As Leech, Geoffrey N. suggests in Meaning and the English Verb §186, could can have the following usage:
#1. Hypothetical equivalent of can (= ‘possibility’)
The house is one of the most beautiful that could be imagined.
#2. Hypothetical equivalent of can (= ‘ability’)
Do you know anyone who could repair this clock for me?
I didn't understand how the hypothetical use was involved in these two examples until I found an explanation from here:
Part 1 If someone is messing around with your clock - but they haven't broken it yet - you can say:
- "Do you know anyone who could repair this clock for me?"
It means: "If you break my clock, who do you think is going to mend it?"
That's a hypothetical question and you have stated it correctly.
Part 2 Some sentences are definitely hypothetical - because that is their grammatical structure; others can be hypothetical because of the way they are used..
If you wanted to, you could go to a baseball game with me
You think I could mend your clock
The first is definitely hypothetical because it has "if" and "could"
The second does not seem to have a hypothetical structure but very often it will mean..
- If for one moment you were to think I could mend your clock then you'd be very much mistaken!
..in which case there is a hypothetical use
I think your textbook (Meaning and the English Verb) is saying that, on the one hand you need to see how the words: if, were, could, would and so on are used to form hypotheses; but on the other hand, you need to know that, in English, hypothesis is sometimes implied with only a hint of those words.
So what kind of context would be apt for #1 so that could could be regarded as a hypothetical equivalent of can (= ‘possibility’) rather than a mere representation of 'real' possibility?
Can you please contrive a hypothetical scenario for Leech's explanation of #1?