(Anonymous)
Dumbledore explicitly says he was sure that there was more than one, because of the casual treatment and nature of the diary Horcrux. Dumbledore certainly knew that there was something strange about Harry's scar, but that matches the prophecy (mark him as equal).
Dumbledore certainly knew that there was more than one after seeing the Diary; we know that because he doesn't say, "This is great! Now Voldemort is *really* dead!"
However, neither does he start looking for other horcruxes.
Between that and Dumbledore's words to Harry at the end of CoS about Voldemort having given him some of his powers, Dumbeldore had to have known by then, at least, that Harry was a horcrux. He doesn't make it sound like that in HBP, but he didn't want Harry to know yet that he was going to have to die.
If we trust Dumbledore's own words, he only started to suspect a Horcrux in Harry, when Harry came to Hogwarts and reacted on Voldemort's presence.
Under the circumstances, I don't think we *can* trust Dumbledore to be honest. The information we have from him comes from things he said to Harry, and he wouldn't want to tell Harry anything that would lead him to wonder about Dumbledore's actions -- since Dumbledore was, after all, setting Harry up to be killed.
That doesn't mean that Dumbledore was lying, but it means that he'd've said what he did whether or not it was true.
Lynn
Dumbledore certainly knew that there was more than one after seeing the Diary; we know that because he doesn't say, "This is great! Now Voldemort is *really* dead!"
However, neither does he start looking for other horcruxes.
Between that and Dumbledore's words to Harry at the end of CoS about Voldemort having given him some of his powers, Dumbeldore had to have known by then, at least, that Harry was a horcrux. He doesn't make it sound like that in HBP, but he didn't want Harry to know yet that he was going to have to die.
If we trust Dumbledore's own words, he only started to suspect a Horcrux in Harry, when Harry came to Hogwarts and reacted on Voldemort's presence.
Under the circumstances, I don't think we *can* trust Dumbledore to be honest. The information we have from him comes from things he said to Harry, and he wouldn't want to tell Harry anything that would lead him to wonder about Dumbledore's actions -- since Dumbledore was, after all, setting Harry up to be killed.
That doesn't mean that Dumbledore was lying, but it means that he'd've said what he did whether or not it was true.
Lynn