"can't have been" vs "couldn't have been"

[Grammatically_Correct]

.....in meaning between the following two sentences? And, what tense do the sentences represent?

Sentence 1:
That can't have been the only time you cried.

Sentence 2:
That couldn't have been the only time you cried.

G_C

[Alan]

Hi,

Sentence 1 suggests the reference to 'crying' is more immediate - in other words the event that caused the crying has just been described or is in the very recent past

Sentence 2 suggests the reference is back in the past and not related so closely to now.

Alan
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[Grammatically_Correct]

For some reason my reply did not post. I will try it again.

[Grammatically_Correct]

Thx for your reply, Alan.
So you are saying that the reply depends on how recently the events were recounted. Let's say for example, someone tells me they had a very bad fight with a very good friend 2 years ago and that was the only time they cried, which of the 2 sentences would be my reply?

GC

[Alan]

Hi,

As I suggested in my first reply, I would prefer sentence 2 in your sentence referring to two years ago. This is because there doesn't appear to be a connection with now. The inference is 'at that time'.

Alan
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[Grammatically_Correct]

Thx!
I am still trying to understand the difference, thats the reason I posted the query. And, to be honest the difference is still a bit hazy. So, I have more questions. I hope you don't mind.

You say the connection is in the past and not with the present and hence recommend the second sentence. But the first sentence also seems to be refer to the past, since it also contains the past participle 'have been'.
What confuses me is the auxiliary verb 'can't'(present tense) is used with a past participle 'have been' in the first sentence and this makes it difficult to understand the tense of the entire sentence.

[Alan]

Hi,

I think you're worrying too much. The difference is that reference to 'couldn't means at that time. The reference to 'can't' means what you tell me is not possible for me now to believe.

Alan
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[Grammatically_Correct]

[Torsten]

Hi grammatically,

How about writing thanks instead thx? I mean, if you really want to express your gratitude for something you certainly can muster the energy to type the word "thanks" properly?
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[Grammatically_Correct]

I am fine with typing 'thx'. I'll stick with it, thx.

[Efl Teacher]

Hi,
when we say "It can't have been the only time you cried", we are making a very strong guess based on some kind of reason or evidence. The tense is past. When we say "It couldn't have been the only time you cried", we are making just a simple guess about the past. The differnce all lies in the level of certainty. The first one is actually a conclusion you make based on some kind of evidence, the second one is just a simple guess.

[Alan]

Hi,

As I laboriously explained in previous posts on this question, I think it's more a question of relevance to the time of the supposed 'can't' 'couldn't' rather than the degree of certainty. When we say: I can't have lost my new key already, the sense is that this event or non event is recent. When we say: I couldn't have lost my key when I was on holiday, the sense is that the (non) event is in the past.

Alan
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[Efl Teacher]

Hi,
I guess what Alan says and what I 've been saying are both correct depending on the context of situation.The differnce may lie in the time as Alan says or the degrree of certainty as I said, all depending upon the context of situation.