The Age Of Physical Type Link
Typography and typesetting used to be surprisingly physical endeavors. Individual letters had to be picked up from cases as objects and put together, one by one, into words, then phrases, then columns. (Before fonts were heavy on websites, they were just heavy.) Colors were inks – actual substances that needed to be mixed and prepared. Preparing and cutting paper was a whole separate industry.
This extended to spacing. Whitespace was not the absence of atoms, it was just atoms… of a different kind. For your page composition to stay in place as it went through the press, you needed not just to put space blocks between sentences, but also pack the entire remaining area with blocks of lead or wood. What today you’d call letter spacing, line height, padding, margins… they were all physical.
In this world, running left-aligned (ragged) text required almost the same effort as full justification, since the spaces still needed to go somewhere. Every fraction of an inch had to be accounted for.