The following construction can be found in one of the post in the ELU.

  • remembering that the heart fibrils are what vibrate abnormally to cause a heart attack

The verb "to vibrate" is in the third person plural, and the subject pronoun has for antecedent a plural noun; this is apparently normal, but only apparently so (an innate notion of singular agreement impinges upon my mind, yet not in any exclusive fashion, the logic of a plural taking over incessantly); numerous existing cases show that given a plural antecedent, the agreement of the verb can be either plural or singular; cases "a" and "b" below, respectively, are some examples.

(ref. a1) some other role must be found for it. Motivating reasons are what is believed;

(ref. a2) Since the actual behaviours and decisions are what is of interest to us,

(ref. a3) The rules and principles that emerge from these sources are what is compendiously called constitutional doctrine.

(ref. a4) But rather they are what is nearest and least dangerous to the rioters.

(ref. b1) Listening and being heard are what are important.

(ref. b2) A workable definition of what we mean by 'drugs' has been used, albeit a circular one, so that drugs are what are usually included in the debate about drugs.

(ref. b3) Degrees of height are what are now referred to. The natural mind, by its two capacities called rationality and freedom, is in such a state as to be capable of ascending through three degrees

(ref. b4) The elements of design are what are actually on the film frame, such as points, lines, planes, shapes, and colors.

I cannot get at any source treating this case. There should be a clear-cut rule about this agreement, or so I imagine for now as I have not given this problem enough time to fathom any real intricacies. If so, what is it?

  • Does this answer your question? Is this correct: "Our listeners are what make X"? I believe that non-interrogative 'what' can stand for either 'the thing that' or 'the things that'. – Edwin Ashworth Feb 6 at 15:55
  • @EdwinAshworth yes, it does, granted user herisson didn't fail to identify any relevant sources. Then, there is no clear-cut rule and we are left with a mind-boggling semantic problem for each occurrence of this construction. – LPH Feb 6 at 16:16
  • I don't think many ambiguous cases arise. Often, a rephrase to avoid awkwardness (in Orwell's eyes/ears, worse than ungrammaticality) is best. And some juxtapositions sound far worse than 'It's us!' Consistency is usually good. – Edwin Ashworth Feb 6 at 16:22
  • @EdwinAshworth "But rather they are what is nearest and least dangerous to the rioters.", "Listening and being heard are what are important.": there are plenty of such cases; personally I read just as well "are" in the first and "is" in the second; I don't think it too easy to explain, often. Of course, simply using another construction is a solution. – LPH Feb 6 at 16:29
  • I agree; notional agreement is far better than crude one-size-fits-all approaches. But there is the odd occasion when I disobey ('More than one idea was suggested') and the odd occasion when I rephrase. – Edwin Ashworth Feb 6 at 16:43