Conventional footnotes considered harmful

Writers use footnotes — equally, endnotes — intending that they be optional for the reader. A note will hold a citation, technicality, or explanation, any of which is of interest to only some readers. This is a useful tactic, in principle.

Footnotes are indicated with ordinal symbols. A cue to a note may be a number, letter, or sequential symbol (commonly, *, †, ‡, etc). In any case, the reference only indicates where the note is, in the sequence of all notes present, rather than anything of the note's content.

So, if you wonder whether you'd care for the content of a note, you have to look at the note, switching to the bottom of the page and breaking your focus. Thus the notion that footnotes are optional is an illusion. The false option is even worse in the case of endnotes in printed works; there, to get to the note, you have to flip across many pages.

Good solutions exist, but are underused:

• Decide, for each detail, whether to include it in the main text or leave it out entirely, rather than leaving some as "optional" in notes. I usually do this myself. Parentheses and em-dashes can help when a detail is hard to work in grammatically.
• Include, in the cue to each note, a hint as to its content, besides just the ordinal pointer. A one-letter abbreviation, standardised thruout the work, may work well, e.g.:
  • "c" for citation supporting the marked claim
  • "d" for a definition of the marked term
  • "f" for further, niche information extending the marked section
  • "t" for a pedantic detail or technicality modifying the marked clause
• Commit to only use notes for one purpose — say, only definitions, or only citations. State this commitment to the reader.