It’s the subject of heated office debates. It distracts some and disturbs others, and others it drives crazy. It estranges husbands and wives, divides the best of BFFs, and alienates whole generations. It’s the question keeping us all awake at night.
One space after the period, or two?
Those of us who grew up on typewriters will always and forever put two spaces after a period. Those who grew up on computers will always and forever use only one.
This is not a problem.
I don’t give a flying university how many spaces you put after a period. You can use 27 and it’s not going to matter. Consistency counts, so you should probably try to be consistent within a given document, but readers—most readers, that is; I try to not even think about punctuation Nazis, who should be jailed just for being jerks—most readers don’t care and aren’t going to notice. And if you’re very worried about it, you probably don’t have enough work to do and you should stop slacking off and get busy.
It’s not the space between sentences that matters but what’s in that space—the invisible ligatures that connect a sentence to the sentences before and after it.
Invisible ligatures: I’m talking about the conceptual links between actual physical points of contact between sentences—links that writers use to join sentences together and impose coherence on a body of information under discussion.
Information has no inherent coherence, no logic, no narrative. We call Aristotle the Father of Western Logic because he was the first to point out that logic has nothing to do with content, nothing to do with truth, and everything to do with form. Logic is a specific formal arrangement of statements that exhibit relationships between the subjects. We impose logic on the world by putting information into a certain form.
The same with narrative and expository development. We have to tell readers a story that leads from a definite beginning to a definite end. That requires that we link each sentence physically to the sentences before and after it.
Here’s how that’s done:
1: Pronouns. Writers sometimes use pronouns and antecedents to link sentences together. As the name suggests, a pronoun is a word that stands for a noun. The noun for which a pronoun stands is called the antecedent, because it usually comes before the pronoun. (But not at the beginning of this essay, where I use the pronoun “it” four times before telling you what “it” is.)
If you have a noun as an antecedent in one sentence, you can link the next sentence to it by using a pronoun:
“Recovery of the species will take decades. During the early phase of this period, the species may suffer further declines.”
“This period”—what period? The “decades” mentioned in the first sentence. The pronoun points readers directly back at what they learned from the first sentence and allows them to move forward to the new information contained in the second sentence.
2. Key terms. Writers often create certain key words or phrases as a way of leading readers step-by-step through a discussion:
“During the early phase of this period, the species may suffer further declines. Our ability to prevent further declines is hampered by our uncertainty about the cause of the declines.”
Here the phrase “further declines” from the first sentence is repeated in the second sentence, again to lead readers step-by-step clearly through the discussion.
3. Adverbs and conjunctions. Writers will often begin a sentence with an adverb such as “however” or an adverbial phrase like “On the other hand” or a simple conjunction like “But” to make explicit the relationship of a sentence to what has come before:
“Our ability to prevent further declines is hampered by our uncertainty about the cause of the declines. However, the agency has taken steps to reduce hunting of the species. Moreover, new research programs are gathering more information that we hope will give us more insight into the causes of the species’ decline.”
Here the writer uses two adverbs, “however” and “moreover,” to situate the two subsequent sentences in relation to the first. “However” lets readers know that the information in this sentence is in some sense antithetical to the info in the first, and “Moreover” tells readers that this information is going to augment something we just learned in the previous sentence.
There are many other ways to create narrative coherence between sentences, but these three examples make an important point: information is not coherent in and of itself. Coherence, logic, narrative: these are things we create, things we impose on the world to understand it better.
Just like a real train, the train of thought needs actual physical connections between its constituent parts so that the reader’s comprehension doesn’t get left behind, dead on the tracks.