"Foolishness," Severus said softly. "Utter foolishness. The Dark Mark has not faded, nor has its master."
"See, that's what I mean by formally insufficient Bayesian evidence. Sure, it sounds all grim and foreboding and stuff, but is it that unlikely for a magical mark to stay around after the maker dies? Suppose the mark is certain to continue while the Dark Lord's sentience lives on, but a priori we'd only have guessed a twenty percent chance of the Dark Mark continuing to exist after the Dark Lord dies. Then the observation, 'The Dark Mark has not faded' is five times as likely to occur in worlds where the Dark Lord is alive as in worlds where the Dark Lord is dead. Is that really commensurate with the prior improbability of immortality? Let's say the prior odds were a hundred-to-one against the Dark Lord surviving. If a hypothesis is a hundred times as likely to be false versus true, and then you see evidence five times more likely if the hypothesis is true versus false, you should update to believing the hypothesis is twenty times as likely to be false as true. Odds of a hundred to one, times a likelihood ratio of one to five, equals odds of twenty to one that the Dark Lord is dead -"
"Where are you getting all these numbers, Potter?"
"That is the admitted weakness of the method," Harry said readily. "But what I'm qualitatively getting at is why the observation, 'The Dark Mark has not faded', is not adequate support for the hypothesis, 'The Dark Lord is immortal.' The evidence isn't as extraordinary as the claim." Harry paused. "Not to mention that even if the Dark Lord is alive, he doesn't have to be the one who framed Hermione. As a cunning man once said, there could be more than one plotter and more than one plan."
"Such as the Defense Professor," Severus said with a thin smile. "I suppose I must agree that he is a suspect. It was the Defense Professor last year, after all; and the year before that, and the year before that."
Harry's eyes dropped back to the parchment in his lap. "Let's move on. Are we certain that this Prophecy is accurate? Nobody messed with Professor McGonagall's memory, maybe edited or subtracted a line?"
Albus paused, then spoke slowly. "There is a great spell laid over Britain, recording every prophecy said within our borders. Far beneath the Most Ancient Hall of the Wizengamot, in the Department of Mysteries, they are recorded."
"The Hall of Prophecy," Minerva whispered. She'd read about that place, said to be a great room of shelves filled with glowing orbs, one after another appearing over the years. Merlin himself had wrought it, it was said; the greatest wizard's final slap to the face of Fate. Not all prophecies conduced to the good; and Merlin had wished for at least those spoken of in prophecy, to know what had been spoken of them. That was the respect Merlin had given to their free will, that Destiny might not control them from the outside, unwitting. Those mentioned within a prophecy would have an glowing orb float to their hand, and then hear the prophet's true voice speaking. Others who tried to touch an orb, it was said, would be driven mad - or possibly just have their heads explode, the legends were unclear on this point. Whatever Merlin's original intention, the Unspeakables hadn't let anyone enter in centuries, so far as she'd heard. Works of the Ancient Wizards had stated that later Unspeakables had discovered that tipping off the subjects of prophecies could interfere with seers releasing whatever temporal pressures they released; and so the heirs of Merlin had sealed his Hall. It did occur to Minerva to wonder (now that she'd spent a few months around Mr. Potter) how anyone could possibly know that; but she also knew better than to ask Albus, in case Albus tried to tell her. Minerva firmly believed that you only ought to worry about Time if you were a clock.
"The Hall of Prophecy," Albus confirmed lowly. "Those who are spoken of in a prophecy, may listen to that prophecy there. Do you see the implication, Harry?"
Harry frowned. "Well, I could listen to it, or the Dark Lord... oh, my parents. Those who had thrice defied him. They were also mentioned in the prophecy, so they could hear the recording?"
"If James and Lily heard anything different from what Minerva reported," Albus said evenly, "they did not say so to me."
"You took James and Lily there?" Minerva said.
"Fawkes can go to many places," Albus said. "Do not mention the fact."
Harry was staring directly at Albus. "Can I go to this Department of Mysteries place and hear the recorded prophecy? The original tone of voice might be helpful, from what I've heard."
Light glinted from the reflection of Albus's half-moon glasses as the old wizard slowly shook his head. "I think that would be unwise," Albus said. "For reasons beyond the obvious. It is dangerous, that place which Merlin made; more dangerous to some people than others."
"I see," Harry said tonelessly, and looked back down at the parchment. "I'll take the prophecy as assumed accurate for now. The next part says that the Dark Lord has marked me as his equal. Any ideas on what that means exactly?"
"Surely not," said Albus, "that you must imitate his ways, in any wise."
"I'm not dumb, Headmaster. Muggles have worked out a thing or two about temporal paradoxes, even if it's all theoretical to them. I won't throw away my ethics just because a signal from the future claims it's going to happen, because then that becomes the only reason why it happened in the first place. Still, what does it mean?"
"I do not know," said Severus.
"Nor I," she said.
Harry took out his wand, turned it over in his hands, gazing meditatively at the wood. "Eleven inches, holly, with a core of phoenix feather," Harry said. "And the phoenix whose tail feather is in this wand, only ever gave one other, which Mr... what was his name, Olive-something... made into the core of the Dark Lord's wand. And I'm a Parselmouth. It seemed like a lot of coincidence even then. And now I find out there's a prophecy stating that I'll be the Dark Lord's equal."
Severus's eyes were thoughtful; the Headmaster's gaze, unreadable.
"Could it be," Minerva said falteringly, "that You-Know-Who - that Voldemort - transferred some of his own powers to Mr. Potter, the night he gave him that scar? Not something he intended to do, surely. Still... I don't see how Mr. Potter could be his equal, if he had any less magic than the Dark Lord himself..."
"Meh," said Harry, still looking meditatively at his wand. "I'd fight the Dark Lord without any magic at all, if I
