[jbay808]

You're probably joking, but since "it's just survivor bias" is a popular take these days, I'll respond as though you're serious.

A bridge that stands for 2000 years without (much) maintenance isn't survivor bias, it's disruptive technology.

Yes, we only see the best of Roman architecture, and most Romans probably lived in wooden shacks or stone apartments that have long since crumbled or been demolished.

But Roman concrete is chemically different than the Portland cement that was invented in the 1800s, and although there's certainly a distribution of building quality and workmanship that will result in a wide spread of lifetimes, we don't have any reason to expect that any concrete building built from Portland cement and exposed to the elements like Roman seawalls were will last 2,000 years. The distribution just doesn't have that long of a tail to it.

[joshspankit]

An important component to the survivor bias argument in this case is: we have no way of knowing what roman concrete didn’t survive. Maybe the ones standing are atypical, or were in some way a fluke as opposed to the marvel they seem to be.

[jbay808]

Sure, but that's also not really the point.

When we see these structures standing, our reaction should be "wow! How did they do that? What can we learn?"

Not "well, I bet they also built a lot of bad buildings too; nothing to see here".

When you build something twice as good as the average, it's a fluke. When you build something 20x as good as average, it's worthy of study. Even if these are atypically good examples of Roman architecture[1], you can't pull off the moon landings by launching a ton of backyard fireworks and hoping for a long-tailed success distribution.

The best buildings represent the state of the art of the best architects and the best masons working with access to quality materials and an adequate budget and timeline. Not dumb luck and guesswork paying off.

[1] Which there are decent reasons to not expect. For example, we know that many Roman buildings were demolished deliberately by later generations because they weren't Christian enough, rather than because they collapsed.

[shultays]

Sure, surviving for such a long time is a big accomplishment but compared to bridges today, they are relatively short bridges that cost more to build and allows less load. What is there to research other than figuring out how they work? They are well structured blocks of rocks that distributes the load well basically.

How they were built is probably more interesting, but still would be useless

[ricardobeat]

> They are well structured blocks of rocks that distributes the load well basically

So is a building like the Burj Dubai, but this is an incredible understatement of the technology involved. The reason Roman concrete is interesting is that until ~50 years ago we had no idea what made it so durable. Dams are being built using these discoveries, sounds quite useful to me.

[jbay808]

As the article explains, the most interesting thing is their seaworthy cement. Although today's Portland cement is newer, it wasn't adopted because it was superior to Roman cement, but because (until recently?) no living person knew how to make Roman cement.

Hence, we can indeed learn something by studying it.

[darkerside]

It's typically not the case that we can't make things as well as we use to. It's just that we've found ways to make them that are cheaper by an order of magnitude and last just long enough to do their job.

Roman concrete wasn't disruptive. It was disrupted.

[jbay808]

> Roman concrete wasn't disruptive. It was disrupted.

I'm amazed by this mentality. It's like the very possibly of a technology being forgotten, rather than surpassed, is axiomatically impossible.

If "everyone who knew the recipe died" counts as getting disrupted, then yes, it was disrupted. And if Roman concrete counts as more expensive because the supply is literally zero, the yes, modern concrete can be seen as cheaper.

But understand that modern Portland cement wasn't invented to improve on Roman concrete, but rather as an attempt to replicate it, because nobody until then had any guess.

[mikorym]

So maybe the article should have said, "How the Ancient Roman good stuff concrete has survived 2000 years."

[Retric]

We have some ideas. For one thing a reasonable amount of documentation still exists that speaks how things where run.

Rome was not building all that much stuff, they simply didn’t have nearly the population or wealth we do. Think the population of Tanzania and the GDP of Libya spread across as much land as India.

Meanwhile we can see structures like Portus Adurni that are mostly intact. A meaningful percentage of their larger structures are still around.

[Gibbon1]

And after the fall of Rome the economy was smaller and more fragmented.

Last time I looked into this I came away with the observation that preindustrial concrete was very labor intensive. We use it for it's physical properties and because it's 'cheap'. Roman concrete wasn't cheap at all.

The central Roman government was able to marshal the effort necessary to produce it on a ongoing basis for particular uses. But I understand Romans mostly used brick and mortar for ordinary construction.

After the Roman Empire fell apart concrete probably didn't make sense.

[rayiner]

Eh, we kind of do. If the surviving structures were that far off on the long tail distribution, then we could anticipate that there were truly massive amounts of concrete structures in existence before. And we can tell from other things we know about Rome whether that was the case (it’s not).

[petre]

We still use Roman technology or ideas today: double roman roof tiles, underfloor heating, water distribution, paved roads etc. Italian ceramic tiles, stone and adhesives for them are still the best you can get in Europe.

[sokoloff]

ObMontyPython “What have the Romans done for us?” clip:

https://m.youtube.com/watch?v=Y7tvauOJMHo