> For instance, is claim that the use of wheels for transportation is in some way gated by the availability of pack animals. This guy has never used a wheel barrow I guess...
I pulled up a PDF of GG&S to search through and I can't see this argument in the book. What I can see is him making the observation that the wheels invented in mesoamerica didn't make their way north or south to be paired up with pack animals, and that this showed how hard it was for technological discoveries to travel vertically through climates.
He argues that because technology transfer was difficult in the Americas, the ancient Mexican wheel never found it's way to the Andes where it may have been combined with suitable pack animals. That much is fairly plausible. But he goes further than this: he also argues that because ancient Mexican wheels weren't combined with pack animals, wheels could offer no practical utility to ancient Mexicans and this explains why the wheel wasn't put to practical use in the Americas. This is too far, he's forcing the data to fit his model.
The relevant passage:
> While wheels are very useful in modern industrial societies, that has not been so in some other societies. Ancient Native Mexicans invented wheeled vehicles with axles for use as toys, but not for transport. That seems incredible to us, until we reflect that ancient Mexicans lacked domestic animals to hitch to their wheeled vehicles, which therefore offered no advantage over human porters.
It has nothing to do with pack animals. Pack animals are not and never were a prerequisite for putting wheels to practical use. Across all of humanity, perhaps as few as two individual people ever had the idea to invent the wheel; at least once in China and at least once again in Mexico; all other uses of the wheel plausibly descent from these two instances of invention. So obviously the wheel wasn't an obvious invention, and neither were practical applications for the wheel obvious, except seemingly so in retrospect. Chariots appeared about 4000 years ago, but wheel barrows only appeared about 2000 years ago. You can't explain that gap with environmental circumstances. The gap is explained when you realize these aren't obvious inventions. Searching for environmental reasons for the invention or non-invention of such things is folly, because the greatest hurdle to clear is simply having the incredible luck of somebody on your continent having such an idea in the first place.
Your claim that perhaps as few as two individuals in all of history thought of the wheel seems far-fetched, and presented without evidence. You aren't even addressing Diamond's argument. Diamond doesn't claim that the wheel only got invented twice or a few times in history. He asks why the ancient Mexicans apparently didn't use wheels for transport, and why the invention of the wheel didn't get transported south or north to other civilizations.
Very few wooden artifacts from prehistory or ancient times survive, and we know about ancient chariots and carts from depictions in art rather than from surviving examples. Lacking animals to pull wheeled carts leaves people to carry stuff, and then you have to ask if people using wheelbarrows or pulling wheeled carts makes transporting goods more efficient than having more people carry stuff. And you have to ask if the civilizations who didn't use wheels had access to the materials (hard wood) to make wheels and axles and carts. Any number of factors might have affected the adoption of wheeled vehicles, or failure to go that direction, but positing that the wheel idea only came up a handful of times in a couple of places seems an unlikely explanation.
The precursor to wheels is fairly obvious and doesn't require one brilliant mind out of millions. Logs used to roll heavy loads were used by probably every neolithic culture that built monuments, including those that never developed wheeled vehicles pulled by animals. Going from there to the wheel doesn't seem like a huge leap of insight.
Across Eurasia you had about 2000 years where people were riding around on chariots with strong spoked wheels, but farms didn't have even primitive wheelbarrows to move rocks off their fields. Moving rocks off fields is back breaking work and even a primitive improvised wheel barrow gives you an order of magnitude advantage. The prerequisite technology, conditions, demand, etc were there, but it took thousands of years for somebody to have the idea. Therefore, I think it's safe to conclude that very few people who've never seen or heard of a wheelbarrow would ever have the idea to invent one, even if they were already familiar with wheels in other contexts. The idea itself is the rare thing, not the prerequisite technological/social conditions. The idea can go unhad for thousands of years after all the other pieces were in place.
> You aren't even addressing Diamond's argument.
I think Jared Diamond could be correct, but I would still say that his argument is lame because he failed to establish a high likelihood of prompt invention once prerequisite conditions are met before concluding what those supposedly missing prerequisites were. I'm not addressing his argument because he failed to convince me that his argument addresses a real question in the first place. Supposing hypothetically that ancient Mexico had pack animals, it still might have been thousands of years before pack animals and wheels were put together.
> Going from [rollers] to the wheel doesn't seem like a huge leap of insight.
I really think it was. There's a big conceptual gap between rolling something on logs, and making the rollers captive through the use of an axle. The roller goes from being a tool used to move a thing to being an integral part of the thing. Wheels may have been invented more than twice, but there's not much evidence for that. And in any case, it certainly did take a very long time for some seemingly simple applications of wheels to be considered after wheels were popularized for more sophisticated and demanding purposes.
Why do you think ancient farmers cleared fields of rocks to plant or graze? They didn't have machinery that would break. Farms were small. They could just avoid or work around large rocks, and throw the smaller ones to the side to make walls or rock piles. The plow was invented long after agriculture began, and a plow pushed or pulled at human or ox speed wouldn't break on a rock. I agree that moving lots of heavy rocks off of fields would be back-breaking labor, but why would ancient farmers choose such sites to plant? Just because modern farmers clear fields to open up more land to farm doesn't mean ancient farmers had to do that -- they could plant and harvest where the wild grasses already grew.
I don't know why the wheelbarrow turns up so late in history. Perhaps they were made entirely of wood, left no artifacts to find, and were common and unremarkable so don't show up in art or monuments. We don't find many spears for the same reason, only the spear tips. Wood gets recycled, burnt, and decays.
It's an interesting question but since people invented spoked wheels and chariots quite a long time ago I don't think no one ever thought of making carts or wheelbarrows.
I pulled up a PDF of GG&S to search through and I can't see this argument in the book. What I can see is him making the observation that the wheels invented in mesoamerica didn't make their way north or south to be paired up with pack animals, and that this showed how hard it was for technological discoveries to travel vertically through climates.