> The practice [of two spaces after the period] originally came from typesetting
I'm just challenging that assertion, which is commonplace, but there's plenty of evidence to the contrary, many of which you can see with your own eyes.
Literally centuries of typesetters and
printers believed that a wider space was
necessary after a period, particularly
in the English-speaking world. It was
the standard since at least the time
that William Caslon created the first
English typeface in the early 1700s (and
part of a tradition that went back further),
and it was not seriously questioned among
English or American typesetters until the
1920s or so.
Extra space after each sentence was and is a good idea, whether you're talking about handwritten documents or typeset ones. Typewritten documents arguably benefit the least from the practice. Point being, when single-space advocates say that double-spacing is obsolete and unnecessary because we don't use typewriters anymore, they are just plain wrong.
I'm just challenging that assertion, which is commonplace, but there's plenty of evidence to the contrary, many of which you can see with your own eyes.