"No," said the shadowy figure, voice rising in frustration, "no, no, no! Then you get the wrong answer and you can't go to the Moon that way! Nature isn't a person, you can't trick them into believing something else, if you try to tell the Moon it's made of cheese you can argue for days and it won't change the Moon! What you're talking about is rationalization, like starting with a sheet of paper, moving straight down to the bottom line, using ink to write 'and therefore, the Moon is made of cheese', and then moving back up to write all sorts of clever arguments above. But either the Moon is made of cheese or it isn't. The moment you wrote the bottom line, it was already true or already false. Whether or not the whole sheet of paper ends up with the right conclusion or the wrong conclusion is fixed the instant you write down the bottom line. If you're trying to pick between two expensive trunks, and you like the shiny one, it doesn't matter what clever arguments you come up with for buying it, the real rule you used to choose which trunk to argue for was 'pick the shiny one', and however effective that rule is at picking good trunks, that's the kind of trunk you'll get. Rationality can't be used to argue for a fixed side, its only possible use is deciding which side to argue. Science isn't for convincing anyone that the blood purists are right. That's politics! The power of science comes from finding out the way Nature really is that can't be changed by arguing! What science can do is tell us how blood really works, how wizards really inherit their powers from their parents, and whether Muggleborns are really weaker or stronger -"
"Stronger!" said Draco. He had been trying to follow this, a puzzled frown on his face, he could see how it sort of made sense but it certainly wasn't like anything he'd ever heard before. And then Harry Potter had said something Draco couldn't possibly let pass. "You think mudbloods are stronger?"
"I think nothing," said the shadowy figure. "I know nothing. I believe nothing. My bottom line is not yet written. I will figure out how to test the magical strength of Muggleborns, and the magical strength of purebloods. If my tests tell me that Muggleborns are weaker, I will believe they are weaker. If my tests tell me that Muggleborns are stronger, I will believe they are stronger. Knowing this and other truths, I will gain some measure of power -"
"And you expect me to believe whatever you say?" Draco demanded hotly.
"I expect you to perform the tests personally," said the shadowy figure quietly. "Are you afraid of what you will find?"
Draco stared at the shadowy figure for a while, his eyes narrowed. "Nice trap, Harry," he said. "I'll have to remember that one, it's new."
The shadowy figure shook his head. "It's not a trap, Draco. Remember - I don't know what we'll find. But you do not understand the universe by arguing with it or telling it to come back with a different answer next time. When you put on the robes of a scientist you must forget all your politics and arguments and factions and sides, silence the desperate clingings of your mind, and wish only to hear the answer of Nature." The shadowy figure paused. "Most people can't do it. That's why this is difficult. Are you sure you wouldn't rather just learn about the brain?"
"And if I tell you I'd rather learn about the brain," Draco said, his voice now hard, "you'll go around telling people that I was afraid of what I'd find."
"No," said the shadowy figure. "I will do no such thing."
"But you might do the same sort of tests yourself, and if you got the wrong answer, I wouldn't be there to say anything before you showed it to someone else." Draco's voice was still hard.
"I would still ask you first, Draco," the shadowy figure said quietly.
Draco paused. He hadn't been expecting that, he'd thought he saw the trap but... "You would?"
"Of course. How would I know who to blackmail or what we could ask from them? Draco, I say again that this is not a trap I set for you. At least not for you personally. If your politics were different, I would be saying, what if the test shows that purebloods are stronger."
"Really."
"Yes! That's the price anyone has to pay to become a scientist!"
Draco held up a hand. He had to think.
The shadowy, green-lit figure waited.
It didn't take long to think about, though. If you discarded all the confusing parts... then Harry Potter was planning to mess around with something that could cause a gigantic political explosion, and it would be insane to just walk away and let him do it on his own. "We'll study blood," said Draco.
"Excellent," said the figure, and smiled. "Congratulations on being willing to ask the question."