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mx7zysuj4xew | 1 month ago

My own favorite example of this is how the pyramids (and all the advanced trigonometry required) were built by the Egyptians prior to their discovery of the wheel

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WalterBright|1 month ago

> advanced trigonometry

There's a ratio involving pi between the base lengths of the pyramid and its height. This is been interpreted by enthusiasts that the Egyptians knew about pi.

But, consider a measuring wheel, where you can mark off distances very accurately by counting revolutions of the wheel, say, 1 cubit in diameter (I know, I know, what's a cubit?). Then, if the height is laid out in cubits, the ratio of pi is there while being completely ignorant of it.

pantalaimon|1 month ago

> This is been interpreted by enthusiasts that the Egyptians knew about pi.

Well if you want to calculate the circumference of earth and know the distance between Alexandria and Syene, where the sun casts no shadow at noon during the summer solstice, you also need to know pi.

dmurray|1 month ago

But that doesn't explain things if it's true that they hadn't discovered the wheel!

jdougan|1 month ago

> what's a cubit?

What's an ark?

orwin|1 month ago

Discovery of the axles and roads.

The 'wheel' itself was discovered everywhere. Round things are easier to move, but you need an axle to make it useful. And roads or flat terrain to make use of that. Incas had pulley systems, which indicates they could probably have built an axle quite easily too, but had no use for it, because, well, no flat roads.

And even then Northern Manchurians knew about the wheel for sure, and knew about roads, but still used sleds until at least the Russian conquest.

Sorry, I'm quite boring about this, but it bothers me when people talk about 'inventing the wheel' like it was something special. The wheel itself is meh. The axles are what makes it usable, and the roads make it useful.

jeltz|1 month ago

Roads were also innvented everywhere. There were cultures with flat roads and no wagons. I would say the axle and then the spoked wheel were likely the big deals.