Spaces, Slashes and Dashes

Spaces are one of the most important elements of design. They have lots of functions, but the primary is to group and distinguish things; we put spaces between words to distinguish them, we put spaces between paragraphs to tell them apart, etc. The mind automatically groups things that are not separated by spaces; the letters between two spaces are grouped as a word, the lines between two horizontal spaces or between two indent spaces are grouped as a paragraph.

Here’s a problem that gives me sleepless nights: If the slash (or the hyphen, etc.) is separating groups of words (instead of single words) and is used without spaces, it visually binds and groups unrelated words from different groups, and tears the real groups apart. This visual situation conflicts with the semantic structure of the phrase.

Here, there’s no problem because the slash is marking an alternation between two single words:

It makes people think about scientific theories/concepts.

Here, the problem arises:

It makes people think about scientific theories/philosophical questions.

Now, the words “theories” and “philosophical” are grouped around the slash without spaces, separated from their real groups (“scientific theories” and “philosophical questions”) by spaces. My mind tends to read this as three groups: “scientific” “theories/philosophical” “questions”, whereas it should read it as “scientific theories” / “philosophical questions”. It can become even worse with three groups: “scientific theories/philosophical questions/political ideologies”.

What can we do? Use spaces, of course:

It makes people think about scientific theories / philosophical questions.

So here’s the tip: If your slash (or hyphen, etc.) is functioning between groups of words instead of single words, add spaces around it. This way, it doesn’t visually group the two unrelated words from different groups, and keeps the real groups intact.

By the way, the recommendation by Robert Bringhurst of using spaced en dashes instead of em dashes without spaces to set off phrases makes a lot of sense to me for this exact reason.

I’m also happy to find out that this rule I inscribed for myself is recommended by The Chicago Manual of Style. Because it makes sense.

Addendum

Within the notation I describe, you can write a sentence like this:

It makes people think about scientific/philosophical theories/questions.

meaning

It makes people think about scientific theories or scientific questions or philosophical theories or philosophical questions.

If the rule I described is ignored, however, it can be read as “scientific” / “philosophical theories” / “questions”, which doesn’t mean anything.