I've always heard that monospace characters were the reason for two spaces after a period , but I don't understand that reasoning. To me, a monospaced font woul

I've always heard that monospace characters were the reason for two spaces after a period , but I don't understand that reasoning. To me, a monospaced font would especially require only one space, because the period is already using a lot of space on its own. Wouldn't having a period followed by two spaces–in a fixed-width font–be even more whitespace than in a proportional font?