Thinking By The Clock


I’m sure Harry Potter and the Methods of Rationality taught me some of the obvious, overt things it set out to teach. Looking back on it a decade after I first read it however, what strikes me most strongly are often the brief, tossed off bits in the middle of the flow of a story.

Fred and George exchanged worried glances.

“I can’t think of anything,” said George.

“Neither can I,” said Fred. “Sorry.”

Harry stared at them.

And then Harry began to explain how you went about thinking of things.

It had been known to take longer than two seconds, said Harry.

-Harry Potter and the Methods of Rationality, Chapter 25.

This was the very first lesson of LessWrong-style Rationality I actually started trying to deliberately teach myself as a result of my contact with HPMoR and the sequences. This is the powerful technique of actually Thinking By The Clock.

I used to call it Thinking For Five Minutes, but that technique name is a misnomer. It’s practically a lie-to-children really. Sometimes I think for much less time, about thirty seconds. Sometimes I think for much more time, like a couple of days. Still, in the way that when you first learn martial arts you might stand in an awkward, stiff stance without turning or stepping I first learned to think by the clock in increments of exactly five minutes.


When I first went to a gym to lift weights, I did it with a friend. I didn’t think it was going to work very well (I was a pretty skinny guy) but I wanted to humour them. I sat down on the bench they pointed me at, got a good grip on the heavy thing they wanted me to grab, and lifted it up and down for a while. When they said stop, I stopped. “That seemed kind of fast,” I recall saying, “are we done?” Dear reader, we were not done. This pattern repeated when I first started going jogging with a different friend. I somehow expected the whole running thing to last, you know, until we got bored, which happened pretty quickly.

(If I may say a word in defense of younger!me, he really wasn’t as unfit as this sounds. Soccer was fun and interesting, and I ran around plenty playing that. Stacking haybales got me paid, and I was quite willing to be paid to lift heavy things as long as I was told.)

So it may not come as a surprise to you that when I first encountered a hard intellectual task that was neither entertaining nor immediately profitable, I kind of bounced off. Going by memory, that was probably Calculus. I hated Calculus. I’d sit down at the table to do my homework or study for a test, and find myself reading the problem a couple of times and then glancing at the clock or looking longingly at the Circuit Theory textbook. (My definition of “entertaining” surprised a lot of people.) When the TA asked however, I’d say that I studied Calculus for a few hours. I was sitting at the table, wasn’t I?

Just as sitting on a barn stool in the haybarn[1] will completely fail to get the bales stacked no matter how long you do it, sitting at the desk staring at the clock will completely fail to get the idea of derivatives into my head.


But you know, that’s not exactly the problem Fred and George had in the quote above, was it? They were presumably doing some thinking in those two seconds. So let me talk about a neat bit of cultural anthropology.

When two people are talking, there’s a gap between when one person finishes and the other picks up. Since neither of them know in advance when they’ll be finished talking and periods don’t actually get pronounced, the listener has to wait a short while before starting to speak. If the listener doesn’t wait long enough, they interrupt and talk over the other person. If the listener waits too long, you can get an awkward silence.

I used to be really bad at figuring out how long to wait. I’m told when I was a child it was not uncommon for someone to ask me how I was, and then to have to wait for half a minute (thirty whole seconds!) or more before I would begin to speak. When I did speak, what I’d say would be composed and unexpectedly thought-through. I think what was going on was, I had no idea that you were supposed to respond quickly, within the back-and-forth flow of conversation.

I had to learn that, deliberately forcing myself to start speaking quickly. For a while I made great use of non-committal openings such as “you know, I was thinking about it and...” which allowed me to gain an extra few precious seconds to figure out what I wanted to say next. Eventually though I got decent at the skill and now I find the silences as awkward as most people. It’s often easy for me to pattern match a shallow, accurate-enough comment that fits the tone of the conversation and just say that. If I do, then often the conversation flows smoothly along. Yay, success!

Then this simple exchange in some funny Harry Potter Fanfiction made me realize that I’d learned to cut off my thoughts after a second or so if I was in conversation, and this sometimes made me say really stupid things. Once you’re aware of this, sometimes you can get people to say stupid things themselves by setting up a slightly too-quick cadence of conversation and gently guiding them away from stopping to think.

Did I say that was something you could do to other people? Well guess what- people can do it to you too.

Perhaps the most dramatic occasion where I have used the skill of Thinking By The Clock was during a job interview. It had been an interview with multiple rounds with multiple different people, and at this point I was talking to the HR department. We had a good conversation going about what I thought about the office layout, what kinds of work I was excited about, and then they asked me without any indication that this was a different kind of question what kind of salary I was looking for.

Reader, I could see the obvious, accurate-enough response that would keep this friendly conversation going. I had put a bit of thought into this before arriving at the interview, I could just pull that cached number out quickly and we could keep talking. I was about to. I’d practiced the skill of keeping a conversation flowing often enough. Fortunately though, I’d also practiced the skill of noticing an important question I shouldn’t blithely continue past. I didn’t stop the conversation completely cold, but I did say a variation on “that’s an important question, and I don’t think it would be an obstacle if we decided we were a good fit. Let me think it over and I’ll get back to you? I’m curious what range you had in mind.”[2][3] They pushed back a bit, and I did stop the conversation for thirty seconds to actually think through my answer.

There are many moments in an ordinary person’s life when you will be asked a question in conversation which will require you to think. The norms of conversational flow will suggest you think for a few seconds at most. These norms are lovely when talking about the weather or how the kids are doing, and they are antithetical to questions of how to best achieve a long range project or how to solve a difficult question.

I have used Thinking By The Clock in work meetings. (Adam: “How do we add this feature to the UI?” Bella: “How about as a sidebar?” Adam: “Great, that sounds good.” Me: “I’ve got an idea. Lets each think about this for two minutes and write down our ideas, then we share the ideas?”)

I have used Thinking By The Clock in discussions with my girlfriend. (No, I’m not giving you an example right here. If you’re that curious how my romantic life works, I’m poly, feel free to ask me on a date sometime.)

You don’t actually need the social pressure of the conversational gap to make this a useful technique. That’s just where I see people make this mistake most often. Selection bias though, obviously I don’t see as many mistakes other people make when they’re alone.

The skill to practice is to spot that you just tried to think very quickly, and to check if this is a decision which you would like to think about more. The technique you would like to train is that instant of noticing, the tiny alarm bell saying you should give your reply or it’ll be an awkward silence when that alarm bell is full of lies. If this was one movement of a kata in the martial art of rationality, that movement would start by being posed a question and would let you open your mouth to give a quick answer before catching yourself and taking the time to actually Think By The Clock.

Start with five minutes. Train yourself to use the time. Then practice smaller increments. Do not allow yourself to goof off or be distracted.


All off that is about thinking too fast and needing to slow down. What about the other direction?

Sometimes I hear someone say they’ve been thinking about a difficult problem for weeks, months, or even years. Sometimes that person is me! It can be both true that someone’s been thinking about it for years and that good thinking is happening, but I often doubt it.

My mother gave me a cheap guitar as a holiday present when I was around thirteen. I found the instrument fascinating, playing with it to try and find out what sounds it could make. I had heard guitar music of course, but nobody in my family or immediate circle played. I kept the guitar with me for the next fifteen years, pulling it out of my closet or from under the bed in my dorm room or from the back of my car to fumblingly tune it, pluck a few strings, look up a chord or two, and enjoy the sound of it filling the room.

You could have said I played guitar for years, and it would have been true, but it would have been exceptionally misleading. Over the first decade I would be surprised if I spent more than a hundred hours with the guitar on my lap, and only a dozen of those hours would have been with an instructor or a teacher showing me what to do. Last year I decided I wanted to actually be able to play some music on the guitar, and I’ve probably spent more time actively practicing in the last month than I spent touching the instrument at all in the second year I owned it.

Before I read those lines in HPMoR, I too often thought about something for years in the sense of pulling the thought out of the back closet and noodling around with it for a bit before putting it away. I’ll still use language like that sometimes, but now I have and additional version for when I actually want to find an answer or make something with my thoughts.

Think about the problem like you’re practicing guitar, and you need to do the music for Secular Solstice next month. [4]

If you’re like me, that just threw some things into sharp relief.

Don’t think about it while distracted. Have some way to take notes or carry the information forward to the next session. You need a clear idea of what “good enough” looks like to know if you’re getting there. Be ruthless about discarding lines that won’t lead to the goal, but also don’t keep banging your head against the same brick wall you aren’t making progress on. Don’t say to yourself that you’re working on it when you’re staring at the beguiling Circuit Theory textbook, so full of secrets like Kirchhoff’s Laws and Thevenin’s Theorems (Calculus eventually forced me to give proper battle) just waiting for you to stray.

This is how I thought about the decision to make a wild career swerve in my thirties. This is the approach I used when deciding whether to move out of my home state to the big city. I picked a few weekends, kept those weekends as clear of distractions as I could, and used a stopwatch to actively work on the problem for two whole days by the clock. I expected real progress to be made, even if that progress was in the form of ruling things out or crossing off blind alleys, and I kept trying.

Start with five minutes. Train yourself to use the time. Then practice larger increments. Allow time for breaks and for maintaining your life, but do not confuse making dinner for focusing on a problem.


Thinking By The Clock is one of the more obvious mental moves which I can cleanly ascribe to Yudkowsky’s writing. I wish I could describe how to do it to myself when I was younger, as I would have benefited from the technique. Lacking time travel, the next best thing I can do is explain it in far more words than Yudkowsky used, in case someone did not absorb the core idea and generate the steps to train it into reflex just by reading that conversation between Harry and the Weasley twins. Write A Thousand Roads To Rome and maybe one of them will lead someone there when all the other roads failed.

That is the hard part I think. Not to just absorb the idea, not to realize it’s important, but to practice the move until you do it even against social pressure or when you’re thinking of other things. My best and favourite sensei once told me a story of slipping on the ice while checking his mailbox in the morning, and finding himself moving into a perfect rearward fall. That is the level of ingrained use that a proper martial art of rationality would aim for, I believe.

To be able to think by the clock, even when taken by surprise before you’ve finished your morning coffee. That’s what I aspire to. Ars Longa – the art is long! Tsuyoku Naritai – I want to become stronger!

You never called any question impossible, said Harry, until you had taken an actual clock and thought about it for five minutes, by the motion of the minute hand. Not five minutes metaphorically, five minutes by a physical clock.

-HPMoR, Chapter 25

  1. ^

    . . .okay, this is the inaccuracy that’s going to bug me if anyone points it out. No, there usually wasn’t a stool in the haybarn.

  2. ^

    Lest that sound too practiced, I will admit that I also rehearsed that answer a bit thanks to Patrick McKenzie’s Salary Negotiation advice.

  3. ^

    I’m actually irritated at myself that I didn’t do this in my last job interview. I saw the moment, I flagged the thing to think about, and I didn’t do it both because I valued the other person’s time quite highly and because I considered us to be on a more cooperative footing than is typical for job interviews.

  4. ^

    Fortunately for both Boston and New York City, I am not the main musician for either city’s secular solstice. I’m both hopeful and currently unprepared for the circumstance where I get to play something at Boston’s Solstice. If you happen to visit, feel free to say hello!