In my proposed solution to this ongoing thread, I mistakenly switched "first case" and "second case" in the second paragraph. But I have rewritten and reposted my comments here, as a new thread, with apologies (as if grammar were not confusing enough).

RE:

a) Jean would have liked to have seen those letters.
b) Jean would have liked to see those letters.

I would like to hazard a solution to the discussion as to which of these two sentences is the correct one.

They are both correct.

In the first case the predicate of the dependent clause is in the present perfect tense; while in the second case the predicate is in the simple present tense.

In other words, the subjunctive modal 'would' governs, in the first case, a verb phrase in the present perfect (inflected to indicate a state of completion), and in the second case, a verb form in the infinitve (without any inflection to indicate a state completion).

It is simply a difference of how you choose to conceive the imagined enjoyment of Jane in the event she had seen the letters.

In the first case, the speaker imagines Jane has already seen ("have seen") the letters, and is pleased. In the second case the speaker imagines the abstract experience of seeing the letters without any indication of time or completion ("to see"), by which Jane is equally pleased.

Now, unless I'm mistaken, it's merely a different use of tense to express the cause of a hypothetical state in the subjunctive mood.

Your thoughts here.