Let’s also use a second method to test the validity of this number.
For the purpose of argument, let’s say that you appear 500,000 years ago. That would mean that, on average, you meet one new person a year.
Sounds very low by our standards, but the vast majority of the meeting will take place during the past 10,000 years, with the rise of agriculture and urbanisation.
So let’s assume that you’re meeting 400,000 of those people during the past 10,000 years. That’s forty people a year.
Very rough estimate: the first human appeared about 5 million years ago. Every year, you meet between 1 and 100 new people. So you would have met between 5 million and 500 million people by now.
Where do you get five million from?
Is that for the Homo genus? Because I don’t think it’s valid for Homo sapiens.
Although I didn’t follow Homo sapiens with my 500,000 year estimate either. That’s much shorter.
Depends what you mean by “human”… I was thinking about the Homo genus.
Why are you being evasive? I just wondered whether you were trying to go by Homo as a whole or H. sapiens specifically, or something in between.
Ah, cool.
Then again, I don’t think even the whole genus is considered to be as much as five million years old.
I’m not sure hominins as a group separate from chimpanzees even existed five million years ago.
Wikipedia suggests that Homo, Austrolopithecus and Paranthropus are all younger than that.
Huh, Wiki offers seven million years as the rough age of hominins. Oh, but that usage (Hominini) contains the chimpanzees.
Imagine being completely immortal (in some fully indestructible sense), but becoming stuck in some remote location, like covered in a rock slide, buried in a collapsed mine/tunnel, trapped in a sunken ship, falling into a deep crevasse, etc. Seems unlikely and perhaps one could avoid most cases by being careful, but on a long enough time scale, eventually winding up in such a situation becomes more likely…
Or, being discovered and somehow exploited by a nefarious government or organization.
Have you seen the film The Man from Earth - Wikipedia ?
Looks like what we want (the “human-branch apes”) is called Hominina or Australopithecina and is reckoned to be around six million years old.
But I’m not sure how that dating was reached, since all the genera inside it (Homo, Australopithecus and Kenyanthropus) are given as much younger, 3–4 mya.
Not clear indeed what should be considered as the first “human”.
Should Australopithecus africanus be considered as human? What about other bipeds like Ardipithecus - Wikipedia ?
My common sense interpretation is that you can’t walk around meeting people in 5,000 BC if you’re a hairy ape man with 50 IQ * who probably can’t even speak.
I’ll give you that you could be a Neanderthal, or a Denisovan, or in any of the Homo species. I’m willing to believe that they could blend in. Even H. erectus, maaaaaaaaaybe. Though that’s probably already pushing it.
(* What is a mentally deficient IQ? I originally had 70 down, but that seemed a bit too realistic. Well, IQ is kinda bullshit anyway.)
Interesting, I thought that I was lowballing the age of H. sapiens at 500,000 years.
Wiki gives only 300,000, and about 400,000 for the Neanderthals.
In early human history, don’t you think you’d be pretty lucky to meet a hundred people in a year?
You’re hunting and gathering. Perhaps the population density is one person per km, or less. How are you going to to be meeting all these people?
What do you mean by “meeting people”? Chimps can’t speak but do have a social life.
So you’re saying we’re basically a chimp, and we stay in the jungle interacting at an animal level with other chimps for five million years?
Doesn’t seem in the spirit of the question.
I don’t know what is the spirit of the question, I can’t read other Homo Sapiens’ minds.
I didn’t expect this question to ignite such fiery debate
It’d be interesting to imagine a genealogy featuring an immortal person.
The same man or woman would appear again and again at the edges of different parts of your family tree, joining into it at different times.
And think how complex it would be to discuss the position of the immortal person to their various lines of descendants.
That also raises the questions if immortal people remain fertile after their 1st century (maybe depends on if they are male or female) and if the immortaility trait would be hereditary.
My answer to @gia’s question would be about 1-3 million.
Like @bugcat, I take homo sapiens to be roughly 500.000 years old, and an early specimen might still pass as a regular person today (although their features would be quite crude with abnormally heavy eyebrows and protruding mouth):
Modern homo sapiens:
During most of the history of homo sapiens, I think people would be living in a small family tribe with maybe 25 people, of which about 1-2 persons per year would be replaced by death and birth of tribe members. Maybe multiply that by 6 if you count infants that die early in their life.
In modern times, people may meet dozens or even hundreds of new people per year, but this hardly matters, because modern times have been around only very briefly on that 500,000 year time scale.
I think even only 200 years ago, most people would live their whole life in a small village where strangers were rare.
Tangential
How many people would you suppose the main characters of X-Men Origins: Wolverine - Wikipedia,
Highlander (film) - Wikipedia,
Keanu Reeves - Wikipedia (since keanu reeves is immortal) have interacted with?
I was thinking how an Eternals character wouldn’t know a spoiler for another character and tbh I was expecting (@yebellz) one of the sciencey mathy computing answers, but I like where this is going. 
