3 ms·
When you're trying to read quickly, a single space makes it harder to spot the end of a declarative sentence because periods are so small. FTA: With two space
by dctoedt 8y ago
When you're trying to read quickly, a single space makes it harder to spot the end of a declarative sentence because periods are so small. FTA: With two spaces, "[t]he space also comes into the periphery of one’s vision before it arrives, and that helps to signal that the sentence is wrapping up. (For the same reason, I've sometimes used bullets • and pilcrows ¶ after periods to better separate sentences.)
The only argument I've ever seen for one space is that two spaces are supposedly ugly because they can cause rivers of white space to run down the page. IMO readability is more important.