I've often heard people saying this. And even I say it when someone accuses me of doing something that I didn't do.

I'd say:

Why would I do that?

But what's the grammar behind it?

Is it future from the past tense or something or what? It's obviously not a conditional construction 😒

Context from SE01 EP02 Austin & Ally

Austin: what does the jacket have to do with the music video?

Trish: It's a line in Ally's song, "my jacket's in the lost and found."

Ally: "my jacket"? It says "I like it." The line is "I like it when you hang around."

Dez: "hang around"? I thought it said "kangaroo." ♪ I like it when you kangaroo. ♪.

Ally: Why would I write "I like it when you kangaroo"?

  • Do not delete and repost the same question. Edit the original to include the extra context.
    – ColleenV
    Sep 19, 2018 at 17:58

2 Answers 2


Consider the following conditional declarations:

I would do it if you paid me.

I would do it if my life depended on it.

I would do it if I thought it would make things better.

The question Why would I do it? asks "What possible reason or motive would I have for doing it?

In your example:

"What possible circumstances would lead me to write I like it when you kangaroo?"

  • but in that context there is no condition
    – user82287
    Sep 19, 2018 at 16:20
  • 1
    @user82287: Exactly. With Why would..? the question is asking "Under what conditions ...?" The question is incredulous. By asking, the asker is saying "It is ridiculous or very weird that you would think there would be some conditions under which I would have written that. What could they possibly be???"
    – TimR
    Sep 19, 2018 at 16:21
  • okay it's kind of clear now. but the examples you gave are in present tense. and in my given example it's past. so shouldn't it be why would I have done it? or is why would I do it used for both past and present? that's what I wanna ask
    – user82287
    Sep 19, 2018 at 16:23
  • @user82287 Why would I write is not in the past tense.
    – TimR
    Sep 19, 2018 at 16:24
  • 1
    @user82287 She is not referring to that particular act of writing in isolation. Rather she is saying "Why would I ever write something like that?"
    – TimR
    Sep 19, 2018 at 16:27

Question: Why would I do that?

Assertion: I would close the window right now. [implication in the background, which is not always actually spoken: If I were you or if I were cold.]

Question: Why do I always close the window?

Assertion: I always close the window when I am cold.

would do is conditional.

Person One: You left the dog outside all night and it was cold.

Person Two: Why would I do that?

[If it were cold: background] Why would I do that?

would do is conditional. The entire idea is not always spelled out clearly in conversations or dialogue but it is always in the background. And the idea is some kind of conditional utterance.

  • but the 2nd person did leave the dog outside. then why did he say why would I do that?
    – user82287
    Sep 19, 2018 at 14:48
  • this isn't what I meant. Can I provide the context
    – user82287
    Sep 19, 2018 at 15:48
  • just to make it clear what I meant?
    – user82287
    Sep 19, 2018 at 15:48

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