[MikeNewYork]

Originally Posted by riverkid

One collocation isn't better than another, Mike. We use language to express meaning and the meaning expressed by "can't have + PP", which denotes a past time event is a better version when we want to express something with greater emotion.

'can' can do this because of its modal meaning expresses a greater reality than "couldn't have + PP". Modal 'could' expresses greater uncertainty so it isn't as good a choice when we want to be nmore strident/ more assertive/ more {__}.

Below we see that it is very common to use the purported present tense modals in modal perfect which describes a past time event.

Results 1 - 10 of about 891,000 English pages for "will have already".

Results 1 - 10 of about 71,200 English pages for "shall have already".

Results 1 - 10 of about 3,330,000 English pages for "may have already".

The language just doesn't support your opinions, Mike. Nor does language science. But you keep crankin' 'em out.

Results 1 - 10 of about 56 English pages for "can have eaten".

Plug in some more with specific verbs, here I've used 'eaten' and you'll see that modals operate in all time sequences; that's how tenseless verbs work.

Pass.