Sentences: Double or Single Space?

[Final-Fan]

RolStoppable said:

Final-Fan said:

Since you've been kind enough to assert an absolute, I can easily supply an example of how double spacing sentences can aid reading comprehension. 

"As both a professional editor and a long-time student of psycholinguistics (the mental perception of spoken and written language) I can state that putting two spaces between sentences is much more reader-friendly when it come to fluent reading and making sense of sentence structure. With just a single space between sentences, one is obliged to concentrate more of one’s attention on determining where the sentence breaks are, thereby distracting from a free flow of the message of the text into one’s consciousness.

"The double space is a much more easily perceptible indicator of a sentence break than a full stop (=period), which is not an infallible indicator of a sentence break, as it is also used to signify an abbreviation. Similarly, capitalisation does not just signify the beginning of a new sentence, it is also used to designate proper nouns. Just take the following example of a single-space break:

"My friend Paul lives on St. Joseph St. Paul is active in his community.

"It takes some stopping and thinking to determine where the sentence break is meant to be. Compare the same two sentences with a double-space break:

"My friend Paul lives on St. Joseph St. [double space] Paul is active in his community.
(I have inserted the term in brackets here as computers tend to change doubles to singles.)

"Granted, this may be a rare example, but it typifies the advantage of the double space between sentences."

People don't get castigated for single spacing sentences because it's considered a legitimate way to use the language, but that doesn't mean that double spacing is useless, or indeed that my example is inaccurate.  I would argue that not capitalizing the beginnings of sentences would not be much more likely to cause confusion for a reader other than by their unfamiliarity with that practice.  I'm not, by the way, arguing that we should do that, or that it's not wrong to do it. 

Okay, so the double space aids terrible writers. What does the second "St." even mean? Also Saint? Or rather Street? Yeah, I guess that has to be it.

"...lives on Street."

I always thought "in" is used in such a sentence. Man, your example is confusing on so many levels. If I had to write the same sentence, then I wouldn't abbreviate Street, because it's just confusing, double space or not. It's for this reason that I try to never end a sentence with "Super Mario Bros.", so I rather use "SMB" instead. I care for my readers, this example person obviously does not. I think this means that good writing goes beyond flawless grammar.

This is just an extreme example of the general point that periods do not reliably indicate the ends of sentences -- and that therefore the double space has value as punctuation. 

I would agree with the author in arguing that the example is not confusing when there is a double space.  It's not "lives on Street".  I don't know what could possibly make you think the first "St." was a "Street".  AFAIK, "Saint" is the natural thing to presume in that case, which is correct here.  And the double space ensures that the second "St." is not thought to be "Saint" as well, since there is a double space proving that "Paul" belongs to a new sentence.  Therefore the reader will not be confused and immediately correctly conclude the second "St." is "Street". 

P.S.  And it is in fact "on", not "in", when it's a street and not, say, a building.