"Seemed to have [...]ed": is this structure grammatical?

Question

I came across the following sentences:

• Defying expectations and maybe logic, people seemed to have combined the countercultural sixties and the achieving eighties into one social ethos.

• I seemed to have broken the pattern, but all the time a classroom was waiting for me.

• Its personality, at the moment when I was about to leave it, seemed to have detached itself from its inhabitants and all the human memories associated with it, and to have become endowed with a friendly charm of its own.

As usual, these sentences in The New York Times appear; and they appear together numerous others where the same structure occurs: seemed to have [...]ed.

Can someone clarify if this structure is grammatical?

Or should we reword the above sentences replacing the words "to have combined", "to have broken" and "to have detached" with, respectively, "to combine", "to break" and "to detach"?

Answer 1

This is a complex topic which Mark Liberman has discussed on Language Log. For what it’s worth, I go along with Geoffrey Pullum’s view that the following are all grammatical, but with the different meanings described in the post:

1. I would like to know Marilyn.

2. I would like to have known Marilyn.

3. I would have liked to know Marilyn.

4. I would have liked to have known Marilyn.

It follows that the examples you give are also grammatical.

http://languagelog.ldc.upenn.edu/nll/?p=3941

Answer 2

Your query is about Infinitive+past participle, and it is a structure namely Passive Infinitive.