Is the following sentence grammatically correct to write in literature?

How could I not but close my eyes?

As "I could not but close my eyes" is a valid sentence, I felt like this one should also be valid. But I am confused whether 'could not but' can be used like that in interrogative sentences.

  • 4
    Interestingly, the construction could not but.... appears to have hit a peak of popularity in the 1820s - and has been declining ever since. So, yes it's grammatical but somewhat archaic. books.google.com/ngrams/… Commented Nov 23, 2019 at 22:56
  • I for one am having difficulty working out what it adds up to. If I met this in a book, I would be perplexed and have to work out what the writer meant: they had to close their eyes, or that they couldn't.
    – Colin Fine
    Commented Oct 3, 2020 at 12:18
  • 2
    The cited usage is effectively "emphatic repetition". I can say either How could I not laugh? OR How could I but laugh? with exactly the same meaning (I had to laugh). But to my ear today, the "double negation" of How could I not but laugh? sounds a bit weird, to say the least. It reminds me of I could / couldn't care less, where the meaning is the same regardless of how boolean logic and negation apply to the actual words used. Commented Nov 8, 2021 at 15:43

2 Answers 2


Ronald is correct, this is archaic usage.

The difference between: "How could I not but close my eyes?"

and: "How could I not close my eyes?"

is that the first one is more like "How could I do anything else besides closing my eyes", it explicitly invokes rejecting the possibility of alternatives. The second only mentions not doing something.

This is a very small distinction of meaning, and the first use (with 'but') will never be used by modern speakers. You'll encounter it in some literature, however.


As you can see from this Gngram, both could not but and could but are possible, and although they were in decline in the last century, they seem to be currently picking up:

enter image description here

The idiomatic phrase is cannot but, and yes, it is antiquated and more formal:

You use cannot but, could not but, and cannot help but when you want to emphasize that you believe something must be true and that there is no possibility of anything else being the case.

  • [formal, emphasis]
  • e.g. She could not but congratulate him. (Collins)

This example means that "all she could do was to congratulate him".

As for can but it has a similar meaning:

Can only.

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