A comma or period that follows a closing quotation mark appears to hang off by itself and creates a gap in the line (since the space over the mark combines with

A comma or period that follows a closing quotation mark appears to hang off by itself and creates a gap in the line (since the space over the mark combines with the following word space)." I don't doubt Feal, but the appearance argument doesn't carry much heft today; more to the point is that we are simply accustomed to the style.