How do you parse the following sentence?

The lamp by which she read the book grew dimmer.

My friend says that "by which she read the book" qualifies "the lamp". So, it would basically mean "The lamp that she was using to read grew dimmer."

For some reason, I comprehend the sentence as "The lamp that she was near while reading the book grew dimmer." Can it go both ways, or...?

Also, about the usage of "grew dimmer" there, should it be "dimmed" instead? Thanks.

  • 1
    How else would you parse it, if not as your friend suggests? Oct 7, 2016 at 7:59
  • I was just wondering if it was proper/or if there was a better way to write the sentence.
    – wat
    Oct 7, 2016 at 8:00
  • Yes, very good. You've spotted an ambiguity. Your friend interprets by as a preposition of agency: The lamp by means of which.... You interpret by as a preposition of place: The lamp alongside of which....
    – deadrat
    Oct 7, 2016 at 8:52
  • I am not following. You do not read a book by means of a lamp. You can only read it by means of your eyes (or your fingers if you're blind). You can illuminate it by means of a lamp, and you can weigh it down by means of a lamp, and maybe you can even poke a hole in it by means of a lamp, but you cannot read it by means of a lamp. The lamp does not do the reading. No ambiguity possible in this particular case. To read something by a lamp clearly means near the lamp and nothing else.
    – RegDwigнt
    Oct 7, 2016 at 9:14
  • @RegDwigнt That's what I presumed. Would "The lamp, by which she was using to help her read the book, grew dimmer." be a way to correct the sentence? Also, my friend argues that what you said was correct because it would be like saying you can't vote with a system or a system can't vote in the context of "A system by which people could vote by telephone."
    – wat
    Oct 7, 2016 at 9:35

1 Answer 1


Whichever of the alternative readings you employ, yours or your friend's (both of which are possible), the parsing is no different. ...by which she read the book remains as an adjectival clause qualifying lamp.

The only difference is in the meaning of by. Is it by meaning by means of, or by meaning near.

The main verb is grew. But the sentence would benefit greatly from parenthetical commas after lamp and book.

The lamp, by which she read the book, grew dimmer.

  • My friend argues "by" in "by which" always means "by means of". If the sentence was, "The lamp she read the book by grew dimmer." the "by" could mean either, but not the case with "by which."
    – wat
    Oct 7, 2016 at 8:30
  • The problem with the location reading, for this specific example, is the "grew dimmer" part. If "by the lamp" means "next to the lamp", you'd imagine that she was reading by daylight and just happened to be next to the lamp. Presumably, the lamp was turned off. But in that case, the lamp couldn't "grow dimmer".
    – Greg Lee
    Oct 7, 2016 at 9:13
  • 2
    @AliceNykaza Would your friend therefore argue that the phrase the lamppost by which I was standing is invalid?
    – WS2
    Oct 7, 2016 at 9:50
  • ... To do so wouldn't be too bright. / 'The lamp by which she read the book grew dimmer.' would pragmatically be interpreted as having the agency rather than the locative reading without further context. It would be an error (though not a grammatical one) (arguably worse, I'd point out to grammar-worshippers) not to indicate if this default sense was not the one intended (unless the ambiguity was intended, say in a humorous context). Oct 7, 2016 at 11:00

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