Verifiability, Not Truth - "If It's Written in A Book, IT Must Be True!"

"If It's Written in A Book, It Must Be True!"

In many cases, if something appears in a reliable source, it may be used and attributed where needed, but reliable sources are not infallible. There are examples where material should not be reported in Wikipedia's voice, because what is verifiable is that the source expresses a view, not that the view is necessarily accurate.

• Most sources do not state their opinions as opinions, but as facts: "The hypno-toad is supreme" is more likely to be found than "our opinion is that the hypno-toad is supreme, but there are others who disagree with us." It is the task of the Wikipedia editor to present opinions as opinions, not as facts stated in Wikipedia's voice; this is one reason Wikipedia's voice should be neutral. The best way to describe a dispute is to work with a tertiary source that already describes the dispute and cite it as a reference. Tertiary sources may also help to confirm that there is a legitimate dispute to begin with, and not just a fringe theory against a universally accepted idea.
• It is important not to "cherry-pick" quotations or other material. Source material should be summarized in context to make sure it is represented fairly and accurately.
• In some cases, publication in a reliable source is not sufficient to establish that a view is significant. Reliable sources may be outdated or disputed by other sources. Books from before Pasteur would state the theory of spontaneous generation to be a fact; they are still useful sources to explain that theory, but not to describe the modern state of knowledge on the topic. There are a few immortal authors whose works are never outdated, but they are rare.
• Reliable sources may express speculation, or a source for a significant view may include in it views that are not significant. In these cases, criteria other than those described in our policy on sources are necessary.
• Even the most reliable sources commit mistakes from time to time, such as misspelling a name or getting some detail wrong. Such mistakes, when found, should be ignored, and not be employed to describe a non-existent dispute. To know where we have a dispute and where a simple mistake, consider whenever the author is really an expert on the topic (and not an expert on another topic, making a brief reference to something beyond his area of expertise), or if the text that breaks the mainstream knowledge is provided on purpose or as a mere passing-by comment. For example: George Washington was born in 1732. Let's consider a tourist guide talking about the cities of the United States, such as Washington, D.C. If the guide says "Washington D.C. is the capital of the United States, and it's named after George Washington (1722–1799), the first president of the US...", then that's just a mistake. But if we have an article written by some famed historian, stating something like "New historical evidence would date the birth of George Washington to 1722, 10 years before it was usually known", then it would be a different thing... regardless of whether such a hypothetical claim was true or not.
• Works of fiction about real historical peoples or events must never be used as sources for historical fact, no matter how accurate they may be. Fiction needs to have a beginning, a chain of events, an ending, well-defined characters, etc.; something that reality rarely has. Even more, they may need to twist things for narrative purposes, or add new features where the original lacks them. So, if you want to write an article about Eva Perón, do not use Madonna's film as a source. If you want to write in the Battle of Thermopylae article, do not use 300 as a source. Note, however, they may be used as primary sources to describe the plot of such works of fiction.