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On one particular Friday afternoon, he stated a conjecture that he hoped was true, and invited us to try to help him prove or disprove it.

This kind of professor/researcher/teacher needs more praise. One of the first engineering courses I took when I started out in higher education was taught by such a person.

Maybe it's just me, but I never felt so welcomed and included during my time in higher education as when that lecturer told a bunch of first-year students "here are some things we haven't figured out which you can help with, let me know if you come up with something". It was inspiring and a great introduction to what's otherwise a rather dull first couple of years of academia.

I agree. I didn't mean to imply the article should have stated that. I just wanted to add to the article with additional context that's hopefully helpful to some HN readers.

The article doesn't really state why one would do this, so here's my reason: I'm the sort of person who likes to challenge myself to geometrical problems, but I'm not good enough at it to do any higher maths.

Flight simulation, or, more specifically, finding my way around the sky by radio navigation aids scratches that itch. The procedures involved are precisely solving simple 3D geometrical problems on the fly.

I was thinking of the British Empire. Their naval technology was superior enough to overpower the distance term.

I was under the impression the Dutch didn't really wage interstate war in the same sense, but rather that a bunch of paramilitary private organisations happened to fly Dutch flags. I have to admit I know very little about the Spanish case, but again I thought they mainly fought proxy wars with other European colonial powers, i.e. both were equally disadvantaged by distance.

It's not exactly rocket surgery, is it? Because they are fighting on the other side of the world. I feel like the article glosses over this way too quickly.

It's not surprising the US aren't winning. It's surprising they are at all able to do something that resembles waging war at that distance. Wars are incredibly hard to fight away from home. On the other side of the world? There is basically only one country in the history of ever that has been able to do that.

The article does go on to discuss the Kuwait case and that's a meaningful discussion to have, because actually winning a war so far away is surprising. It's interesting to dig into why that might have been, and the article briefly does. But why they aren't winning is less interesting.

For more meat on how important a factor distance is, Bueno de Mesquita's The War Trap presents one of the most accurate models for predicting wars[1] I know of. That model measures the fighting ability of a country by two factors:

1. It's at-home military power as a sum of population size, metal production, fuel consumption, military expenditure, etc.

2. It's power projection as the distance between its capital and the closest point of enemy land.

Note that the second number is weighted equally to the sum of all other factors, because wars are a logistical nightmare.

[1] https://entropicthoughts.com/war-what-is-it-good-for

On a similar note, people are way too precious about their dead-tree books. Feel free to chuck them in bags, make notes in the margins, fold pages, underline, and strike through text in them. It's yours. Make it yours! Your scribblings don't detract from what's in there – they elevate it to something unique.

(This is particularly true if it's a book that's still in print, or was in large enough print runs it's easy to buy another second-hand copy when the one you have falls apart. It's still somewhat true even when that's not the case.)

Not a single 24-hour analogue face? That unexpectedly turned into one of the best reasons I keep carrying my smartwatch.

Because for it to be effective it must have reasonable cost compared to the benefit. The cost for such a sweeping lifestyle adjustment seems quite high, and the authors have not showed any benefit to interventions.

The article never says anything about causation. It says sleep regularity is a predictor of mortality. That means if you find someone who already has poor sleep regularity they're more likely to die sooner, not that if you force someone into a bad sleep schedule they will become more likely to die sooner.

Self-stopping is called autonomation (or jidoka) in lean/Toyota terms. It's born out of the realisation that automation is capable of producing mistakes at a very high rate, so anything automated needs a way to detect when it's operating outside of the narrow envelope for which it is designed, and shut itself down.

Vaguely related realisation I had a couple of years ago: if you don't need a complicated mobile app, but just something simple for your own use, you can write and run Perl scripts in Termux and there you go – an app, without learning any Android at all!

Not only must there be trust, but there must also be a resolve to make deeper fixes to problems surfaced through the andon system. It's a typical mistake to forget that part. If the response to a problem is patching over the immediate symptom, then the cord will keep being pulled for the same reasons so often no work will end up getting done.

Then the andon system is abandoned as "didn't work for our organisation".

Workers should pull the andon cord (and thus stop the entire production line!) when they need to go to the bathroom, for example. The solution is not to sternly tell the worker to hold it for longer, nor to have a replacement worker come over, but to review scheduling and include more appropriate bathroom breaks between shifts at the line. (Or, if the problem affects one worker disproportionately, figure out some alternative way for that worker to contribute.)

That one probably comes from maths, where surfaces show up all the time in geometric interpretations of things. I've been involved in more mathsy parts of engineering and I've heard it a lot.

I see why you're confused. Some of these tags carry nutritional information, so it's easy to assume they all do.

The healthy tag is about marketing. It's a product positioning statement.

Fun fact: this procedure word is meant to be sent as a single symbol with no inter-letter spacing.

Depends on how it is used! Recording speech nearly verbatim is bad for retention; summarising in own words along the way is good for retention.

Longhand forces summarisation, but it's still possible with shorthand.

For anyone interested in optimising this further, orthographic (letter-based) cursive shorthand systems are the answer. I personally only know part of the Melin system[1], but there are variants designed for English as the primary language too. (Melin is of course perfectly usable with English also.)

The flow of a cursive shorthand system is unmatched by anything else. I highly recommend learning enougnh to experience it.

(The drawback with more phonetic systems like Gregg is that one has to learn entirely new ways of spelling words. But normal English spelling is so complicated that tradeoff can be worth it for heavy usage. Orthographic systems often also contain phonetic components, but they tend to be optional extensions that improve efficiency, rather than required like with purely phonetic systems.)

[1] http://melinsstenografi.nu/image/sti-ukast.png

I used to read a lot when I was small but then fell out of the habit. Rekindled it with my first child. With them I spent a lot of time walking around at all hours of the day to get them to sleep. That were perfect reading opportunities, and I have continued to always carry a book. As TFA says, that is key.

With generated code you'll search for a long time

The observability people will claim that if the dynamic runtime behaviour of your system makes it hard to find the source of a behaviour, your system must be made more transparent and observable. They would also claim this was always the case -- we should never have relied on people's mental models being amazing because people move around.

(I don't know yet where I stand on this but I'm trying to learn more.)

There are so many reasons it's hard to be exhaustive.

Selfishly, nobody will love me like my children, at least in their early years. They're also amazing playmates and students. And they give me social permission to do silly things like climb on playground structures. They're also a great excuse to get out of stuff.

Selflessly, I believe me and the mother of our children are sensible people and the world needs more sensible people. Plus someone needs to maintain the replacement rate. And it's a weird, warm, fuzzy feeling to care for one's children at one's own expense.

In the intersection, it's a fun challenge to try to achieve balance in life, work, and family. I also really appreciate the chance to get a do-over of everything my parents did, keeping the good stuff and improving on the bad.

This can be tricky. I know my mother loves me unconditionally, but I also have strong memories of her shutting herself inside her study to read textbooks and journals, and children were not allowed to disturb unless she was strictly needed to handle an accident.

I have the same need for cognition as my mother, but I opt not to lock myself in my office. Instead I tell my kids, "I'm around if you need me and I'll keep an eye on you but I'm not currently a playmate; I'll be here reading on my phone."

The difference is my mother clearly separated relationship-building from study. I don't. This probably means I'm available more often, but with lower quality? I'm not sure. What is better? No idea.

That's not quite what "skin in the game" means in this context.

The Economist does not need to be right, they only need their readers to believe they are right. That's not quite the same thing, and that small difference is what separates "skin in the game" from not having it.

They can get readers to believe they're right either by being right, or by being ambiguous enough to appear right in multiple futures. Professions where there's skin in the game don't have ambiguity and persuasiveness as an escape to the same degree.

Indeed. OpenStreetMap is the better map, Google Maps is the better address book and business directory.

The great thing about OSM is that if an area someone cares about is sparsely covered, that's a self-solving problem. There are parts of the world with great detail in OSM only because I happen to care about them.

I often reference this comparison in this context: https://i.xkqr.org/gmapsvsosm.png

More concretely, as many as half of the users of a popular programming language will have less than four years of experience: https://entropicthoughts.com/python-programmers-experience

I am very impressed by the simulator, and I really wish I could defend taking time to dig into PDP-1 programming. You make it look like an absolute blast!

So far my children have not yet had to repeatedly perform complicated calculations, but I look forward to the day. I will definitely teach them with nomograms before we go on to spreadsheets!

Another type of almost-nomogram that's great and practical is the slide rule. In particular in the kitchen, where it makes it really easy to translate proportions. https://entropicthoughts.com/kitchen-slide-rule

I've had similar thoughts and ended up going with FreeBSD and no network connection for my use case. It's been great. It gives you some of the expected terminal ergonomics (and USB support) without the distractions.

Neat. This is based on Bayes' rule in its odds form[1], or more specifically in log-odds form, where evidence is additive[2].

[1] https://entropicthoughts.com/bayes-rule-odds-form

[2] https://entropicthoughts.com/sensitivity-counts-against-you