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Ishmael
In: Toronto
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| Hatty wrote: | | I'm sure you know the story of how Egyptian Demotic developed from the hieroglyphs, but you may not know that almost exactly the same process happened quite separately and independently with the Maya - i.e. a wholly pictographic set of glyphs that over time became adapted for the encoding of sound. |
I didn't know that. How strange that the Mayans built pyramids too. One could be forgiven for concluding a cultural exchange took place, from which direction is uncertain. |
And as I learned from a documentary I saw last night, on MRI scans of King Tut's mummy, the Egyptians also practiced head-binding, known also in South America.
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Ishmael
In: Toronto
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| berniegreen wrote: | | I am pretty sure I read somewhere that they had dated the Mayan stuff to circa 500AD using carbon dating, tree rings (or whatever they are called) and so on. Why can't they do the same for the Egyptians? |
It's all calibrated against the "known" historical records. Useless garbage.
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| Ishmael wrote: | Well then your example with Wallace and Darwin, which you claimed was "enough to prove your point" (indeed!) was woefully inadequate now, wasn't it?
Please provide then an actual instance where the same innovation has been observed to spontaneously arise from truly independent contexts. |
Oh dear! You still haven't got the point that a shared cultural background is not, and cannot be, by definition, a "single point of origin".
Darwin went to University (firstly Edinburgh to study medicine and then Cambridge to prepare for a career as a clergyman). Wallace never attended university at all.
Darwin originally became interested in Natural History through entomology - beetle collecting to be precise. Wallace was hooked initially by Geology.
After the voyage of the Beagle, Darwin published his Journal (1837?) and became a relatively well-known author. Darwin's book was among several which Wallace read during the late 1830's/early 1840's which urged him to throw up his job and to go exploring, firstly in the Amazon and later in Malaysia.
Darwin first conceived his theory in 1838. He discussed with a select group but refused to publish until he had completed all the necessary research. It is probable that Darwin and Wallace met in 1853 or 54 but not being a confidante Wallace was not made privy to Darwin's research.
In 1857/8 while Wallace was in Malaysia he developed his theory of evolution by natural selection. He prepared a paper and wrote to several people in England about this, including Darwin. This paper plus a paper contributed by Darwin was read at the meeting of the Linneaen Society of London on July 1 1858.
One can say that both men were influenced by ideas current at the time but there is solid documentary evidence that they both developed the concept of gene mutation and natural selection quite independently of each other.
Pray tell me, where do you suppose is the "single point of origin" in this story.
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| Chad wrote: | | Carbon dating (for the historical period) is useless because it is calibrated against the accepted chronology of Ancient Egypt |
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Ishmael
In: Toronto
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| berniegreen wrote: | | Ishmael wrote: | Well then your example with Wallace and Darwin, which you claimed was "enough to prove your point" (indeed!) was woefully inadequate now, wasn't it?
Please provide then an actual instance where the same innovation has been observed to spontaneously arise from truly independent contexts. |
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I am now officially bored.
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Chad
In: Ramsbottom
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| berniegreen wrote: | | Chad wrote: | | Carbon dating (for the historical period) is useless because it is calibrated against the accepted chronology of Ancient Egypt |
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Under laboratory conditions, carbon 14 decays at fairly constant rate (better than ± 1%) but archaeological samples are subject to contamination of various forms, not least background radiation (which isn't constant with time). This leads to intrinsic errors, which for the purpose of dating objects from tens of thousands of years ago are quite acceptable.
But as soon a 'proper scientific' dating method became available everybody wanted to take advantage of it... problem was, for relatively recent samples the errors were simply unacceptable.
To overcome this, the decay curve had to 'corrected' against samples of 'known' age. Unfortunately the oldest available calibration samples were from Ancient Egypt. This means that carbon dating of samples from the historic period take their traceability from the 'established' chronology of Ancient Egypt (together with its intrinsic errors).
To then use carbon dating to date other Egyptian samples, leads to an unacceptable circularity.
The problem doesn't stop there. Any new 'scientific' dating method then has to be 'calibrated' to fall in line with the 'established' radiocarbon dates.
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Mick Harper
Site Admin
In: London
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It is interesting, from an AE poiht of view, that 'operational requirements' have dictated that the former chronological benchmark (Manetho's list-of-pharoahs) used to cross-reference all ancient dates, has now been extended to carbon-dating. There is even an official recalibration table that alters the atomic delay rate to conform with Manetho!. Can you imagine the poor chemists requesting that historians have a Manetho recalibration table to ensure that the Laws of Physics are obeyed?
Hardened cynics will spot that now Ancient History dating has scientific backing from blokes in white coats who know that argon is not the title of a Greek King.
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Hatty
Site Admin
In: Berkshire
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At last someone has given an intelligible and intelligent summary of this clearly crucial dating process. Ta, Chad. Does this mean that all archaeological reports are flawed? And should labels like Bronze or Iron Age be eschewed?
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Mick Harper
Site Admin
In: London
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To anticipate the Great Man, I think he is saying that carbon dating is actually fine for rough dating in the Bronze and Neolithic Age where precise dates are not relevant but ballpark figures are. I think he will go on to say that dates older than c 35,000 are not reliable because of half-life considerations. However he is saying that carbon dating is not to be trusted for Iron Age and onwards ie historical dates, not because the figures are intrinsically bad, but because the chemists have taken as gospel what the historians have told them is the 'real' date of the artefacts they are measuring.
However he, Chad, will go on to say that even so carbon-dating is still useful historically for gross dating, for instance measuring the age of the earliest extant Beowulf manuscript: is it seventeenth century or ninth century?
You never see Chad and me in the same room.
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Chad
In: Ramsbottom
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| You never see Chad and me in the same room. |
I invariably anticipate your arrival.
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Okay! V. interesting.
Could the dates be guessed at with "reasonable accuracy" (or "reasonable inaccuracy", come to that) if a genuinely naive person re-dated the Pyramids et al from basic principles ignoring the "re-calibration"? If so we need a genuinely naive person with sufficient science to come forward.
Having just re-read Chad's explanation, another question occurs to me. How unacceptable/unreliable is the "raw" carbon dating? Is the margin for error/degree of confidence 10's, 100's or 1000's of years?
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Just a small thought. Perhaps Chad should add to his profile the motto "WOT! NO DATES?
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Chad
In: Ramsbottom
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| berniegreen wrote: | | Having just re-read Chad's explanation, another question occurs to me. How unacceptable/unreliable is the "raw" carbon dating? Is the margin for error/degree of confidence 10's, 100's or 1000's of years? |
Good question. Some (such as Fomenko) would suggest it is no better than ± two thousand years (I might have used that figure myself in a previous, more sceptical post) and there is some evidence to back this up. When identical, unidentified samples, of fairly recent origin, have been sent to a number of different laboratories, the range of results returned, has had that sort of spread. But if the exercise is repeated with other samples (the nature of which has been revealed beforehand) the distribution of results is invariably much closer to the expected nominal!
I do though, think this may be over-egging the pudding a little, my best guesstimate for raw carbon dates would be an uncertainty of ±(10%+500yrs). Corrected dates older than about 1000 years may actually be even worse, but for the period covering the last 800 years they should be more reliable because calibration samples from this period can be verified against dendrochronology.
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Chad
In: Ramsbottom
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| berniegreen wrote: | | Just a small thought. Perhaps Chad should add to his profile the motto "WOT! NO DATES? |
Yes... I may resurrect my old avatar with that slight modification.
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Grant
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| How unacceptable/unreliable is the "raw" carbon dating? Is the margin for error/degree of confidence 10's, 100's or 1000's of years? |
If you read the Creationist web sites they often quote the carbon dating results from mammoths. Apparently, the age of one foot is sometimes thousands of years different from the age of another part of the body. The pro-Darwin websites claim that's because the raw dates have to be adjusted to allow for contamination by soil etc.
I wonder how many dates are simply ignored because they appear to be obviously wrong?
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