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Author Topic:   Assumptions involved in scientific dating
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 1 of 222 (789072)
08-10-2016 10:50 AM


In the flood thread we have the following:
Coyote writes:
And what scientific evidence would you use to dispute the time frame?
ICANT writes:
The assumptions you have to use to begin with.
I would like to use radiocarbon dating as the main subject, as that's the one I'm most familiar with.
The primary assumption in radiocarbon dating that all organisms contained the same amount of C14 when they died. As atmospheric levels of C14 vary with cosmic radiation, and initial amounts of C14 can vary by a few percent, we need to calibrate our dates, and this is done quite successfully via tree-rings, varves and other annular data.
Another assumption is that the decay constant is and has been constant. There's no evidence to show that this is not correct.
And those seem to be all of the important assumptions!
I've seen creationists' lists with up to nine assumptions that they argue make radioactive dating inaccurate, but for radiocarbon dating those are the main assumptions we rely on.
Now, the job for ICANT and other creationists is to show that these assumptions lead to huge errors in radiocarbon dating. Simple denial is not good enough.
A good basic reference for those who are not yet familiar with the subject:
Answers to Creationist Attacks on Carbon-14 Dating

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

Replies to this message:
 Message 3 by NosyNed, posted 08-10-2016 11:38 AM Coyote has replied
 Message 7 by kbertsche, posted 08-11-2016 3:41 AM Coyote has replied
 Message 61 by DOCJ, posted 01-21-2018 3:46 AM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 4 of 222 (789081)
08-10-2016 11:49 AM
Reply to: Message 3 by NosyNed
08-10-2016 11:38 AM


Assumptions are not wild guesses
Is this really an "assumption"? Is it still an assumption when it has been tested and verified to a very high degree?
Creationists imply that the assumptions they don't like are nothing more than wild guesses.
You are correct that this assumption has been tested and verified many times. That's the case for the majority of assumptions used in science. Most assumptions are far from "wild guesses."

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 3 by NosyNed, posted 08-10-2016 11:38 AM NosyNed has not replied

Replies to this message:
 Message 39 by ICANT, posted 02-06-2017 3:22 AM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 8 of 222 (789135)
08-11-2016 9:23 AM
Reply to: Message 7 by kbertsche
08-11-2016 3:41 AM


I'm still waiting for ICANT or some other creationist to enlighten us on which assumptions they are having problems with.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 7 by kbertsche, posted 08-11-2016 3:41 AM kbertsche has not replied

Replies to this message:
 Message 9 by NoNukes, posted 08-11-2016 9:58 AM Coyote has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


(3)
Message 10 of 222 (790780)
09-05-2016 8:50 AM


Creationists have been very silent on assumptions
This thread, for creationists to document why the assumptions used in radiometric dating are unfounded, has been open nearly a month.
In spite of all the creationist claims we see that radiometric dating is invalid because "assumptions," not one creationist has been willing to post their claims in detail here.
So much for their claims...

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

Replies to this message:
 Message 11 by Pressie, posted 09-07-2016 8:25 AM Coyote has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 14 of 222 (790905)
09-07-2016 6:16 PM
Reply to: Message 13 by Faith
09-07-2016 5:05 PM


Re: Creationists have been very silent on assumptions
Relative dating is not the subject of the thread.
Have you any observations on the assumptions involved in scientific dating?

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 13 by Faith, posted 09-07-2016 5:05 PM Faith has replied

Replies to this message:
 Message 15 by Faith, posted 09-07-2016 6:31 PM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 17 of 222 (790914)
09-07-2016 9:26 PM
Reply to: Message 15 by Faith
09-07-2016 6:31 PM


Re: Creationists have been very silent on assumptions
Faith writes:
Coyote writes:
Relative dating is not the subject of the thread.
Have you any observations on the assumptions involved in scientific dating?
Sure: absolute or "scientific" dating is irrelevant if relative dating is all it takes to find oil or do other practical geological work.
You and other creationists have challenged radiometric dating based on "assumptions."
Here's your chance to present your evidence.
Leave relative dating for another thread.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 15 by Faith, posted 09-07-2016 6:31 PM Faith has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 19 of 222 (790920)
09-07-2016 11:42 PM
Reply to: Message 18 by Faith
09-07-2016 11:16 PM


Re: Creationists have been very silent on assumptions
Please, tell us how the assumptions involved in scientific radiometric dating are incorrect.
Don't get sidetracked. I know its easy to do, but this thread is for a specific purpose and I'd really appreciate your input on the OP.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 18 by Faith, posted 09-07-2016 11:16 PM Faith has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


(2)
Message 25 of 222 (791644)
09-19-2016 2:55 PM


Bump for creationist input
This thread has been open for about six weeks, and still no posts by creationists detailing why they think the assumptions used by radiometric dating, and particularly by radiocarbon dating, invalidate the results.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

Replies to this message:
 Message 26 by Pressie, posted 09-20-2016 6:57 AM Coyote has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


(2)
Message 28 of 222 (791741)
09-20-2016 4:35 PM
Reply to: Message 27 by Taq
09-20-2016 2:52 PM


Re: Devil's Advocate
Contamination is indeed a problem in C14 dating.
Small rootlets in a charcoal sample can make it date too young.
Marine shell has to be corrected for deep water upwelling, and a lot of research has gone into establishing the amount of upwelling for different parts of the world.
Freshwater shell is also a problem if fed by water sources rich in dissolved limestone--they will date way too old.
One way of determining how good your sample is is the C13 reading. Clean charcoal should have a reading somewhere close to —25 (don't worry about what the number means at this point). Good marine shell should be somewhere around 0 or 1.
Bone should be somewhere around —22 unless it is marine mammal bone, then expect something around —14. (You'd be surprised how many archaeologists submit a piece of unidentified bone and get a C13 reading around —14 and treat it as terrestrial bone. Their date is likely off by about 500 years, as marine mammal bone needs a correction for deep water upwelling.)
If you get a C13 reading that differs greatly from the normal figure for that material, better cross-check the results with additional samples. You should never do just one sample anyway!
Laboratories will do a good pretreatment on the samples and this catches most contamination. For shell, the will treat it with a weak acid and dissolve away a decent percentage of the sample to get rid of the soft outer layers, leaving good dense shell for the sample. Charcoal is pretreated in a variety of ways to get rid of modern organics like rootlets.
And you're right--sample selection is very important. In addition to contamination there are a lot of sources of bias in sample selection. Multiple pieces of shell from a midden will result in a "homogenized" date. You need to date single pieces of shell. Another problem we've noted: prehistoric inhabitants changed and improved their technologies and subsistence/settlement systems over time. In the area I work the most, the oldest dated abalone shell is about 5900 years old, while the oldest mussel shell is over 9400 years old (this is out of about 500 samples, so its a good universe). What this means though is 1) the prehistoric inhabitants didn't make much use of abalones early on, and 2) if archaeologists date just abalone shells they'll miss some 3500 years of early prehistory.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 27 by Taq, posted 09-20-2016 2:52 PM Taq has replied

Replies to this message:
 Message 29 by Taq, posted 09-21-2016 11:47 AM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 31 of 222 (791791)
09-21-2016 4:43 PM
Reply to: Message 29 by Taq
09-21-2016 11:47 AM


Re: Devil's Advocate
I suspect that this is due to both carbon source and fractionation during photosynthesis. Photosynthesis favors lighter isotopes, so I suspect that the 13C values you are giving are probably related to 13C/12C ratios. In terrestrial ecosystems, photosynthesizers fix carbon, and that carbon then filters down through each trophic level.
Is this not also the case with aquatic environments? I wouldn't be surprised if free 13C/12C ratios were different for aquatic environments, but do marine animals fix dissolve carbon dioxide instead of deriving it from photosynthesizers? Or is the dissolved CO2 in aquatic environments just that different?
Isotopic fractionation is indeed what causes these differences in the C12/C13 ratios. A text and table showing these types of differences are located at:
Isotopic Fractionation
Isotopic fractionation.
I believe marine mammals pick up the C12/C13 ratios from their diet, as so terrestrial mammals.
Short on time at the moment, more later if you want.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 29 by Taq, posted 09-21-2016 11:47 AM Taq has not replied

Replies to this message:
 Message 33 by kbertsche, posted 09-21-2016 9:09 PM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 32 of 222 (791792)
09-21-2016 4:44 PM
Reply to: Message 30 by Faith
09-21-2016 4:12 PM


Re: Maybe off topic
Faith--I'd rather keep this thread to dating issues if possible.
That's one of my main interests and areas of expertise.
Thanks!

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 30 by Faith, posted 09-21-2016 4:12 PM Faith has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 34 of 222 (791887)
09-25-2016 11:00 PM
Reply to: Message 33 by kbertsche
09-21-2016 9:09 PM


Re: Devil's Advocate
I looked it up and you are correct, corn gives a much higher C13 reading than other similar plant materials. I had not been aware of that as we don't have corn in our local prehistoric sites so I had never had cause to date that material.
I don't know the cause or name for the process, but its good to know if I ever want to date that material.
I most often date marine shell, which has a good track record in this area. On one occasion I dated charcoal and two different shell species from a very tight provenience and after marine reservoir correction and calibration ended up with three dates within 10 or 15 years or some such. That's pretty good!

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 33 by kbertsche, posted 09-21-2016 9:09 PM kbertsche has not replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


(2)
Message 37 of 222 (798798)
02-05-2017 2:49 PM


Bump (again) for creationist input
Creationists are still ignoring this thread.
This is their big chance to present evidence!

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 41 of 222 (798888)
02-06-2017 9:54 AM
Reply to: Message 39 by ICANT
02-06-2017 3:22 AM


Re: Assumptions are not wild guesses
Please stick to the original subject of scientific dating, particularly radiocarbon dating.

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 39 by ICANT, posted 02-06-2017 3:22 AM ICANT has replied

Replies to this message:
 Message 42 by ICANT, posted 02-06-2017 1:32 PM Coyote has replied

  
Coyote
Member (Idle past 2096 days)
Posts: 6117
Joined: 01-12-2008


Message 45 of 222 (798921)
02-06-2017 2:37 PM
Reply to: Message 42 by ICANT
02-06-2017 1:32 PM


Re: Assumptions are not wild guesses
The first assumption you have to make is that the universe is x years old, A constant rate of decay, an isolated system in which no parent or daughter element can be added or lost, and a known amount of the daughter element present initially.
We're not dealing with rocks--radiocarbon dating works with carbon! Most of your "objections" deal with radiometric rather than radiocarbon dating. You should learn the differences!
A constant decay rate is a good assumption, well supported by the evidence. Only a few creationists disagree based entirely on non-scientific beliefs.
We can test for atmospheric radiocarbon via tree-ring dating so the parent/daughter argument does not apply.
Creationists just don't like the results of radiocarbon dating and so they're casting about aimlessly for any plausible-sounding excuses so they don't have to accept those results.
Here is a good website from which you might learn something:
Radiometric Dating: A Christian Perspective, by Dr. Roger C. Wiens
Radiometric Dating

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
Belief gets in the way of learning--Robert A. Heinlein
In the name of diversity, college student demands to be kept in ignorance of the culture that made diversity a value--StultisTheFool
It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers
If I am entitled to something, someone else is obliged to pay--Jerry Pournelle
If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
"Multiculturalism" demands that the US be tolerant of everything except its own past, culture, traditions, and identity.

This message is a reply to:
 Message 42 by ICANT, posted 02-06-2017 1:32 PM ICANT has not replied

Replies to this message:
 Message 48 by JonF, posted 02-06-2017 5:41 PM Coyote has seen this message but not replied

  
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