Should the addition of context from a parenthetical footnote be 1 directional? [closed]

Question

... Earth's atmosphere limits how far you can see but let's ignore that for a moment. On such a flat world, you will never see a distant object sink out of sight. It would just get smaller with distance as it moves away from you, but so long as you use good enough of optics, you could see it from any distance¹ ...

1. For example, on a flat Earth, you would be able to see the Himalayas from on top of the Rockies with a telescope.

In this statement, the author first writes in the body text to ignore atmosphere limits. This establishes the context that he is now talking about. Parenthetical footnotes are normally meant to add context to the body text; however, in this case the footnote relies on context from the body text to make sense.

• Is the parenthetical footnote assumed to inherit context from the body text, or should the author re-clarify in the parenthetical footnote that they are talking about an Earth without an atmosphere like this?

  • 1. For example, on a flat Earth without an atmosphere, you would be able to see the Himalayas from on top of the Rockies with a telescope.

• Are there any formal style guides that either expressly allow or disallow this kind of 2-directional context reliance?

• If there is no formal style guide, would this be considered confusing, unclear, or self-contradictory to the average reader?

Answer 1

The context of the main text already establishes several things:

• Earth's atmosphere limits how far you can see, but that limit is being ignored.
• Under discussion is flat worlds.
• On such flat worlds, no objects will sink out of sight, but only get smaller.
• The only requirement to see them is good enough optics.

All of those points of information are assumed to be true with respect to the footnote, which provides an example of what's already been described.

The example in the footnote supplies additional information, isolating one instance from among the many in the set of possibilities:

• The world is Earth.
• The telescope is on top of the Rockies.
• The object being viewed is the Himalayas.

A footnote of this type makes no sense unless the context of the main text is understood. As such, the footnote does indeed inherit the context of the main text.

The fact that atmosphere is being ignored has already been established in the main text.

Restating that the atmosphere should be ignored would certainly not be wrong, even if it might be redundant. However, not stating it is also not an error.

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I know of no style guide that conveys explicit guidance around this. It falls more under the nature of simply making sure that everything makes sense.

It would be entirely up to the author to determine if they want to add explicit, albeit redundant, information to the footnote. Perhaps, for example, because they felt it could be misunderstood if they didn't.

While probably not covered under any mainstream style guide, this is something that could be covered by the house style guide of a particular business. If so, that should be followed. If not, then it would be up to the author's personal style.