I really don’t know.
As far as human perception is concerned, nothing can truly be said to be outside of our minds. Talking to you is a good example. As far as my mind is concerned, I believe you exist because I am perceiving you as separate from me, if only through text online. However, cut off my internet access, and you, for all intents and purposes, cease to exist for me. You are no longer within my universe.
If all is Mind, as the Kybalion teaches, then conscious perception is required to experience any thing at all, but that conscious perception is automatically coloured by the lens of beliefs and ideas held within the consciousness doing the perceiving.
So far in my adventures in the occult, I have not experienced anything that couldn’t be explained by the purely psychological model. It accounts a lot for the disparate beliefs that abound with the occult as a whole, and I have found that very little information I have received ever contradicts what I myself believe.
I don’t believe in the nonsense spouted by people like Zecharia Sitchin and his followers about how the Sumerian mythology is actually about extraterrestrials, for example, and so I never receive any information about Nephilim or “reptilians,” or any of that stuff, even if I bother to ask. As they say in religious circles, believing is seeing.
People on this forum claim to be a lot of things, and while that might be their subjective reality, it certainly is not their objective reality. It you performed a DNA test on one of the people claiming to be a demon or a reptilian, for example, I’d wager the result will show nothing but standard human DNA.
We have people coming here all the time, wearing their biases on their sleeve, like the one who asked how they could become a Nephilim or the one who wanted to be a vampire. They already hold this idea in their mind that they can be this mythical being, and so they disregard anything that says otherwise, even to the point of ignoring physical evidence to the contrary.
Just by writing this, I am showing my biases. I do not see the web page cited by the OP as valid. I have a pretty good grasp on scientific basics, and I know a single study means nothing. The power of science lies in the replication of results by others, and until that happens, this idea about the human race being only 6000 years old, is just one among many fringe ideas various people have tried to use science to prove (some formerly fringe ideas have actually been proven; however, most have not).
If I was to ask the demon I am evoking tonight the question about how old humanity is, I’m pretty sure I already know the answer I will receive.