When I first stumbled upon the retrograde-analysis tag a year ago, it did not have a definition, and there were only a very few puzzles in this category. One of them was this one, which I liked a lot. It seemed to me that "retrograde analysis" - interpreted in general as "backward reasoning" of finding antecedents from consequents - was a nice stop on the spectrum between lateral-thinking and logic-puzzle. I happened to have an open puzzle at that time which immediately seemed to fit well into this category, and so I added this tag to it. I later added the tag to this question as well.
Naturally, I was happy to see this tag become the subject of the 29th Fortnightly Topic Challenge (and even more so because I wanted to post a real-life puzzle involving a computer program whose output was unexpected). Only to be disappointed to find that 2 puzzles above had the tag removed (mine seems to have been overlooked), and that a tag definition has been (only recently) added to restrict its meaning specifically to board game positions / the history of of gameplay.
Nothing in the words "retrograde analysis" implies that it should relate to board game positions. If its meaning can be expanded from its origin in chess to other board games, then why not expand it in general to the kind of puzzles mentioned above, that were originally tagged as such without much disapproval earlier? Alternatively, if we think that retrograde-analysis should indeed be restricted as per its current definition, then what tag should be applied in its place to the puzzles above?
Some options that I can think of are:-
- retrograde-analysis: Generalize its meaning.
- lateral-thinking: This comes close, but questions in this category tend to, IMO, involve more guesswork / "creative" thinking, contrived situations, deliberate omissions or cunning in the description, and often invite "too broad" answers, whereas the examples above are often real, of an investigative nature, and have only one correct answer.
- mystery: This one's definition actually comes very close, but carries a connotation of "crime" or detective work; which means that someone searching for puzzles with this tag might not expect the kind of puzzles mentioned above.
- reverse-puzzling: The current definition is restricted to the incident itself being puzzle solving, and hence can't be applied.
- A new tag? (probably not...)
TL;DR: Should retrograde-analysis be used not just for board game positions, but for "backward reasoning" puzzles in general (see examples linked above)? If not, which tag should be used for such puzzles?