In creating the “hopeful, sustainable futures” project, I was struck by a moment of uncertainty. Although I always separate hopeful and sustainable with a comma (this is a phrase I use a great deal in my work), it suddenly occurred to me that I might be wrong. As a native English speaker, I seldom consider why I use punctuation unless I am trying to reduce my use of commas before “and” in a list, or pondering whether yet another em-dash is truly a good idea. I digress. Back to my moment of uncertainty. Was the correct spelling “hopeful, sustainable futures” or “hopeful sustainable futures”?

After some sleuthing, Swan’s Practical English Usage informed me that:

“Before nouns, we generally use commons between adjectives (especially in longer sentences) which give similar kinds of information, for example, in physical descriptions like:
a lovely, long, cool, refreshing drink

I thought that my usage with a comma – as in “hopeful, sustainable futures” – was almost certainly correct, but I still wasn’t certain why. Elisabeth O’Brien’s explanation gave me a bit more confidence in my choice. She explains the difference between cumulative adjectives, which build on one another to modify a noun, and coordinate adjectives, which both have the same weight in modifying the noun.

For example, if we spoke about six large eggs, both six and large are adjectives. BUT, the number six refers to both the eggs, as well as to the large eggs. Really what we are talking about is six + large eggs. This means that we don’t need a comma between six and large. We can test this in two ways: can we separate the adjectives with an “and”, and can we change the order of the adjectives and not end up with a load of nonsense. Let’s try it:

  • six AND large eggs = nonsense
  • large six eggs = nonsense

In order for the phrase to make sense, it has to start with six then move on to large and then move on to the noun. The adjectives are therefore cumulative and no comma is needed.

Let’s think about my example: hopeful, sustainable futures. For me, sustainable and hopeful can be reordered without a problem – I could just as easily talk about sustainable, hopeful futures. I could also easily add an “and” if I wanted to: hopeful AND sustainable futures. The adjectives have equal weight, which means that they are coordinate, which means that the comma is correct. Phew!

Of course, I could change the meaning of the phrase by eliminating the comma, in which case I would be talking about sustainable futures that are hopeful, for example: hopeful sustainable futures. But that’s not what I want to do. So understanding what I mean to communicate is important in choosing to use a comma or not, too.