Complementizing Comma?

I just finished a book called Deed to Death. To be fair, the plot was tight, but I don't really care for the school of mystery writing that relies on "the driver of the green sedan was worried" and "Toni pulled onto the freeway. Four cars behind the green sedan followed" gimmick. Refusing to identify this menacing figure, and then actually writing sections from his point of view without ever telling us he's the killer - well, let's just say that in order to pull it off you have to be a much better writer than this one is. It feels like a cheat when you discover what's clearly meant to be a dazzling surprise.

But that's not what I want to talk about. The author has an idiosyncratic style, full of sentence fragments instead of complex sentences - like this:

A heavy spring rain had fallen during the night. A cleansing deluge that hammered the grey dust from the surface of the gravel and forged deep puddles across the road leading to the construction site.

I'm not crazy about the simple past, which I think should have been the past perfect - and really? "forged puddles"? But metaphors are tricky - sometimes they work and sometimes they don't. If this one hadn't been on the first page, when I was still easing into the book, I probably wouldn't have paid it so much attention.

But that's not what I want to talk about, either. The main thin she does that jars me is use commas where she's dropped a complementizing that.

Okay, what do I mean by "complementizing that"? The word "that" can be used to introduce a complement clause - a clause filling the slot in a sentence usually filled by some sort of noun phrase. For instance, I knew John and I knew that John was a good man have the same top-level structure. The verb "knew" has a direct object in the first sentence and what you might call a direct object clause in the second - a complement clause, to be precise - and it's introduced by "that". This use of "that" - to introduce a complement clause - is called "complementizing".

Now, in English we can omit the complementizing "that" in the vast majority of cases (not when it's a subject, as "that John was a good man was something we all agreed on", because we have to have it there to signal the approach of a complex subject). And in fact we very often do.

I know you think you're doing the right thing

is far more likely to occur than

I know that you think that you're doing the right thing.

But when you omit it, you don't fill that gap with a comma.

I know, you think that you're doing the right thing

is a very different sentence, and so is

I know, you think, you're doing the right thing.

That latter one is close to incoherent without some context, but could easily make perfect sense - it just can't mean what the version with "that"s does. That needs to be written without the commas.

This author has a tendency to use commas in place of complementizing "that" - not all the time, no, but sometimes. For example:

In that moment she knew, Brian counted her as family.

And then Toni realized, Mark's treachery hadn't ended with Scott's murder.

And then she realized, she was going to pass out.

The first one of these is particularly bad. When she doesn't know, Brian doesn't count her as family? But the other two, while hard to misinterpret, are awkward and jarring, because you're expecting more to the sentence. You're expecting a complement to follow what the comma tells you is a parenthetical. And you don't get it. So you have to go back and start over.

Commas don't separate verbs from their direct objects. And that's true whether the direct object is a simple noun phrase or a complement clause.

I think I know what she's doing. But she's picked the wrong punctuation mark. Far more often than the rest of them, the comma actually serves a grammatical function. It's not just "when there's a pause". In fact, using the "that" in all three of these sentences would have marked that pause more than adequately.