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> Correlation of latitude with skin colour is evidence of causation. Correlation is not causation. I'm sorry but I don't think you have any evidence at all tha

> Correlation of latitude with skin colour is evidence of causation. Correlation is not causation. I'm sorry but I don't think you have any evidence at all that lighter skin was caused by a need for more vitamin D. It's just an educated guess on your part. Lighter skin could have just as easily been an adaptation related to less visibility to predators and prey in snow. Like the article I cited said "researchers are now learning that other factors must have been at play." And with the article that started this thread we now have quite a few studies telling us that vitamin D supplementation doesn't do anything helpful. So why would humans undergo an adaptation that provides no benefit? Perhaps exposure to the sun provides health benefits? Or is it that healthy people get outside more and therefor have higher vitamin D levels? I'm happy saying "I don't know" and asking more questions. I encourage you to do the same instead of claiming causation when all you have is correlation.

0-_-0 6y ago
Correlation is not causation, but you didn't ask for proof, you asked for evidence, and correlation is evidence. For example, do you know whether smoking causes cancer? Because all the evidence we have that it does is based on correlation. Or you're happy saying "I don't know" and asking more questions? How would you show a causal link between vitamin D deficiency causing the evolution of light skin colour without being able to conduct a double blind study? It's fundamentally impossible to prove, all we have is evidence, which is this case is sufficient to say as the first sentence in Wikipedia [1]: "An abundance of clinical and epidemiological evidence supports that light skin pigmentation developed due to the importance of maintaining vitamin D3 production in the skin" [1] https://en.wikipedia.org/wiki/Light_skin#Evolution https://en.wikipedia.org/wiki/Light_skin#Evolution
- tchaffee 6y ago
  > you didn't ask for proof, you asked for evidence I didn't ask for evidence from you. I asked more specifically "Are there any studies giving strong evidence as to the causation for evolving white skin? > do you know whether smoking causes cancer? Because all the evidence we have that it does is based on correlation. That's wrong. We understand why smoking causes cancer. Just for example one of chemicals produced by tobacco smoke is benzoapyrene which is a DNA disruptor, producing mutations that can lead to cancer. [1] > It's fundamentally impossible to prove, all we have is evidence. That's progress. We've gone from "It must be important if it was worth evolving white skin over" to "we can't prove that's why we have white skin". The Wikipedia sentence claims an "abundance" of evidence and then only gives one source, which is behind a paywall. So I'm going to recommend an edit to that article to either give more sources or change the "abundance" claim. Furthermore just a few sentences later it contradicts itself with this: "This accounts for the development of dark skin pigmentation of people living near the equator but does not account for the increasingly lighter-skinned people living outside the tropics." Yet more doubt as to why we have white skin. From your source. Finally, the article that started this discussion provides strong evidence that our need for vitamin D is less important than we previously thought. For sure very low levels of vitamin D are dangerous. But the link between vitamin D and health could be reverse causation: sick people stay inside and therefor have less vitamin D. It could also be that exposure to sun provides something more important to health than vitamin D that we are not aware of yet. So the claim that we evolved white skin just for vitamin D is increasingly on less stable ground. I'll stop here because I'm happy that you've gone from what seemed like a factual claim to you claiming that it's something we cannot prove. Who knows, maybe someone clever can prove it. But it sure does seem like the evidence itself (about both vitamin D and skin color) is fairly rapidly changing. [1] https://www.mskcc.org/news/how-do-cigarettes-cause-cancer https://www.mskcc.org/news/how-do-cigarettes-cause-cancer
  - 0-_-0 6y ago
    > I didn't ask for evidence from you. I asked more specifically "Are there any studies giving strong evidence as to the causation for evolving white skin? Correlation is evidence of causation, and the correlation between skin colour and latitude comes from studies. Therefore I provided that evidence. > We've gone from "It must be important if it was worth evolving white skin over" to "we can't prove that's why we have white skin". We did evolve white skin to produce vitamin D, the evidence is overwhelming. Just like evidence was overwhelming about smoking causing cancer, even before the 2018 article you linked came out. You seem to be misunderstanding the Wikipedia article. It's not contradicting itself. The correct interpretation is that the need for dark skin at the equators doesn't explain white skin nearer the poles, therefore there must be a different reason for it (vitamin D). That article wikipedia links to can be found on SciHub. Overall, your approach reminds me of creationists that claim that evolution is "just a theory" because noone has ever proven it in a lab, and correlation is not causation. And tobacco companies who have denied that smoking causes cancer because correlation does not equal causation.

0-_-0 6y ago

Correlation is not causation, but you didn't ask for proof, you asked for evidence, and correlation is evidence. For example, do you know whether smoking causes cancer? Because all the evidence we have that it does is based on correlation. Or you're happy saying "I don't know" and asking more questions? How would you show a causal link between vitamin D deficiency causing the evolution of light skin colour without being able to conduct a double blind study? It's fundamentally impossible to prove, all we have is evidence, which is this case is sufficient to say as the first sentence in Wikipedia [1]: "An abundance of clinical and epidemiological evidence supports that light skin pigmentation developed due to the importance of maintaining vitamin D3 production in the skin" [1] https://en.wikipedia.org/wiki/Light_skin#Evolution https://en.wikipedia.org/wiki/Light_skin#Evolution

tchaffee 6y ago
> you didn't ask for proof, you asked for evidence I didn't ask for evidence from you. I asked more specifically "Are there any studies giving strong evidence as to the causation for evolving white skin? > do you know whether smoking causes cancer? Because all the evidence we have that it does is based on correlation. That's wrong. We understand why smoking causes cancer. Just for example one of chemicals produced by tobacco smoke is benzoapyrene which is a DNA disruptor, producing mutations that can lead to cancer. [1] > It's fundamentally impossible to prove, all we have is evidence. That's progress. We've gone from "It must be important if it was worth evolving white skin over" to "we can't prove that's why we have white skin". The Wikipedia sentence claims an "abundance" of evidence and then only gives one source, which is behind a paywall. So I'm going to recommend an edit to that article to either give more sources or change the "abundance" claim. Furthermore just a few sentences later it contradicts itself with this: "This accounts for the development of dark skin pigmentation of people living near the equator but does not account for the increasingly lighter-skinned people living outside the tropics." Yet more doubt as to why we have white skin. From your source. Finally, the article that started this discussion provides strong evidence that our need for vitamin D is less important than we previously thought. For sure very low levels of vitamin D are dangerous. But the link between vitamin D and health could be reverse causation: sick people stay inside and therefor have less vitamin D. It could also be that exposure to sun provides something more important to health than vitamin D that we are not aware of yet. So the claim that we evolved white skin just for vitamin D is increasingly on less stable ground. I'll stop here because I'm happy that you've gone from what seemed like a factual claim to you claiming that it's something we cannot prove. Who knows, maybe someone clever can prove it. But it sure does seem like the evidence itself (about both vitamin D and skin color) is fairly rapidly changing. [1] https://www.mskcc.org/news/how-do-cigarettes-cause-cancer https://www.mskcc.org/news/how-do-cigarettes-cause-cancer
- 0-_-0 6y ago
  > I didn't ask for evidence from you. I asked more specifically "Are there any studies giving strong evidence as to the causation for evolving white skin? Correlation is evidence of causation, and the correlation between skin colour and latitude comes from studies. Therefore I provided that evidence. > We've gone from "It must be important if it was worth evolving white skin over" to "we can't prove that's why we have white skin". We did evolve white skin to produce vitamin D, the evidence is overwhelming. Just like evidence was overwhelming about smoking causing cancer, even before the 2018 article you linked came out. You seem to be misunderstanding the Wikipedia article. It's not contradicting itself. The correct interpretation is that the need for dark skin at the equators doesn't explain white skin nearer the poles, therefore there must be a different reason for it (vitamin D). That article wikipedia links to can be found on SciHub. Overall, your approach reminds me of creationists that claim that evolution is "just a theory" because noone has ever proven it in a lab, and correlation is not causation. And tobacco companies who have denied that smoking causes cancer because correlation does not equal causation.