Now his parents were getting into one of those arguments again, one where his mother tried to make his father feel guilty, and his father tried to make his mother feel stupid.

— And I know that I’d just make myself unhappy by comparing that reality to... something perfect that I built up in my imagination.

Sometimes good intentions weren’t enough, sometimes you had to be sane.

— That sort of thing is the reason why I have trouble trusting adults. Because they get angry if you even try to reason with them. To them it’s defiance and insolence and a challenge to their higher tribal status. If you try to talk to them they get angry. So if I had anything really important to do, I wouldn’t be able to trust you. Even if you listened with deep concern to whatever I said — because that’s also part of the role of someone playing a concerned adult — you’d never change your actions, you wouldn’t actually behave differently, because of anything I said.

Harry counted to ten inside his head, which for him was a very quick twelve billion three hundred forty five million six hundred seventy eight thousand nine hundred ten.

Draco’s eyes were wide again.

— Did you really?

Harry gave Draco a puzzled look.

— If I lied the first time, I’m not going to tell you the truth just because you ask twice.

Harry’s thoughts flashed back to possibly the worst moment of his life to date, those long seconds of blood-freezing horror beneath the Hat, when he thought he’d already failed. He’d wished then to fall back just a few minutes in time and change something, anything before it was too late...
And then it had turned out to not be too late after all.
Wish granted.
You couldn’t change history. But you could get it right to start with. Do something differently the first time around.

This whole business with seeking Slytherin’s secrets... seemed an awful lot like the sort of thing where, years later, you would look back and say, ‘And that was where it all started going wrong.’ And he would wish desperately for the ability to fall back through time and make a different choice...
Wish granted. Now what?

Harry slowly smiled.
It was a rather counterintuitive thought... but...
But he could, there was no rule saying he couldn’t, he could just pretend he’d never heard that little whisper. Let the universe go on in exactly the same way it would have if that one critical moment had never occurred. Twenty years later, that was what he would desperately wish had happened twenty years ago, and twenty years before twenty years later happened to be right now. Altering the distant past was easy, you just had to think of it at the right time.

And another piece of paper popped into his hand. Harry took it out, staring at it. It too was in his own handwriting. The note said:


Harry nodded slowly. «Recognition code 927, I am a potato» was indeed the message he had worked out in advance — some years earlier, while watching TV — that only he would know. If he had to identify a duplicate of himself as being really him, or something. Just in case. Be Prepared.

— Um... you seem like a very intelligent person. Or a picture of a very intelligent person... anyway, have you heard of a mysterious game where you can only play once, and they won’t tell you the rules?

— Life, — said the lady at once. — That’s one of the most obvious riddles I’ve ever heard.

God he loved his Time-Turner and someday, when he was old enough, they would get married.

Harry was taken by surprise, both by the sudden appearance of Professor Quirrell’s face and by the resemblance to Muggle television. There was something both nostalgic and sad about that, it seemed so much like a piece of home and yet it wasn’t really...

Harry stepped forward and put his hands on the rock, trying to find some angle from which to lift it without cutting himself:

— I’ll put it in my pouch, then.

Dumbledore frowned:

— That may not be close enough to your person. And what if your mokeskin pouch is lost, or stolen?

— You think I should just carry a big rock everywhere I go?

Dumbledore gave Harry a serious look:

— That might prove wise.

— Ah... — Harry said. It looked rather heavy. — I’d think the other students would tend to ask me questions about that.

— Tell them I ordered you to do it, — said Dumbledore. — No one will question that, since they all think I’m insane. — His face was still perfectly serious.

— Er, to be honest if you go around ordering your students to carry large rocks I can kind of see why people would think that.

— Ah, Harry, — said Dumbledore. The old wizard gestured, a sweep of one hand that seemed to take in all the mysterious instruments around the room. — When we are young we believe that we know everything, and so we believe that if we see no explanation for something, then no explanation exists. When we are older we realise that the whole universe works by a rhythm and a reason, even if we ourselves do not know it. It is only our own ignorance which appears to us as insanity.

— Reality is always lawful, — said Harry, — even if we don’t know the law.

— Precisely, Harry, — said Dumbledore. — To understand this — and I see that you do understand it — is the essence of wisdom.

— So... why do I have to carry this rock exactly?

— I can’t think of a reason, actually, — said Dumbledore.

— ...you can’t.

Dumbledore nodded:

— But just because I can’t think of a reason doesn’t mean there is no reason.

The instruments ticked on.

— Okay, — said Harry, — I’m not even sure if I should be saying this, but that is simply not the correct way to deal with our admitted ignorance of how the universe works.

— It isn’t? — said the old wizard, looking surprised and disappointed. Harry had the feeling this conversation was not going to work out in his favour, but he carried on regardless. — No. I don’t even know if that fallacy has an official name, but if I had to make one up myself, it would be ‘privileging the hypothesis’ or something like that. How can I put this formally... um... suppose you had a million boxes, and only one of the boxes contained a diamond. And you had a box full of diamond detectors, and each diamond-detector always went off in the presence of a diamond, and went off half the time on boxes that didn’t have a diamond. If you ran twenty detectors over all the boxes, you’d have, on average, one false candidate and one true candidate left. And then it would just take one or two more detectors before you were left with the one true candidate. The point being that when there are lots of possible answers, most of the evidence you need goes into just locating the true hypothesis out of millions of possibilities — bringing it to your attention in the first place. The amount of evidence you need to judge between two or three plausible candidates is much smaller by comparison. So if you just jump ahead without evidence and promote one particular possibility to the focus of your attention, you’re skipping over most of the work. Like, you live in a city where there are a million people, and there’s a murder, and a detective says, well, we’ve got no evidence at all, so have we considered the possibility that Mortimer Snodgrass did it?

— Did he? — said Dumbledore.

— No, — said Harry. — But later it turns out that the murderer had black hair, and Mortimer has black hair, so everyone’s like, ah, looks like Mortimer did it after all. So it’s unfair to Mortimer for the police to promote him to their attention without having good reasons already in hand to suspect him. When there are lots of possibilities, most of the work goes into just locating the true answer — starting to pay attention to it. You don’t need proof, or the sort of official evidence that scientists or courts demand, but you need some sort of hint, and that hint has to discriminate that particular possibility from the millions of others. Otherwise you can’t just pluck the right answer out of thin air. You can’t even pluck a possibility worth thinking about out of thin air. And there’s got to be a million other things I could do besides carrying around my father’s rock. Just because I’m ignorant about the universe doesn’t mean that I’m unsure about how I should reason in the presence of my uncertainty. The laws for thinking with probabilities are no less iron than the laws that govern old-fashioned logic, and what you just did is not allowed. — Harry paused. — Unless, of course, you have some hint you’re not mentioning.

— Ah, — said Dumbledore. He tapped his cheek, looking thoughtful. — An interesting argument, certainly, but doesn’t it break down at the point where you make an analogy between a million potential murderers only one of whom committed the murder, and taking one out of many possible courses of action, when many possible courses of action may all be wise? I do not say that carrying your father’s rock is the one best possible course of action, only that it is wiser to do than not.

Imagine that someone tells you they’re keeping a dragon in their house. You tell them you want to see it. They say it’s an invisible dragon. You say fine, you’ll listen to it move. They say it’s an inaudible dragon. You say you’ll throw some cooking flour into the air and see the outline of the dragon. They say the dragon is permeable to flour. And the telling thing is that they know, in advance, exactly which ex-perimental results they’ll have to explain away. They know everything will come out the way it does if there’s no dragon, they know in advance just which excuses they’ll have to make. So maybe they say there’s a dragon. Maybe they believe they believe there’s a dragon, it’s called belief-in-belief. But they don’t actually believe it. You can be mistaken about what you believe, most people never realise there’s a difference between believing something and thinking it’s good to believe it.

That your strength as a rationalist is your ability to be more confused by fiction than by reality.

The whole point of having deontological ethical injunctions is that arguments for violating them are often much less trustworthy than they look.

Life is not a finite list of things that you check off before you’re allowed to die. It’s life, you just go on living it.

Not every change is an improvement, but every improvement is a change.

What do you think you know, and how do you think you know it?

You couldn’t get any more pointless than giving up before you’d actually lost.

Just because something sounded nice, didn’t make it wrong.

If you handed Professor Quirrell a glass that was 90% full, he’d tell you that the 10% empty part proved that no one really cared about water.

— Will think about it. Will not answer right away, this time, will enumerate risks and benefits first.

— Understood. But remember this: other events proceed without you. Hesitation is always easy, rarely useful.

Stupidity is doing the same thing and expecting a different result.

People become who they are meant to be by doing what is right.

People do not grow up because of time, people grow up when they are placed in grown-up situations.

You can have justice or you can have girls, you can’t have both at the same time.

— Boys, — said Hermione Granger, — should not be allowed to love girls without asking them first! This is true in a number of ways and especially when it comes to gluing people to the ceiling!

— Um, — said Harry. — What Tracey did... startled you?

— Startled me, Mr. Potter? — There might have been a touch of acidity in her voice. — No, Mr. Potter, I was scared. I was frightened. I wouldn’t want to admit to being afraid of just dragons or something, people might think I was cowardly, but when you can hear distant voices crying ‘Tekeli-li! Tekeli-li!’ and there’s pools of blood seeping out from under all the doors, then it’s okay to be scared.

— You could call it heroic responsibility, maybe, — Harry Potter said. — Not like the usual sort. It means that whatever happens, no matter what, it’s always your fault. Even if you tell Professor McGonagall, she’s not responsible for what happens, you are. Following the school rules isn’t an excuse, someone else being in charge isn’t an excuse, even trying your best isn’t an excuse. There just aren’t any excuses, you’ve got to get the job done no matter what. — Harry’s face tightened. — That’s why I say you’re not thinking responsibly, Hermione. Thinking that your job is done when you tell Professor McGonagall — that isn’t heroine thinking. Like Hannah being beat up is okay then, because it isn’t your fault anymore. Being a heroine means your job isn’t finished until you’ve done whatever it takes to protect the other girls, permanently. — In Harry’s voice was a touch of the steel he had acquired since the day Fawkes had been on his shoulder. — You can’t think as if just following the rules means you’ve done your duty.

— Mr. Malfoy is new to the business of having ideas, and so when he has one, he becomes proud of himself for having it. He has not yet had enough ideas to unflinchingly discard those that are beautiful in some aspects and impractical in others; he has not yet acquired confidence in his own ability to think of better ideas as he requires them. What we are seeing here is not Mr. Malfoy’s best idea, I fear, but rather his only idea.

If you think hard enough you can do the impossible.

You only ought to worry about Time if you were a clock.

— Is there some amazing rational thing you do when your mind’s running in all different directions?

— My own approach is usually to identify the different desires, give them names, conceive of them as separate individuals, and let them argue it out inside my head. So far the main persistent ones are my Hufflepuff, Ravenclaw, Gryffindor, and Slytherin sides, my Inner Critic, and my simulated copies of you, Neville, Draco, Professor McGonagall, Professor Flitwick, Professor Quirrell, Dad, Mum, Richard Feynman, and Douglas Hofstadter.

So far as Harry was concerned, the five stages of grief were Rage, Remorse, Resolve, Research, and Resurrection.