Exception:
Use apostrophes with capital letters [sic -- the first example uses a lowercase letter] and numbers when the meaning would be unclear otherwise.Examples:
Please dot your i's.
You don't mean is.
If you were looking at the link I posted before editing my comment, search for "tired" and "DO use the apostrophe to form the plural".
My 1992 Little, Brown Handbook says:
Use an apostrophe plus -s to form the plurals of letters, numbers, and words named as words.
That sentence has too many but's.
Remember to dot your i's and cross your t's, or your readers may not be able to distinguish them from e's and l's.
At the end of each chapter the author had mysteriously written two 3's and two &'s.
[...]
Exception: References to the years in a decade are not underlined [italicized] and often omit the apostrophe. Thus either 1960's or 1960s is acceptable as long as usage is consistent.
Examples: Please dot your i's. You don't mean is.
Correct or not, the style guide is lame. A clearly superior way to prevent the ambiguity with unfortunate clear default is to use single quotes on both side of the 'i'. So 'i's, not i's.
I intended Leveling Up in Rationality to communicate this:
But some people seem to have read it and heard this instead:
This failure (on my part) fits into a larger pattern of the Singularity Institute seeming too arrogant and (perhaps) being too arrogant. As one friend recently told me:
So, I have a few questions: