One can say only God knows in reference to some mystery only an omniscient being would know, or for those who prefer their oaths minced, heaven knows or goodness knows or lord knows.

The inverted form God only knows is also very common. But if read in usual English word order, it means something different, that God knows to the exclusion of anything else— God "only knows," and doesn't see, hear, act, etc.

Why and how then do we say God only knows? Is it a mangled quotation, a holdover from archaic English, or something else?

  • 1
    Definitely an idiomatic phrase, but don't ask me about the origins. Actually, if you want to know the etymology, ask at EL&U - ELL should only tell you "it's an idiom, accept it."
    – SF.
    Mar 1, 2013 at 14:15
  • 2
    Only in God only knows is not an adverb but an adjective, equivalent to alone - and like alone, it is placed after the noun it modifies. Mar 1, 2013 at 14:41
  • @SF I wondered about that, but thought this might be something that trips up learners. That's a good, succinct guideline for the future (unless this gets migrated).
    – choster
    Mar 1, 2013 at 17:57
  • @StoneyB You're right, but in modern English it's far more common for adjectives to precede nouns except in set phrases, so a non-native speaker could reasonably assume that only is an adjective, or that the phrase is not syntactically sound.
    – choster
    Mar 1, 2013 at 18:01
  • The phrase God only knows is centuries old, from a time when only often came directly after the word or phrase it modified, or sometimes even later in the sentence. Although it's not as common anymore, you may still run into examples where only isn't placed where you'd expect it, and you should be able to understand them when you come across them.
    – user230
    Mar 2, 2013 at 0:15

3 Answers 3


"God only knows" is an idiom. These two are equivalent.

As to why James can't just give me a straight answer, God only knows!

I really don't know why James can't just give me a straight answer!

Where the phrase comes from, and why it is inverted is probably a better discussion for ELU.

From the perspective of an English learner, you're just going to have to accept that it's an idiom, and hence you'll have to learn it by rote.


It can mean "doesn't also see and hear etc", but I think you are being presumptive. In addition to word order choice, one also has an emphasis choice which does not get preserved in writing. If I place more spoken emphasis on "only" or even "god only" it becomes equivalent to "only god."

Because it has become very idiomatic, the spoken emphasis is almost unneeded because the phrase is considered understood.

{see also StoneyB's comment}

  • -1. "God only knows" is an idiom meaning "I don't know why this is the case". Even if it could grammatically mean "God doesn't see and hear and know; God only knows", that's a total red herring for an English learner. "God only knows" is never used by native English speakers to mean that.
    – Matt
    Mar 1, 2013 at 23:43
  • You've missed the point. The construction can mean that, which is why the OP stated that it could and expressed confusion. The idiom never means that, which, if you reread what I wrote is what I said.
    – horatio
    Mar 5, 2013 at 16:36

I have heard people say God only knows in the same fashion as goodness knows or lord knows. For example,

"God only knows why she's still working at that company; I would have left a long time ago."

I don't know any historical background on the phrase though.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .