[Confusion]

Then blacksmiths in the Middle Ages did not 'understand' the forging of swords. Only modern materials science allowed us to 'understand' why forging creates harder metal.

This is a semantic discussion about the meaning of 'understanding': does it mean you can globally explain how the system works and could come to understand the smallest detail of every part? Or does it mean you understand the smallest detail of every part?

The latter is a nonsensical definition: if that is the case, then nobody understands processors, because nobody understands transistors, because nobody understands quantum mechanics, because nobody understands why the fundamental forces act in certain ways. Nobody understands Newton's laws, nobody understands where babies come from and nobody understands what it means to perform a 'computation'[1].

Of course, that means the former was also a nonsensical defintion.

[1] http://plato.stanford.edu/entries/church-turing/

[JackC]

> Then blacksmiths in the Middle Ages did not 'understand' the forging of swords. Only modern materials science allowed us to 'understand' why forging creates harder metal.

The interesting way to construe the article's claim is not that it's impossible to know everything, but that's impossible to know everything that people already know about the field you work in.

Were there blacksmiths who knew everything anyone knew about forging swords? Did Newton or Da Vinci know everything anyone knew about the various fields they were expert in? Are there farmers now who know everything anyone knows about how farming works? The article claims that at some point it became a certainty that programmers cannot know everything that anyone knows about how to use the tools they use and what those tools do. The stack is too complex. That's at least a sensible and interesting claim.

[Confusion]

No blacksmith, farmer or famous scientist/artist/Renaissance man in history has ever known everything there was to know (about the field they worked in). Even back then, there was already more knowledge being produced than they could possibly ever obtain. As with us, the ultimate problem is a lack of time. Whether the time required to travel to a neighbouring city to learn from their guild or the time required to read a paper on the internet, the problem is time.

All stacks have always been too complex. A farmer, to produce optimally, has to understand everything there is to know about meteorology, biology, sociology, economics and earth sciences concerning his specific area. That has never been the case.

In that sense of 'understand', nobody has ever completely understood any system they worked with/in. Given a system and a person, you can come up with a legitimate detail question about the system that you also believe the person couldn't answer.

[bwarp]

Semantically speaking, understanding is simply knowing enough to recreate something, preferably with your own aquired skills and knowledge. We're all just fancy parrots wrapped up in monkey bodies.

To be honest, the bedrock abstraction should stop at "what humans can realistically create with their own hands from nothing". You can make your own transistor quite easily and Ebers-Moll provides a nice set of rules to work with.

The quantum physicists and philosophers can remain arguing about technicalities then and let the rest of the world observe, understand and create.

[andylei]

> what humans can realistically create with their own hands from nothing

could medieval blacksmiths really create a sword from nothing but their own hands? how would they get the iron? would they have the knowledge locate veins of iron and then mine that iron? could they build the kiln and forge the equipment necessary for forging

arguably, by this standard, even farmers could not farm. farmers may know how to plant their crops, but without current crops to gather seeds from, would they know how to find the strains of plants that suit farming and then gather the seeds from those plants?

[bwarp]

Well actually, I reckon yes. Much to my parents' latent terror (I didn't tell them until they came back from holiday), at the age of 15 a friend and myself built a small blast furnace using some ceramic pots, bits of stone lying around and a hoover. I managed to get 50g of what looked like pig iron out of that bugger before it basically fell to bits and set fire to the lawn. That was from about 2kg of ore I found at the bottom of a cliff face next to a beach at Skegness. Was great fun! (flux was limestone from the shed, coke was 3 large bags of barbeque charcoal)

I'm sure that and the rest of the process wasn't beyond people with a higher budget and requirements...

As for plants - it's all knowledge and experience. There is no abstraction. Eat this, don't eat that. I grow quite a few edible plants myself and there is little abstraction.

[masklinn]

> You can make your own transistor quite easily

Not from scratch no. Not even with all the intermediate knowledge available but none of the tooling and technology. Unless by "quite easily" you mean "in under a dozen generations".

[bwarp]

Rubbish! http://www.southgatearc.org/news/november2010/make_a_transis...

[masklinn]

You're joking right? Taking apart an existing diode to build a transistor from it comes nowhere close to making the transistor from scratch. Not to mention the clamps and files, the microscope, the phosphorous bronze for the contacts, ...

This video is great, but it's a century or two of progress away from "from scratch".