It's always better to gain a full understanding of the system when trying to make important decisions.

The trolley has two sets of wheels, leading and trailing, both of which must remain on the same set of tracks.

The switch is designed to enable the trolley to change course, moving from one set of tracks to the other.

Throwing the switch after the leading set has passed, but before the trailing set has reached the switch points will cause the two sets to attempt travel on separate tracks. The trolley will derail, rapidly coming to a halt. If the trolley is moving slowly enough to permit this action, nobody dies.

Source: former brakeman (one of the people responsible for throwing switches), section hand (one of the people responsible for installing switches), and railroad welder (one of the people responsible for field repairs of switches).

Are you serious? They really have what amounts to an exoskeleton? Or maybe it's more accurate to call it a whole-body rib cage?

Just searched and found this fun article. Not really a skeleton but a collection of really stiff hairs or feathers (loosely: the genes are the same ones responsible for "other skin appendages" in vertebrates).

Especially given that using π=3 is accurate enough for most daily use by ordinary people for ordinary things.

What is this stop business? I have it on good authority that it's turtles all the way down.

All great things start in a bar. Or coffee shop. Or in the shower. Or in a dream. But never in a meeting.

Structurally, the most challenging book I've ever read was "The Message of THE QUR ĀN" by Muhammad Asad.

Start with the fact that the QUR ĀN itself is extremely non-linear. So much so that I think that this alone requires a great deal of study to address.

The text is 2 columns, the original Arabic adjacent to his English translation. There are copious and often long footnotes. The footnotes cross reference other footnotes, sometimes in chains. I read only the English.

I had to read it 4 times. Once just ignoring footnotes. Again, this time including just first-level footnotes. Again, following footnote chains back to their sources in the text. Finally, to reread just the text after pretending that I had everything figured out.

It took me a year to get through it to my satisfaction, although it was not the only reading, or even major project.

As a non-geologist living next to Lake Diefenbaker (the reservoir formed by damming the South Saskatchewan River), I also like geological history.

I have a standard reply for when I'm asked why we chose to move to this "treeless wasteland". "I look out at the flat horizon and see how the glaciers planed the earth the way a woodworker flattens a board. I look around me at the river breaks and see how the meltwater from retreating glaciers carved the earth away into shapes that defy imagination." I don't know accurate any of that is, but it fits my mental model of what I was taught in high school.

(What we call the river breaks are twisted and braided networks of coulees, some with sides so steep as to require mountaineering equipment. Most still run with meltwater in the spring.)

There is also the MRI intended to help kids understand what they will be going through.

I read that as:

For decades, Nestle has been patenting milk proteins.

They've been doing it for a long time, not somehow getting extra-long patents.

There is a lot of good discussion here, but I'd like to toss in something else. Look around at the society we live in. Corporations don't care about health and well-being. Insurance companies don't care about health and well-being. Political leaders don't care about health and well-being. Pundits and think tanks don't care about health and well-being.

Caring, volunteering, and donation all require the right frame of mind. Between the stress of daily survival and the messages we get from the people with the most power and the loudest voices, it surprises me that anyone is still donating.

At that point, I think pulling it out to an appendix is the right thing to do. Whenever I find a book with appendices, I do one of two things.

1. If an appendix looks like "prerequisite" material, I read it first.

2. If it looks like "further reading" or "deeper dive" material, I note where it's referenced in the main text and return to it later.

The main reason I prefer footnotes to end notes is the separation of concerns. When a book has end notes, they are usually mixed with citations. I don't mind managing 2 bookmarks or the eReader linking back and forth, but I really dislike following the reference to find that it just points at a whole other book.

You've had a couple of pretty good responses. I would add that the very fact that you can ask that question demonstrates a failure of the education system and the fundamental problem of depending on business ideals to manage society.

In the first case, a proper education would have included, at all grade levels, examples and discussion of the various purely intellectual pursuits that ultimately proved critical to some technological advance that improved quality of life.

In the second case, the naive "businessification" of society means that any pursuit that doesn't make clear at the outset what practical (ie profitable) goal is being pursued is dismissed as folly unworthy of funding and support and education. (See my point above.)

I think for maximum uselessness, they should not be overlapping spheres, but deform at the interface, like soap bubbles or rubber balls. As long as the spheres are the same size and modelled with the same "surface tension" or "elasticity", the "intersection" of two sets would then be a circular interface with an area proportional to what would otherwise be an overlap (I think). If the spheres have different sizes or are modelled with different surface tension or elasticity, one would "intrude" into the other.

Multiple sets would have increasingly complex shapes that may or not also create volumes external to the deformed spheres but still surrounded by the various interfaces.

Time to break out the mathematics of bubbles and foam. This data ain't gonna obscure itself!

Might there actually be utility to something like this? Scrunch the spheres together but make invisible everything that is not an interface and label the faces accordingly. I suppose the same could be said of the shape described by overlapping. (Jesus, you'd think I was high or something. Just riffing.)

What you are describing is a failure of education. Maybe not at the university level, but somewhere. When I taught at an adult vocational school in the 1990s, every course started with the same material: how to use a keyboard and mouse, how to use the operating system, how to navigate and use network resources, and how to use foundational software like word processors, spreadsheets , and data entry systems. And how to set up email clients.

We ran our own email server out of the networking class. Yes, it could be a bit flaky, but that just exercised their backup and recovery skills and kept all the email users on their toes. :)

One of the challenging issues with a complex problem is that the problem is not solved until the whole thing is solved.

One of the nice things about a complex problem is that you don't have to solve the whole thing at once in order to make progress toward a complete solution.

I don't know the state of the art on dealing with waste brine. If that is already deemed insoluble above a certain scale, then we better not invest in anything that exceeds that scale. On the other hand, if research into handling waste brine in sustainable ways is ongoing and making progress, then why not continue attacking the extraction problem?

Off the top of my head, I can't think of any advance that didn't at some point depend on people just dicking around to see what they could see.

"What happens if we spin this stick really really fast against this other stick?"

"Cool! What happens if we put some dried moss around it?"

"That's nuts, man! Hey, I wonder what happens if we toss some of our leftovers in there?"

"C'mon over here, guys. You gotta taste this!"

At worst, a project like this keeps a lot of curious people in one place where we can make sure they don't cause harm with their explorations. At best, whole new industries are founded. Never forget that modern electronics would never have existed without Einstein and Bohr arguing over the behaviour of subatomic particles.

Say the actual construction cost is $100 billion over 10 years and operational costs are $1 billion a year. Compared to all the stupid and useless stuff we already spend money on, that's little more than pocket lint. We could extract that much from the spending of one military alliance and it would look like a rounding error. Hell, we could add one cent to the price of each litre of soft drinks, alcoholic beverages, and bottled water and have money left over.

I would draw your attention to the difference between mathematics and reality. Although mathematics is extremely useful in modeling reality, it's important to remember that while all models are wrong, some are nonetheless useful.

Thus, a household gardener or storage tank owner or a builder of small boats can choose the appropriate diameter of hose, tank, or pontoon very effectively by rounding PI to 3 but cannot do so when "rounding" to 1 or 5. In these cases, it literally doesn't matter how many decimal points you use, because the difference between 3 and any arbitrary decimal expansion of PI will be too small to have concrete meaning in actual use.

Under the philosophy you are promoting, it would be impossible to act in the physical world whenever it throws an irrational number at us.

I don't know, but I suspect that there is a whole branch of mathematics, engineering, or philosophy that describes what kinds of simplifications and rounding are acceptable when choosing to act in the physical world.

The real world in which we act has a fuzziness about it. I think it's better to embrace it and find ways to work with that than to argue problems that literally have no numerical solution, at least when those arguments would have the effect of making it impossible to act.

There was a recent post asking what the self-taught among us feel we are missing from our knowledge base. For me, it's being able to calculate stuff like that for making decisions. I feel like I can spot an equivalence to the travelling salesman problem or to the halting problem a mile away, but anything more subtle is beyond me.

Of course, in this situation, I'd probably just see if I could find a sufficiently large precalculation and just pretend :)

Not necessarily. Calculating the flotation of a cylindrical pontoon using pi=5 will leave you with a boat that sinks!

I was not worried about banks at all. Not even a bit. It just seemed too much to hope for that they couldn't get their collective heads around my 25-year mortgage. That mortgage meant that I had negative net worth, so I was actually hoping they'd screw up. Yes, I knew they had paper copies kicking around, but paper gets lost with frightening frequency.

I was a freelance programmer at the time. My main focus was on making sure that none of my contracts left me on the hook for anything Y2K related that wasn't explicitly contracted for.