The possibility of an earlier modern human migration out of Africa—at least as far back as 220,000 y

Discussion in 'Biology & Genetics' started by geek, Feb 12, 2019.

  1. geek Registered Member

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  3. ForrestDean Registered Senior Member

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    I would not be surprised at all if there were human civilizations on this planet dating back hundreds of millions of years or more.
     
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  5. James R Just this guy, you know? Staff Member

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    Why wouldn't you be surprised?
     
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  7. ForrestDean Registered Senior Member

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    Because I wouldn't. Not in the least. It's plausible.
     
  8. James R Just this guy, you know? Staff Member

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    Why do you think it's plausible? Plausible based on what?
     
  9. ForrestDean Registered Senior Member

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    Based on the Earth being here for billions of years. Now, I'm starting to get the giggles. I'm curious, is there some reason why you want me to be surprised that there could've been previous civilizations in Earth's history?
     
  10. James R Just this guy, you know? Staff Member

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    Well, I thought that if you were at all aware of the fossil record, for example, then the idea of human beings existing hundreds of millions of years ago should probably strike you as surprising.

    I mean, you are contemplating human beings existing much as they do today, but coexisting with dinosaurs (for example). There's zero evidence of that, and much evidence against it, as far as I'm aware.

    But now you're telling me that you think it might be possible just because the Earth is billions of years old. That's not a very good basis for that particular speculation, if you ask me.

    I'm interested in how people arrive at the views they hold, which is why I asked you.
     
  11. ForrestDean Registered Senior Member

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    Ok.
     
  12. James R Just this guy, you know? Staff Member

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    Maybe I came across as a bit harsh there.

    You know is that the Earth is several billion years old. You're also aware that human beings have been around for at least 2000 years (we're in the year 2019, after all). If the question is "How long have human beings been on Earth?" then, based on that information alone, the reasonable answer is "Some amount of time between several billions years and 2000 years."

    It's also more likely that human beings have been around for only 1 million years rather than for, say, 1 billion years, based on the observation that we're here now and it is apparent that lots of other species have gone extinct.

    So, if this is all you have to go on, it's not unreasonable to say something like "I wouldn't be surprised if human beings were around 200 million years ago". On the other hand, you could equally say that you wouldn't be surprised if it turned out that human beings had only been around for 10,000 years, or 1 million years, or for 3.5 billion years.

    Point is, there's a huge range of possibilities until you gather more information to narrow things down.

    I guess I take my own knowledge for granted, and it's unfair to do that. While I'm no archaeologist, I am aware, for example, of evidence that shows that the dinosaurs largely disappeared when a meteor hit the Earth 65 million years ago, and also of evidence that modern mammals evolved after that extinction event. So, on that basis alone, it is inconceivable to me that human beings could have been around more than 100 million years ago. With a bit more knowledge about the fossil record it becomes surprising to me for anybody to suggest that human beings might have been around any time before about 5 million years ago (being conservative about it). But, like I said, this is based on what I have managed to pick up over the years regarding geological timelines, evolution and the like.

    Everybody has to start somewhere, I guess, and I should not be taking people to task just for not knowing something I know. On the other hand, there are plenty of sources that could be consulted if one really was interested in our best estimate of just how long human beings have existed in more or less our current form, and they aren't very hard to find.
     
  13. RainbowSingularity Valued Senior Member

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    do all civilizations leave fossil remains ?
    what clear indicators do we have as archeological evidence that show the intellectual level of the civilization that it is from ?

    why would such an advanced civilisation that can produce this
    https://en.wikipedia.org/wiki/Antikythera_mechanism

    suddenly disappear and leave no traces ?
     
  14. Michael 345 New year. PRESENT is 69 years old Valued Senior Member

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    Well the fossil record is one thing but you can't beat the documentary Flintstones

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  15. ForrestDean Registered Senior Member

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    Yep, I understand what you're saying. For myself personally, I don't limit my perspectives based on evidence alone. For me, the evidence archaeologists have gathered are nothing more than hints or guidelines or suggestions, and are in no way definitive. One thing I have learned is that we never stop discovering things that disprove or alters our previous theories. The way in which the dinosaurs went extinct is still just a theory. The way in which the dinosaurs looked and behaved is still just a theory. The "Big Bang" is still just a theory. I'm also fairly confident that the quark is not the smallest particle. We will no doubt eventually find something smaller. And then years later something smaller still, and on and on.

    There are way, way too many variables over such an unfathomable period of time to make me say "Wow! I can't believe there were other civilizations on this planet a billion years ago. How is that even possible?" However, I also wouldn't be surprised if humans have been here for only 200,000 years. At the same time, I am just as likely to believe that we came from another star system as much as believing we evolved here on this planet. I don't know where we came from or how long we've been here on THIS planet. But I do know that all the evidence to date isn't enough for me to make a final conclusion. So again, I would in no way be surprised. Curious and interested maybe, but not surprised in the least.
     
  16. James R Just this guy, you know? Staff Member

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    ForrestDean:

    What else do you rely on? Hunches? Guesswork? Gut feeling?

    Archeology is like any other science. Some findings are very well supported by evidence. Some hypotheses are speculative, so that more evidence is needed. To sum up the whole of archaeology by saying all the evidence is "nothing more than hints" suggests to me a somewhat naive impression of what the total weight of evidence in archeology adds up to.

    It's a bit like if you said "The evidence for gravity (things falling downwards) is nothing more than hints or guidelines or suggestions", when there are literally billions of observations of things falling down.

    That is true, but then again it is one thing to adjust a theory on the borderlines of knowledge, but it is quite another to completely overturn a well-established body of knowledge in any scientific field, these days.

    Well, there's a rather suggestive crater in the gulf of Mexico, that dates to just the right time, matching the fossil record, for starters. The extinction itself is not in dispute, again due to the fossil record and to the fact that there aren't any big dinosaurs around today (obviously).

    Also, there aren't that many possible explanations for a mass extinction such as the one that took out the dinosaurs.

    You're right that meteor theory is "just a theory", but it's a rather well supported one, given all the evidence. Put it this way: nobody has come up with an explanation that is more plausible.

    It depends what you're talking about, exactly, and again it's dangerous to make blanket statements.

    Obviously we have a pretty good idea of the musculature and body shapes of many dinosaurs, because that can be deduced from studying their bones. What tends to be more difficult to pin down are features that are more superficial, like an animal's colouring, or whether it had feathers (for example).

    Again, you're right that there is "theory" involved. As in any science, the best theories are based on the accumulation of available evidence.

    Yes. So is the theory of gravity - that things fall down. Both of those theories, as it happens, are very well supported by evidence.

    This brings us back to where we started in this conversation. I feel compelled to ask you the same question as before:

    What makes you "fairly confident" that the quark is not the smallest particle?

    If not evidence, then what? Guesswork? Gut feeling?

    No doubt? Why don't you have any doubt about this?

    Again, you and I differ on this, because I know that the fossil record shows that there was no land-based life on Earth prior to about 430 million years ago. No plants. No insects. No land animals.

    So, if there was a civilisation 1 billion years ago, it must have lived entirely in the ocean. There's zero known evidence of any such civilisation, as far as I'm aware. I would be astonished if some evidence of that were to turn up, literally out of the blue.

    That sounds more reasonable to me, because it's not so obviously in conflict with known facts.

    When you say "we", what do you mean? Life on Earth in general, or human beings specifically? You're not saying that you think that human beings travelled on spaceships to Earth from another star system, are you?

    All the evidence suggests that human beings evolved right here, from earlier forms of life, along with all the other life on this planet.

    There are never really "final conclusions" in science. There are lesser or greater degrees of confidence.
     
  17. ForrestDean Registered Senior Member

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    Hehe, hey look, I get it. Most people don't like entertaining ideas outside their comfort zones. Most people require physical tangible things to validate their existence and reason for being here. People love to hold on to things that keep them safe and give them a sense of security and meaning in this world - A survival instinct I would imagine. It's the reason we have so many religions. For myself, I have no interest in binding and enslaving myself to any beliefs or belief systems, but I am free to believe in any and all things I wish at any time I wish. I could believe in one thing today, and believe in it's complete opposite tomorrow if I choose.

    I have no idea. Again, I don't know where we came from. It's certainly not impossible. It's not like this is the only planet in the Universe with intelligent civilizations living on it.
     
  18. sideshowbob Sorry, wrong number. Valued Senior Member

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    It's true that people are most comfortable within their own knowledge base. The problem arises when people speculate outside their own knowledge base. A biologist and a physicist read the same book about creationism. The biologist says, "The physics sounds good but the biology is nonsense." The physicist says, "The biology sounds good but the physics is nonsense."

    And people with a very small knowledge base like to fool themselves into thinking that other people don't know much either, so they are more prone to empty speculation. I tell them, "You can't think outside the box until you understand the box."
     
  19. ForrestDean Registered Senior Member

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    You see, that’s the thing. I don’t see any of it as nonsense. I also see no problem with speculation. If I am to iliminate speculation outside my own knowledge base is to hinder my own imagination. Also, for me personally there is no box.
     
  20. sideshowbob Sorry, wrong number. Valued Senior Member

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    Yes, that's the problem. You have no base to operate from. You have nothing but speculation. That's no way to learn anything.
     
  21. geek Registered Member

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    How Primitive are our Modern Sciences which we rely on so much... and how hyped they are, Are there really any guide lines to monitor the claims made by modern science, guard our believes, since modern science itself asserts the fact that it does not have a future, ie its future is change!.
     
  22. geek Registered Member

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    So just because Laying eggs leads to traces for now, and mammalic activity dosent leave traces for now, is it taken for granted none of Dinos where mammals..?
     
  23. ForrestDean Registered Senior Member

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    Hehe. Experience is how we learn everything. I don't need physical evidence, information, or documentation to experience. However, I will use whatever physical evidence, information, and documentation are out there that benefits me to my own liking and that has the potential to enhance my experience, but I am in no way bound to it, nor do I restrict myself from using any information regardless of its source. For instance, I could just as easily use information written or spoken from "Lucifer" himself as I could from "God" himself.
     

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