This is the subject that's been bugging me for quite some time now, even though I believe I've managed to grasp the entire reported speech pretty well.
If I want to repeat to someone what I previously said about my opinion on swimming, I could go either with #1:
- I said I didn't like to swim.
if I didn't want to emphasize anything, or with #2,
- I said I don't like to swim.
if I want to make it clear that my not liking to swim still holds true.
What I can't understand is why I have to switch tenses back if I'm talking about things like:
- He didn't know California was on the West Coast.
It's obvious that California hasn't moved a single inch, so why can't I express it by saying:
- He didn't know California is on the West Coast.
Similarly, is such shifting required in every utterance of such meaning? For example:
- I told you it was impossible to fly.
It's obvious that no matter how hard I tried I still wouldn't be able to fly. So can't I say "is impossible" (#7) in this case?
- I told you it is impossible to fly.
Best Answer
I agree with @Cord's answer and comment about defaulting to the past tense. I simply wish to add some references so that the OP can make up his or her mind about the acceptability of sentences such as I told you it's impossible to fly.
Firstly, this is what the Collins Cobuild English Grammar (p327) has to say about the "default" use of the past tense:
The CCEG then goes on to state:
Swan in Practical English Usage (p251) writes:
Huddleston and Pullum in A Student's Introduction to English Grammar (p47) state:
Yule in Explaining English Grammar (p272) states:
Quirk et al. in A Comprehensive Grammar Of The English Language (p1027) state:
They list several examples, including:
Finally, Huddleston and Pullum, in the monumental Cambridge Grammar of the English Language, currently the most authoritative descriptive grammar (p155), state:
In a lengthy discussion of contexts in which the present tense is likely to be retained by the reporter, they state:
If we contextualise the flying example, we could say that the backshift is more likely if the telling happened a long time ago. Maybe 5 years ago your friend told you he was working on a pair of wings so he could fly to the shops. Now, after 5 years of fruitless attempts, he tells you of his failure. You then remind him of what you said:
As Cord says: "We are more concerned about the report itself (the source and context of the information)".
Conversely, imagine that your friend comes in one day with a pair of wings and tells you she is going to fly around the garden. You tell her it's impossible. She then makes several unsuccessful attempts, at the end of which you remind her of what you said an hour before:
The emphasis here is on the general (and present) impossibility of flying and not on the telling.