In our first illustrative sentence (No. 17A) the fact that a word of milder, not coördinate, meaning is to follow “or,” is indicated both by the group of words (I should say) and by the modifier (even) preceding the word in the _or_ relation to “independent.” The comma before “or” would be required in the absence of either or both of these modifiers, as shown in Nos. 17A-1 and 17A-2. It is especially needed in No. 17A-2 to distinguish the _real_ from the _apparent_ meaning:
17A. This capital does not make him independent, or, I should say, even aspiring.
17A-1. This capital does not make him independent, or even aspiring.
17A-2. This capital does not make him independent, or aspiring.
The word or words used in modification of an idea expressed either too strongly or too weakly, are aptly called an “afterthought”; and such word or words themselves suggest the parenthetical nature of the added language.
Our next illustrative sentence shows the use of a word that is too weak; and therefore the sense requires a stronger word. The sentence is particularly interesting because it is a type of sentences that are almost invariably punctuated wrong, even by our best writers:
18. It is a matter of whim, or, worse, of economy.
The word “worse” is introduced to characterize what follows. It is a short form of “what is worse.” It requires a comma before it to cut it off from “or,” and a comma after it to cut it off from what follows. When cut off, the sense relation between “whim” and “economy” is made unmistakable. But sentences of this type are, as stated above, almost invariably punctuated wrong; and the sense relations are thus obscured. The wrong punctuation is as follows:
18-1. It is a matter of whim, or worse, of economy.
In the next illustrative sentence (No. 18A) the new word is simply one that more nearly expresses the writer’s meaning. The comma before “or” is clearly required; but why put a comma after “easier”?
18A. It belongs in the lower, or, as it would be better to call it, the easier, grades of work.
The comma after “easier” acts with the comma before “or” to suspend what comes between “lower” and “grades,” just as a similar group of words is suspended in Sentence 3-1.
