About closing "first example" questions as duplicates

Question

My question was actually provoked by the treatment of this question but let me make up a fictitious example to sharpen and clarify the issues.

Suppose someone posts a question asking for the first story in which Earth is invaded from outer space. Somebody posts an answer with a 1995 story arout an invasion from Rigel, and then somebody else posts an answer with an 1898 story about an invasion from Mars, which is accepted.

Sometime later someone posts a question asking for the first story in which Earth is invaded by beings from Rigel. The new question is immediately closed as a duplicate of the old question, since it is "answered" by the 1995 story.

Subsequently, more invasion-from-Rigel stories are found, earlier than 1995 but later than 1898. These are better answers to the newer question, but they can't be posted anywhere, since the newer question is closed, and the older question already has a better answer.

Of course the newer question could be reopened, but should it have been closed in the first place? By what right did we assume that an answer to a different question was the correct (i.e. the earliest) answer to the new question? And didn't closing the question lower the chances of a better answer being found?

Answer 1

Of course, you're right. Requests for the first example of X can't be duplicates of each other when the two X are different, even if one of them is a particular type of the other. The only case when they might be duplicates is if one question asks for two different first examples and the other one asks for just one of those - although, in that case, the first question might be arguably too broad.

• What's the first example of Earth being invaded by aliens from another planet?

  What's the first example of Earth being invaded by aliens from Mars?

  NOT DUPLICATES. Yes, any invasion from Mars will be an invasion from another planet, but the earliest invasion from Mars is not necessarily the earliest invasion from another planet, and vice versa.

• What are the first examples of (a) Earth being invaded by aliens from Mars and (b) Earth being invaded by aliens from Venus?

  What is the first example of Earth being invaded by aliens from Mars?

  COULD BE DUPLICATES. If that first question was posted today, we'd probably suggest the OP break it up into two separate posts. But if we have a legacy question like this which is well answered, it could make sense to close other things as duplicates of it.

The arguments generally used in favour of closing questions as duplicates based on answers ... don't really apply in this case. If the answer to a question is based on finding a particular quote or piece of information in a story, then another question might be answerable by copy-pasting the same quote. But for "first example" questions, the correctness of an answer depends also on other answers. Yes, that 1995 Rigel story would be a valid example of Earth being invaded from outer space, but that answer by itself wouldn't confirm it as the first invasion from outer space, nor even the first invasion from Rigel. So we should let "first example" questions remain separate unless they're really asking exactly the same thing.