The comma has a way of bedeviling even the most careful of writers, particularly when grammarians can’t come to an agreement on even its most basic function—that of separating elements in a series.
But I digress. Let’s talk about when not to use a comma. More specifically, let’s talk about what’s wrong with the following sentence:
My home was designed by architect, Steve Clark.
I see this a lot, and I’m not sure why. Architect is a nounal adjective modifying Steve Clark. In that sense, it’s no different from any other adjective. Like brown, or enormous, or droopy. Yet you wouldn’t normally see something like this:
Just beyond the brown, house was an enormous, willow tree with droopy, branches.
See? Doesn’t work. Let’s look at another example:
Noted composer, John Cage, would have celebrated his 100th birthday this year.
Noted is an adjective; composer is a noun. Together, they form an adjectival phrase that modifies John Cage. In principle, that phrase is no different from a single-word adjective that likewise serves as a modifier—like, say, controversial or minimalist, neither of which would require a comma in the above example. So let’s fix it:
Noted composer John Cage would have celebrated his 100th birthday this year.
Much better, don’t you think?