"couldn't be" vs "cannot be"

[englishstudent]

Hi,

In the following exchange, is it possible to use "couldn't be"?

A: Whom do you think will come here first?
B: It could be John.

Here 'could' indicates possibility. Is it possible to negate it?
"It couldn't be John."

In the above context what is more common in spoken English?
1. "It couldn't be John."
2. "It cannot be John."

Thanks

[Temico]

A: Whom do you think will come here first?
B: It could be John.

The question and reply don't match. It should be:-

A: Whom do you think will come here first?
B: It will be John.
or
B: It won't(will not) be John.
____________
C: Whom do you think will come first?
D: I don't know. It may be John, though.

________
E: Could that be John coming first in the race?
F: I am not sure. It could be John.
or
F: It couldn't be John, for sure!

[englishstudent]

Originally Posted by Temico

The question and reply don't match. It should be:-

A: Whom do you think will come here first?
B: It will be John.
or
B: It won't(will not) be John.
____________
C: Whom do you think will come first?
D: I don't know. It may be John, though.

________
E: Could that be John coming first in the race?
F: I am not sure. It could be John.
or
F: It couldn't be John, for sure!

Thank you, Temico for the different possible answers.
In the original posting where the answer to the question
was 'It could be John', is it not possible that
"I think" is implied? (Similar to 'He is taller than I'
where 'taller than I am" is implied). Or, along
the lines of your last answer (F: It couldn't be John, for sure.)
"It could be John, (but I am not sure)"
Perhaps the part (portion?) in the bracket is redundant,
since 'could' already implies a possiblity and not a surety.

I am unable to explain to someone why "It could be John."
is not the 'correct' answer. Any suggestions in this
regard would be greatly appreciated as well.

Thanks

[Temico]

....is it not possible that "I think" is implied?

The verb used in the original question was "will" so to use "will" in the reply would be most logical/appropriate. However, it is also possible to use "could" in the reply like this, "(I think) John could come first."

[englishstudent]

Originally Posted by Temico

The verb used in the original question was "will" so to use "will" in the reply would be most logical/appropriate. However, it is also possible to use "could" in the reply like this, "(I think) John could come first."

Thanks. Is it a stretch to assume that "who will come first" is implied in
"(I think) It could be John (who will come first)." ?

[Temico]

Is it a stretch to assume that "who will come first" is implied in
"(I think) It could be John (who will come first)." ?

Actually in the reply "It will be John", (I think) is also implied. e.g.
"(I think) it will be John." because the speaker is still not sure.

Consider this question:
A: Do you know the name of that boy?

B1: It could be "John".
B2: I don't know for sure. It could be "John".
B3: It is "John".

Which of the three above replies is inappropriate or are they all appropriate to you, may ask?

[englishstudent]

Originally Posted by Temico

Actually in the reply "It will be John", (I think) is also implied. e.g.
"(I think) it will be John." because the speaker is still not sure.

Consider this question:
A: Do you know the name of that boy?

B1: It could be "John".
B2: I don't know for sure. It could be "John".
B3: It is "John".

Which of the three above replies is inappropriate or are they all appropriate to you, may ask?

Hmm, I think upon giving it some thought,
replies B1 and B3 seem to be inappropriate.
In B2, it addresses the question (do you know)
by saying 'I don't know for sure'. But if
in the question it is implicit that "and if yes, what is it?"
then B1 and B3 are also appropriate. Sorry if
this is splitting hair, but I am unable to decide.

[Temico]

I guess that question was too difficult for you. Allow me to try another one.

Question: What is the capital of India called?

Answer 1: I don't know.
Answer 2: It is called "New Delhi".
Answer 3: It could be Mumbai.
Answer 4: It could be London.

Reply to Ans. 3&4: I didn't ask you what it could be. I asked you what it is. If you don't know, say you don't know or just shut up!

[davethorpe]

Hmm, let's look at the following sentence - "Who's that phoning at this time?"
Some possible answers are -
It's John (I can see his name on the call display).

It must be John (he said he was calling at this time, therefore I have a very strong suspicion that it IS John)
It could/may/might be John (there is a possibility that it is John, all 3 usually mean the same in SPOKEN English)

It can't be John (can't, here functioning as the opposite of "must" in "It must be John")

It couldn't be John (the same as "can't", HERE)

It mighn't/mayn't (may not is more common...) be John
It isn't John (It says Simon on the display..

Oh, will and won't are similar to must and can't respectively. Well, when we're using them to talk about probability..........

By the way, IT COULD BE JOHN only indicates a weak affirmative possibiltiy, whereas IT COULDN'T BE JOHN indicates a STRONG negative possibility. They are NOT opposites!!

[englishstudent]

Originally Posted by Temico

I guess that question was too difficult for you. Allow me to try another one.

Question: What is the capital of India called?

Answer 1: I don't know.
Answer 2: It is called "New Delhi".
Answer 3: It could be Mumbai.
Answer 4: It could be London.

Reply to Ans. 3&4: I didn't ask you what it could be. I asked you what it is. If you don't know, say you don't know or just shut up!

Sorry about my confusion with your seemingly straightforward question in your earlier message.

Actually I was thinking along the same lines when I responded to
your earlier message (about which response is inappropriate for the
question - "Do you know the name of that boy?"). Strictly speaking,
the answer should be a "yes" or a "no". So if the answer is
"It is John." the response to that could be "I didn't ask you what the name is. I asked
you "do you know the name?"" Thinking along these lines I wrote earlier that
B1 and B3 are inappropriate, whereas in B2, the person answering first declares
that he/she doesn't know for sure and then offers his/her guess.

I don't know if I have been able to convey what I mean.

Thanks