sets." --All of this simply says that human language is grossly sub-optimal compared to better forms of theoretically possible communication, not that human language shouldn't be used for what it's worth.)
In this way, STEM teachers slowly advance the cause of humanity, by teaching those who are smart enough to be engineers, in spite of the immense volumes of redundant, mostly-chatter pontification from low-level thinkers.
Most nonfiction = fiction, due to the low comprehension of reality by most humans. All the same caveats apply to concepts from fiction and nonfiction both.
In fact, if one wishes to illustrate a concept, and one claims that concept is nonfiction, then that concept can be challenged successfully based on inessentials. Fiction often clarifies a philosophical subject, such as in Rand's "Atlas Shrugged" that "right is independent of might, and nothing rules out the idea that those who are right might recognize that they have the right to use force, carefully considered as retaliatory only" and "simply because the government presently has more might than individuals, the majority vote doesn't lend morality to the looting of those individuals." The prior philosophical concepts could be challenged as "not actually existing as indicated" if they appeared in a book that claimed to be "nonfiction."
But, as concepts, they're useful to consider. Fiction is the fastest way to think through _likely implications.
The criticisms of basing one's generalizations from fictional evidence here are valid. Unfortunately, they are (1) less valid when applied to careful philosophical thinkers (but those careful philosophical thinkers themselves are very rare) (2) equally applicable to most nonfiction, because humans understand very little of importance, unless it's an expert talking about a very narrow area of specialization. (And hence, not really "generalization.")
Very little of reality is represented, even in nonfiction in clean gradations or visual models that directly correspond to reality. Very little is represented as mathematical abstraction. There's a famous old line in a book "Mathematical Mysteries" by Calvin Clawson, and Pi by Petr Beckmann that claims "for every equation in a book, sales of the book are cut in half." This is more of a commentary on the readership than the authorship: a tiny minority of people in the general domain of "true human progress" are doing the "heavy lifting."
...The rest of humanity can't wait to tell you about an exciting new political movement they've just discovered... ...(insert contemporary variant of mindless power-worshipping state collectivism).
Just my .02.
"You can tell a true war story if you just keep on telling it." He always says war story, but the principle generalizes.
I have read about half of that PDF and I see where it is getting. The part of a story which describes something true from real life. Which doesn't want to entertain but educate about some truth of life has to follow this pattern. That is the generalization.
Compare with e.g. HPMoR: The fictional world has a plot and may have a morale. But the truth in there is in true concepts and those are represented in fairly comparable way to the 'war stories'. Explanations of scientific methods are just that: Incomplete explanations. And for example the guessing and double guessing of Harry and Quirrell never clearly resolves. That is a truth of real life strategy. I hope it carries over to last arc.
Are you sure you understood the point? I am highlighting a writing technique where you write the same short story over and over again slightly differently to convey a probabilistic model to the reader in a way that is interesting. HPMoR is not quite this; it's a different story every time, with a different lesson every time, that is treated as a sequence of events.
Ah yes. There are at least two aspects in the 'war stories': The 'probabilistic' aspect which indeed I didn't mention and the 'no plot, no sense' part which I do see in the failure to double guess and the confusion it leaves the reader in.
One could argue though that as this is repeated and repeated between Harry and Quirrell and thus kind of probabilistic.
I'm afraid I've never read The Things They Carried or indeed, have any idea what it is, so I didn't find this very helpful.
As encouragement to OP, I haven't read The Things They Carried either, but OP totally makes sense, and it's interesting and helpful, and I'm glad ze posted it. (... But now I realize OP has been edited before I got to it, so maybe parent applied more beforehand. :-)
Before I edited it, it was like the current one with the second paragraph removed, the last two sentences of the third paragraph removed, and the third and fourth paragraph combined into one, roughly. I'm glad gwern posted his comment, though, because I think the post is much better now.
If you want, read it. Hopefully, though, the principle that I was highlighting was clear, wasn't it? While fiction with a probability distribution given for each sequence of events is boring, fiction with many short stories describing the different possible scenarios is interesting, and gives the same probabilistic model.
Should I give examples of how O'Brien does it? I don't know how much I can type out without violating copyright law.
I'd say it was pretty unclear. There are many short story collections; most don't tell and retell the same story. Is he doing this literally, or just metaphorically (e.g. soldiers experience battle many times, and each time is similar but different?). And what is the "storyteller"? Is it told through a framing device?
He literally tells the same story over and over again, differently every time. He has several stories that he does this to. The book is a fictional autobiography; O'Brien was in the Vietnam War, and writes as though he were recollecting stories from the Vietnam War, but the stories are all made up. Here, I found an excerpt that illustrates the principle in a somewhat okay manner.
EDIT: Here, this is better (PDF warning).
It took me until I read The Things They Carried for the third time until I realized that it contained something very valuable to rationalists. In "The Logical Fallacy of Generalization from Fictional Evidence," EY explains how using fiction as evidence is bad not only because it's deliberately wrong in particular ways to make it more interesting, but more importantly because it does not provide a probabilistic model of what happened, and gives at best a bit or two of evidence that looks like a hundred or more bits of evidence.
Some background: The Things They Carried is a book by Tim O'Brien that reads as an autobiography where he recollects various stories from being a story in the Vietnam War. However, O'Brien often repeats himself, writing the same story over again, but with details or entire events that change. It is actually a fictional autobiography; O'Brien was in the Vietnam War, but all the stories are fictional.
In The Things They Carried, Tim O'Brien not only explains how generalization from fictional evidence is bad, but also has his own solution to the problem that actually works, i.e. gives the reader a useful probabilistic model of what happened in such a way that actually interests the reader. He does this by telling his stories many times, changing significant things about them. Literally; he contradicts himself, writing out the same story but with things changed. The best illustration of the principle in the book is the chapter "How to Tell a True War Story," found here (PDF warning, and bad typesetting warning).
A reader is not inclined to read a list of probabilities, but they are inclined to read a bunch of short stories. He talks about this practice a lot in the book itself, writing, "All you can do is tell it one more time, patiently, adding and subtracting, making up a few things to get at the real truth. … You can tell a true war story if you just keep on telling it." He always says war story, but the principle generalizes. At one point, he has a character represent the forces that act on conventional writing, telling a storyteller that he cannot say that he doesn't know what happened, and that he cannot insert any analysis.
O'Brien also writes about a lot of other things I don't want to mention more than briefly here, such as the specific ways in which the model that conventional war stories give of war is wrong, and specific ways in which the audience misinterprets stories. I recommend the book very much, especially if you think writing "tell multiple short stories" fiction is a great idea and want to do it.
I apologize if this post has been made before.
EDIT: Tried to clarify the idea better. I added an example with an excerpt.
EDIT 2: Added a better excerpt.
EDIT 3: Added a paragraph about background.