3 ms·

That was definitely interesting but doesn't feel fully thought out. That's how much energy it takes to move the blocks vertically into their position, ok. Wha

by habosa 6y ago

That was definitely interesting but doesn't feel fully thought out. That's how much energy it takes to move the blocks vertically into their position, ok. What about horizontal movements to bring the blocks from the quarry to a staging area to their final place? Also there doesn't seem to be any consideration of logistics time. Were the 900 men always perfectly positioned to apply their energy to the project? Did they not spend time and energy moving around the building site? Did they ever make a mistake and have to redo a section? This is a good starting estimate. As anyone who's ever worked on any project knows, the estimate is going to be way too optimistic. Also: I've been to Giza. It's hot and dry as all hell. Humans are going to be far from perfect labor machines in that climate.

Balero 6y ago
"Also: I've been to Giza. It's hot and dry as all hell. Humans are going to be far from perfect labor machines in that climate" The climate 4500 years ago was very different in this area, and the world in general. For Egypt and the middle east it was generally a little cooler, but much wetter. When we are looking back into history, even only a couple of hundred years it is important to remember that the climate, and geography was different. Climate shifts, rivers and coastlines move etc.
- close04 6y ago
  The analysis is only about the effort to lift one cubic meter of stone to an arbitrary height a number of times until you reach the mathematical equivalent of a "pyramid's worth", and then divide this by the average human work capacity. That's it. No other theoretical or practical aspect was considered. No friction, no logistics, nothing else. The conclusion is that it took 900 men 20 years to lift one 2.6t cubic meter of stone to a specific height again and again. Does anyone considers this to be realistic for any construction project? Like estimating the Mona Lisa took 5s to paint based on the surface of 0.4 square meters. Or the Sistine Chapel ceiling took a couple of days and a really big brush. The fact that someone with such a CV [0] came up with this for the IEEE page as anything more than an exercise of imagination is very surprising for me. [0] https://spectrum.ieee.org/author/vaclav-smil https://spectrum.ieee.org/author/vaclav-smil
  - scld 6y ago
    Well, the graph in the article says 3600 men for 20 years. 900 to lift the stones 900 to place and finish them (horizontal movement?) 1500 to cut the stone 3300 design/support (logistics?) The details are below the fold.
    - haihaibye 6y ago
      There's no accounting for inefficiencies applying human labor to moving massive stone blocks into a really high pile. Has the author ever done physical labor?
    - close04 6y ago
      I'm talking about the details of the real work. The details of his results are irrelevant since they're built from oversimplified assumptions. I mean the author didn't even include friction in his calculations. Or placing blocks with special shapes in exceptional positions. Or any setbacks, logistics, infrastructure, trial and error, design revisions, human inefficiency, illness, accidents, etc. His calculations just say it probably couldn't have taken less. But more? Just add a few more of those variables that he completely overlooked and the effort easily increases by one order of magnitude. The worst project managers I've met made better assumptions that this author. You make bad assumptions you get bad conclusions. And saying them "with certainty" just makes one sound even more ignorant. Imagine what his calculations would say about La Sagrada Familia. Certainly not 150 years.
    - peeters 6y ago
      Except everything besides the 900 estimate is made up out of thin air as far as the "details" go. The "appeal to simple physics" is useful as far as providing a reasonable lower bound ("it must by conservation of energy have been at least 900 workers"). But that's not the assertion of the author, the assertion is that all greater estimates are overestimates, but provides zero evidence for why.
mc32 6y ago
Yeah I’d like to see them make comparative calculations for things that were built prior to steam power and where we have detailed records to see if these estimates hold up.
credit_guy 6y ago
That's right. Here's a more reasonable estimate that I found on bbc [1] "All archaeologists have their own methods of calculating the number of workers employed at Giza, but most agree that the Great Pyramid was built by approximately 4,000 primary labourers (quarry workers, hauliers and masons). They would have been supported by 16-20,000 secondary workers (ramp builders, tool-makers, mortar mixers and those providing back-up services such as supplying food, clothing and fuel). This gives a total of 20-25,000, labouring for 20 years or more." [1] http://www.bbc.co.uk/history/ancient/egyptians/pyramid_builders_01.shtml http://www.bbc.co.uk/history/ancient/egyptians/pyramid_build...

by habosa 6y ago

Balero 6y ago

"Also: I've been to Giza. It's hot and dry as all hell. Humans are going to be far from perfect labor machines in that climate" The climate 4500 years ago was very different in this area, and the world in general. For Egypt and the middle east it was generally a little cooler, but much wetter. When we are looking back into history, even only a couple of hundred years it is important to remember that the climate, and geography was different. Climate shifts, rivers and coastlines move etc.

close04 6y ago
The analysis is only about the effort to lift one cubic meter of stone to an arbitrary height a number of times until you reach the mathematical equivalent of a "pyramid's worth", and then divide this by the average human work capacity. That's it. No other theoretical or practical aspect was considered. No friction, no logistics, nothing else. The conclusion is that it took 900 men 20 years to lift one 2.6t cubic meter of stone to a specific height again and again. Does anyone considers this to be realistic for any construction project? Like estimating the Mona Lisa took 5s to paint based on the surface of 0.4 square meters. Or the Sistine Chapel ceiling took a couple of days and a really big brush. The fact that someone with such a CV [0] came up with this for the IEEE page as anything more than an exercise of imagination is very surprising for me. [0] https://spectrum.ieee.org/author/vaclav-smil https://spectrum.ieee.org/author/vaclav-smil
- scld 6y ago
  Well, the graph in the article says 3600 men for 20 years. 900 to lift the stones 900 to place and finish them (horizontal movement?) 1500 to cut the stone 3300 design/support (logistics?) The details are below the fold.
  - haihaibye 6y ago
    There's no accounting for inefficiencies applying human labor to moving massive stone blocks into a really high pile. Has the author ever done physical labor?
  - close04 6y ago
    I'm talking about the details of the real work. The details of his results are irrelevant since they're built from oversimplified assumptions. I mean the author didn't even include friction in his calculations. Or placing blocks with special shapes in exceptional positions. Or any setbacks, logistics, infrastructure, trial and error, design revisions, human inefficiency, illness, accidents, etc. His calculations just say it probably couldn't have taken less. But more? Just add a few more of those variables that he completely overlooked and the effort easily increases by one order of magnitude. The worst project managers I've met made better assumptions that this author. You make bad assumptions you get bad conclusions. And saying them "with certainty" just makes one sound even more ignorant. Imagine what his calculations would say about La Sagrada Familia. Certainly not 150 years.
  - peeters 6y ago
    Except everything besides the 900 estimate is made up out of thin air as far as the "details" go. The "appeal to simple physics" is useful as far as providing a reasonable lower bound ("it must by conservation of energy have been at least 900 workers"). But that's not the assertion of the author, the assertion is that all greater estimates are overestimates, but provides zero evidence for why.

mc32 6y ago

Yeah I’d like to see them make comparative calculations for things that were built prior to steam power and where we have detailed records to see if these estimates hold up.

credit_guy 6y ago

That's right. Here's a more reasonable estimate that I found on bbc [1] "All archaeologists have their own methods of calculating the number of workers employed at Giza, but most agree that the Great Pyramid was built by approximately 4,000 primary labourers (quarry workers, hauliers and masons). They would have been supported by 16-20,000 secondary workers (ramp builders, tool-makers, mortar mixers and those providing back-up services such as supplying food, clothing and fuel). This gives a total of 20-25,000, labouring for 20 years or more." [1] http://www.bbc.co.uk/history/ancient/egyptians/pyramid_builders_01.shtml http://www.bbc.co.uk/history/ancient/egyptians/pyramid_build...