<p>First modern carbon dating does not assume constant Carbon isotope ratios, in fact it is calibrated against known changes in atmospheric concentration, and has been since the 90's. These <a href="https://books.google.com/books/about/Radiocarbon_Dating.html?id=SjsSugCVvC0C&amp;source=kp_book_description" rel="nofollow noreferrer">baselines</a> were created using annular tree rings which of course reflect the atmospheric carbon when each ring was grown as well as ice core data. This was an issue with the earliest forms of carbon dating (and carbon dating alone) which is why they tended to have huge error bars. Using this as an argument against modern dating is like complaining that automobiles are unsafe because they lack doors or windscreens, it shows the person has not kept up with the development of the technology. Especially considering even the wiki for carbon dating addresses the issue at length, so it is likely willful ignorance. </p>

<p>Second dating method are checked against each other, using things like tree rings, stratigraphy, fission tracks, etc. The are also checked against multiple samples. If multiple samples from multiple dating methods arrive at similar dates that is very good evidence of accuracy. </p>

<p>Other radiometric dating method don't rely on ambient conditions just basic chemistry so this is a non-issue. If you want to know more about them I suggest you ask a separate question or review the several existing answered questions about them.  </p>

CC BY-SA 4.0
2019-07-13T21:14:49.983Z
2019-07-15T05:24:40.560Z
2019-07-15T05:24:40.560Z
John
<p>It's very important to realize that Carbon-14 dating cannot be used to date anything older than 100,000 years, even with the most advanced technology we have today. The half-life is not long enough for traces (i.e. measurable amounts) to last that long. So it's a misnomer to think that Carbon-14 dating is responsible for dating rocks, fossils, etc. beyond that time frame.</p>
<p>Instead, other radiometric methods like Potassium-Argon dating are used, which have much longer half lives. Even with these methods, however, we must remember the concept that we can't &quot;measure&quot; age. It's not a physical property we can observe like mass or volume. The concept behind these methods is to measure current decay rate, and work back from the present proportion of decay elements to find the assumed starting point. We do have to rely on the assumption that decay rates have been concept, that we can accurately estimate the starting element, and that it's been a closed system for the entire time.</p>
<p>So yes, even the most &quot;conclusive&quot; dating methods rely on assumptions. There's no way around it. There is even good reason to reject these assumptions on occasion. For instance, Mt. Saint Helens gave us rocks with known ages because of observation, which we saw to have much larger proportions of decay elements than we typically assume, leading dating methods to date them at millions of years old when in reality they were less than 50 years old.</p>

CC BY-SA 4.0
2023-03-15T23:26:32.003Z
Is that last sentence really accurate?  I looked for information about it and found a bunch of stuff about a young earth creationist sending samples from Mt. St. Helens, and eventually a couple of things by actual geologists explaining why the results were wrong - specifically that the lab's equipment was unable to accurately date anything under 2 million years old.
Mark
CC BY-SA 4.0
2023-03-15T15:12:41.133Z
2023-03-15T15:12:41.133Z
Ben Coleman
<p><a href="https://benpiper.com/2011/07/the-truth-about-carbon-dating/" rel="nofollow noreferrer">https://benpiper.com/2011/07/the-truth-about-carbon-dating/</a></p>

<p>The site above explains that Carbon-14 dating is based on a few assumptions, like to deduce the age of an organism by looking at the amount of Carbon-14 left in it and calculating its age based on the time it should have taken for the missing Carbon-14 to decay. However, these assumptions our wrong because the ratio of Carbon-12 to Carbon-14 in the atmosphere has not remained constant and scientists are not able to know. It also states that other radiometric dating methods have similar problems and that these dating methods should be taken with a grain of salt. Is it true that is all assumption and how can we believe these dates?</p>

CC BY-SA 4.0
2019-07-13T17:29:34.250Z
Looking at the books, papers published & the training videos on the author's website, it is obvious his "expertise" is in the fields of architecture & information technology (computers), not radiation dating techniques, such as Carbon-14. He is not professionally qualified to give authoritative comments about Carbon-14 or any other form of radiation dating method.
Fred
CC BY-SA 4.0
2019-07-13T20:43:27.733Z
All science is based on assumptions the only question is whether those assumptions are well supported. Other radiometric dating methods are already answered in other questions like this please ask it as a separate question if you find them unacceptable. https://earthscience.stackexchange.com/questions/864/how-can-scientists-be-confident-of-isotope-ratios-in-past-eras-and-varied-locati
John
<radioactivity>
Is radiocarbon dating based on assumptions?
Radja Callier
# Is radiocarbon dating based on assumptions?

(Asked by: username_0 on 2019-07-13)

<https://benpiper.com/2011/07/the-truth-about-carbon-dating/>

The site above explains that Carbon-14 dating is based on a few assumptions, like to deduce the age of an organism by looking at the amount of Carbon-14 left in it and calculating its age based on the time it should have taken for the missing Carbon-14 to decay. However, these assumptions our wrong because the ratio of Carbon-12 to Carbon-14 in the atmosphere has not remained constant and scientists are not able to know. It also states that other radiometric dating methods have similar problems and that these dating methods should be taken with a grain of salt. Is it true that is all assumption and how can we believe these dates?

**Tags:** radioactivity

> **Comments:**
> **username_1**: Looking at the books, papers published & the training videos on the author's website, it is obvious his "expertise" is in the fields of architecture & information technology (computers), not radiation dating techniques, such as Carbon-14. He is not professionally qualified to give authoritative comments about Carbon-14 or any other form of radiation dating method.  
> **username_2**: All science is based on assumptions the only question is whether those assumptions are well supported. Other radiometric dating methods are already answered in other questions like this please ask it as a separate question if you find them unacceptable. https://earthscience.stackexchange.com/questions/864/how-can-scientists-be-confident-of-isotope-ratios-in-past-eras-and-varied-locati  

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## 2 answers

### Answer by username_2 on 2019-07-13. Score: 8

First modern carbon dating does not assume constant Carbon isotope ratios, in fact it is calibrated against known changes in atmospheric concentration, and has been since the 90's. These [baselines](https://books.google.com/books/about/Radiocarbon_Dating.html?id=SjsSugCVvC0C&source=kp_book_description) were created using annular tree rings which of course reflect the atmospheric carbon when each ring was grown as well as ice core data. This was an issue with the earliest forms of carbon dating (and carbon dating alone) which is why they tended to have huge error bars. Using this as an argument against modern dating is like complaining that automobiles are unsafe because they lack doors or windscreens, it shows the person has not kept up with the development of the technology. Especially considering even the wiki for carbon dating addresses the issue at length, so it is likely willful ignorance.

Second dating method are checked against each other, using things like tree rings, stratigraphy, fission tracks, etc. The are also checked against multiple samples. If multiple samples from multiple dating methods arrive at similar dates that is very good evidence of accuracy.

Other radiometric dating method don't rely on ambient conditions just basic chemistry so this is a non-issue. If you want to know more about them I suggest you ask a separate question or review the several existing answered questions about them.


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### Answer by username_3 on 2023-03-15. Score: 3

It's very important to realize that Carbon-14 dating cannot be used to date anything older than 100,000 years, even with the most advanced technology we have today. The half-life is not long enough for traces (i.e. measurable amounts) to last that long. So it's a misnomer to think that Carbon-14 dating is responsible for dating rocks, fossils, etc. beyond that time frame.

Instead, other radiometric methods like Potassium-Argon dating are used, which have much longer half lives. Even with these methods, however, we must remember the concept that we can't "measure" age. It's not a physical property we can observe like mass or volume. The concept behind these methods is to measure current decay rate, and work back from the present proportion of decay elements to find the assumed starting point. We do have to rely on the assumption that decay rates have been concept, that we can accurately estimate the starting element, and that it's been a closed system for the entire time.

So yes, even the most "conclusive" dating methods rely on assumptions. There's no way around it. There is even good reason to reject these assumptions on occasion. For instance, Mt. Saint Helens gave us rocks with known ages because of observation, which we saw to have much larger proportions of decay elements than we typically assume, leading dating methods to date them at millions of years old when in reality they were less than 50 years old.

> **Comments:**
> **username_4**: Is that last sentence really accurate?  I looked for information about it and found a bunch of stuff about a young earth creationist sending samples from Mt. St. Helens, and eventually a couple of things by actual geologists explaining why the results were wrong - specifically that the lab's equipment was unable to accurately date anything under 2 million years old.  

---

