Is the second sentence correct English? What is the grammatical role and meaning of "who knows how many jobs"?

...Traditional cars happen to be human sized to transport humans but tiny autos can work in wear houses [sic] and gigantic autos can work in pit mines. Moving stuff around is who knows how many jobs but the transportation industry employs about three million people.

Source: "Humans Need Not Apply"

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    This question has so many issues it is difficult to know where to start. If you checked the spelling and grammar, reduced it to one question that is not proofreading, and made clear what you are actually asking, it might fit on English Language Learners. But you yourself need to make more effort before asking strangers for help. Jul 27, 2018 at 17:24
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    It's a rather clunky colloquial usage. If you replace who / God / Christ knows how much / many with a straightforward equivalent, you'll see what a mess it is: Moving stuff around is an unknown number of jobs but the transportation industry employs about three million people. Not a style you'd really want to emulate. Jul 27, 2018 at 17:25
  • @TimLymington These sentences are from the script of a very popular video called "human need not apply." I was asking if that second sentence grammatically makes sense.
    – sarah
    Jul 27, 2018 at 17:30
  • wear houses? really?
    – Xanne
    Jul 27, 2018 at 18:11
  • Technically speaking, Human need not apply could be seen as a syntactically valid variation on a theme, since things like Irish need not apply were quite common until more enlightened Anglophone countries banned such discrimination. But actually, the video you're referring to is called Humans need not apply, and I suspect only non-native speakers would change it the way you have. Jul 27, 2018 at 18:11

2 Answers 2


"Who-knows-how-many" is used as a substitute for some number. It is an example of a placeholder noun or word, or in this case, noun phrase

I have read 7 books.

I have read who-knows-how-many books.


"who knows how many" is a way of saying you don't know a certain number.

100 people a year are treated for X medical condition, although since it doesn't have symptoms, who knows how many are affected.

You're more likely to hear this sentence spoken than read, as the "who knows how many" is a slight digression from the actual topic of the sentence.

But your sentence sounds strange without additional context because it sort of contradicts itself. If the industry employs 3m, you do know how many.

Here is an example that makes sense:

Moving stuff around requires who knows how many jobs, but the industry as a whole, which includes drivers, office staff, etc employs about 3 million people.

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