 Member ◆◆ Posts: 274 Joined: Apr 2001 From: exiled from the archaeology forums |
#1▸ Posted: 13 Nov 1995, 09:12 MST
I have been reading about the Great Pyramid's dimensions again, and there is a claim I keep seeing: divide the perimeter by twice the height and you get something very close to pi. The obvious explanation is that the Egyptians deliberately encoded pi into the monument. But I am skeptical.
A few questions for the board. First, how precisely do we know these dimensions -- are we measuring from original casing stones, or reconstructing from what is left? Second, if deliberate, why express it this way, perimeter over twice the height, rather than something more direct? Third, and most important: how many ratios could we extract from a pyramid's dimensions, and how many would be close to a famous constant just by chance? I am not saying the Egyptians were unsophisticated. I am asking whether we are pattern-matching, or whether this tells us something real.
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 Member ◆◆ Posts: 61 Joined: Nov 1997 From: Minneapolis, MN |
#2▸ Posted: 14 Nov 1995, 21:21 MST
opus_reticulatum, right question, but I need numbers before I engage. What dimensions are you using, with what error margins, and which survey -- Petrie's from the 1880s or something more recent? Petrie's measurements have known uncertainty bands. If the "pi match" only works when you pick one measurement over another or round a particular way, that is not encoding -- that is just how close things happen to be.
Quick arithmetic on the common figures: perimeter roughly 920 meters, height roughly 146 meters, so perimeter over twice the height is about 3.15. Close to pi. But "close" is doing a lot of work. What is the tolerance? Give me the actual data and I will stop being skeptical.
statistics matter |
 Member ◆◆ Posts: 73 Joined: Nov 1997 From: UK |
#3▸ Posted: 16 Nov 1995, 09:30 MST
This is the cherry-picking problem, stated plainly. The Great Pyramid is enormous -- a perimeter, a height, a diagonal, a slope angle, internal passages. If you combine those measurements every which way, you generate dozens of ratios. Now, how many mathematical constants do we care about -- pi, phi, e, root two, a handful? The probability that none of those dozens of ratios lands near one of those constants by chance is low. You are guaranteed matches if you look hard enough.
The real question is which ratio the Egyptians thought was important and whether they built it in deliberately. If you cannot answer that from the architectural record or the papyri, you are data-mining, not decoding.
the real risk |
 Member ◆◆◆ Posts: 612 Joined: Sep 2001 From: Durham, UK |
#4▸ Posted: 17 Nov 1995, 21:39 MST
I think the pi ratio might not be design at all -- it might be an artifact of measurement method. Suppose they measured horizontal distance by rolling a cylindrical drum: the circumference encodes pi directly, since each roll covers pi times the diameter. Now suppose they measured height in cubits with a rod and plumb. Divide a wheel-measured distance by a cubit-measured height and, depending on calibration, you naturally get something near pi as an output of the method, not an intentional encoding. This is the kind of thing that happens in metrology -- a ratio looks "magical" because it is baked into your tools. I do not know enough about the specific Old Kingdom practice to confirm it, but it is worth checking before assuming design.
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 Member ◆◆◆ Posts: 176 Joined: Feb 1996 From: Norway |
#5▸ Posted: 19 Nov 1995, 09:48 MST
I want to bring in the seked, because I think it is the key. The seked is the slope ratio the Egyptians used -- the horizontal run per cubit of vertical rise. The Great Pyramid has a seked of about 5.5 palms per cubit, a palm being a seventh of a cubit. That is a practical slope, easy to set out: up a cubit, over 5.5 palms, giving a face angle around 51.5 degrees. It is not chosen for any abstract property. It just works.
But when you work backward from that practical slope and the dimensions it requires, the perimeter-to-height relationship falls out as a side effect. The pyramid shape itself generates the appearance of pi-encoding because the seked was chosen for practical reasons. DrMarlow is onto something -- it is a byproduct of method and practical geometry, not an encoded constant.
slope ratios |
 Member ◆◆ Posts: 640 Joined: Oct 2000 From: New York, US |
#6▸ Posted: 20 Nov 1995, 21:57 MST
I understand the cherry-picking and measurement-method arguments, but they feel like bending over backwards to avoid the obvious. The agreement is remarkable -- not "loosely similar to pi" but very close, depending on which surveyors you trust. That does not happen by accident.
And the seked argument does not explain why that particular seked produces a ratio so close to pi. You call it coincidence, but coincidences have probabilities, and this one feels past the tail. The Egyptians were mathematicians. The precision of the construction suggests deep intentionality. Why is it so hard to believe they encoded pi -- not as our abstract symbol, but as a property of the circle they understood through practical geometry?
intention matters |
 Member ◆◆ Posts: 57 Joined: Mar 1996 From: Poland |
#7▸ Posted: 22 Nov 1995, 10:06 MST
gematria_Gita, I respect the position, but you are conflating mathematical sophistication with knowledge of pi as an abstract constant. The Egyptians were superb practical mathematicians -- right angles, land division, areas. That is not the same as needing an abstract pi. You do not need pi to build a beautiful pyramid; you need geometry, proportion, and careful surveying.
The seked works. It produces stable, harmonious proportions, and those proportions happen to relate to pi because pi relates to slopes and circles. The builders were not thinking "encode the ratio of circumference to diameter." They were thinking "what slope is stable, beautiful, and within the tolerance of my tools?" Occam's razor cuts toward the byproduct, not the encoding.
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 Member ◆◆ Posts: 274 Joined: Apr 2001 From: exiled from the archaeology forums |
#8▸ Posted: 23 Nov 1995, 22:16 MST
Thanks to everyone who engaged seriously. The data is the crux -- Dan_Sorensen is right to want error bars before claiming a match. Deborah_Q's cherry-picking point is sobering and underrated. And DrMarlow, Halvorsen, and Tomasz_K have laid out a coherent alternative that needs no mysticism: the pi ratio emerges from practical choices about slope and measurement, not intentional encoding.
gematria_Gita, I understand the appeal of your reading, but I am convinced the "remarkable precision" may be a selection effect -- which measurements you pick and how you round. The Great Pyramid is a remarkable achievement of practical geometry and engineering, and that is plenty remarkable without an encoded constant. I will be looking for the actual survey data and the papyri; that is where the real story is.
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