> Honestly, are you really going to be disappointed if, after a few billion years, humanity runs out of gas?

What? Humanity will have entirely disappeared in a million years, and in a billion years we won't even be a distant memory.

Please try to remember that we've only been a distinct species for 200,000 years, and in another 200,000 years, chances are we will have been replaced by something different. In a million years, five times as long, we will not exist in any form whatsoever. In a billion years, five thousand times as long, creatures who have forgotten about us will themselves be forgotten.

It is the height of absurdity to think that a lowly species like us will exist in any form at all even a million years hence. Both us, and all our stellar achievements (like Country & Western music and the Pet Rock), will have completely disappeared.

> Humanity will have entirely disappeared in a million years

Even if you mean that in the narrow sense of H. sapiens, rather than humans as genus Homo, that would make H. sapiens a shorter-lived species that H. erectus. If there's a reason to believe that, you haven't provided it.

> Please try to remember that we've only been a distinct species for 200,000 years

Or 500,000, depending on which view of the relevant taxonomy you take...

> and in another 200,000 years, chances are we will have been replaced by something different.

There is no factual basis for this claim; particularly, even if we except your POV on how long we have been around so far as a species, it does not follow that the same amount of time in the future would see us replaced.

> In a million years, five times as long, we will not exist in any form whatsoever.

Again, you provide no reason to believe this. H. erectus was around for 1.75 million years. If H. sapiens only lasts as long as H. erectus did, our species would be around -- starting from your 200kYa start date for H. sapiens, another 1.5+ million years. And humans, genus Homo, have been around for over 2.5 million years.

> It is the height of absurdity to think that a lowly species like us will exist in any form at all even a million years hence.

It really is not. We may be lowly, but a species lasting a mere 1.2-1.5 million years (what H. sapiens would have to last in total to be around a million years hence) is not uncommon at all. Many hominid species have, why wouldn't H. sapiens?

> What? There is no "factual basis" for my saying "chances are"?

Correct. Exactly.

> I didn't make a statement about fact, I made a statement about probability

Claims about probability still require factual support (and, in fact, are still fact claims -- that, given given particular prior conditions, there exists an X% probability of a particular subsequent event is a fact claim, even if it is a different fact claim than the claim that the subsequent event is certain.)

> the point I successfully made was that five billion years from now, there will be no sign of us to fret over the earth's being absorbed by the red giant star our sun will have become.

There may be a reasonable basis for that conclusion, but if there is, you haven't presented it, so it would be inaccurate to claim that you have successfully made that point, even if it is a point that could have been succesfully made.

>> What? There is no "factual basis" for my saying "chances are"?

> Correct. Exactly.

Honest to God. A statement of probability is not a fact, it is an estimate. You aren't even familiar with the terminology.

> Claims about probability still require factual support ...

False -- they require evidentiary support. A probability estimate requires a basis for making the estimate, which I provided. If you had any understanding of either science or statistics, you would be familiar with what I'm talking about.

Here's the evidence:

1. There are no species that were present on Earth a billion years ago that are still present in the same form, i.e. able to interbreed with their forebears.

2. There are few species that meet the above requirements from 100 million years ago.

3. There are a handful of species that meet the above requirements from 10 million years ago.

4. Modern humans have existed only for 200,000 years.

5. Using the simplest statistical methods, accessible to an average college student, we can write a distribution that takes into account the fact that modern humans didn't exist 200,000 years ago and extrapolate into the future, showing that our likelihood for existing as the same species we are now, 200,000 years in the future, is very small. This is a statement about probability and likelihood, areas with which you are clearly unfamiliar.

6. On the above basis, the probability that modern humans will exist as the same species a billion years from now is zero.

7. On that basis, the probability that modern humans will witness the sun enveloping the earth five billion years from now is also zero.

If you can't understand the above argument, by all means keep your ignorance to yourself.

> There may be a reasonable basis for that conclusion, but if there is, you haven't presented it, so it would be inaccurate to claim that you have successfully made that point, even if it is a point that could have been succesfully made.

Look -- go back to the philosophy department, where contentless arguments like yours, arguments indistinguishable from two children negating each other, are welcome.

In your fantasy, modern humans, which didn't exist 200,000 years ago, have some chance to be present to worry about the sun absorbing the earth five billion years from now. And you think my probabilistic estimates are doubtful. The burden of evidence is yours, not mine.

EDIT: Yes, people, don't bother to read the argument, the evidence, just click the downvote button. Live up to my expectations.

> There are no species that were present on Earth a billion years ago that are still present in the same form, i.e. able to interbreed with their forebears.

That's not really a useful basis for conclusions about the outer limits for either species in general or any particular species, as sexual reproduction itself may only be around 1 billion years old (from what I can tell, that's the age of the oldest fossil evidence), but, in any case, the oldest animal species seems to be around a 445 million years old, which is a sizable fraction of the time that multicellular life has existed on earth.

> Using the simplest statistical methods, accessible to an average college student, we can write a distribution that takes into account the fact that modern humans didn't exist 200,000 years ago and extrapolate into the future, showing that our likelihood for existing as the same species we are now, 200,000 years in the future, is very small.

No, you can't, because none of the facts that you cite would support any calculation that would lead to that conclusion. If you assume that species total lifespans are randomly distributed (a dubious assumption), and you make the further assumptions that the lifespans evident from the fossil record accurately represent the full lifespans of species (also dubious), you could calculate a distribution function for the actuarial expected future lifespan of a species given how long it has existed previously. But even if the necessary assumptions weren't problematic, none of the premises you cite (alone or together) would support the conclusion that "modern humans", being around 200,000 (even assuming that "modern humans" are even a species and not just a subgroup within a species, which is an actively disputed point) would, as a species, only be around another 200,000 years.

> On the above basis, the probability that modern humans will exist as the same species a billion years from now is zero.

This further conclusion -- and the following one -- fails to be supported because it rests on the prior failed conclusions.

> If you can't understand the above argument

I understand it -- its a stream of statements that you assert follow from each other that don't.

> In your fantasy, modern humans, which didn't exist 200,000 years ago, have some chance to be present to worry about the sun absorbing the earth five billion years from now.

No, I haven't made any positive claim about the likelihood of that happening. You've made a claim about it, but its a claim that rests on dubious stated premises, and, on top of that, doesn't even follow from those premises.

>> There are no species that were present on Earth a billion years ago that are still present in the same form, i.e. able to interbreed with their forebears.

> That's not really a useful basis for conclusions about the outer limits for either species in general or any particular species, as sexual reproduction itself may only be around 1 billion years old (from what I can tell, that's the age of the oldest fossil evidence), but, in any case, the oldest animal species seems to be around a 445 million years old, which is a sizable fraction of the time that multicellular life has existed on earth.

First, you have simply confirmed what I said above, while simultaneously attempting to deny its evidentiary basis.

Second, let me explain something to you, something you very clearly do not understand. You are trolling. You have nothing constructive to offer this discussion, you offer no evidence or productive arguments of your own, and you are constantly restating the terms of the argument to suit yourself. If I offer a guess about the future based on statistical probability, you reinterpret that clearly stated guess as a statement of fact about the future, and call it false. But in point of fact, probabilistic guesses about the future are neither true nor false.

You have yet to argue against what I have actually said -- instead you argue against a series of straw men of your own fabrication.

Stop trolling -- it's not constructive, it's a waste of time, and it makes you look inexperienced and narcissistic.

I don't find lutusp's points to be all that unreasonable. While you passionately assert that they're false or poorly reasoned, I really haven't been able to figure out from your post what you think the exact problem is.

If there's not a single species present today which was also present 1B years ago, it does not seem unreasonable to me to suppose that humans will not be around in five times that timespan in the future. If anything, this should be the default supposition, and it is any claim to the contrary -- that we will be around in 5B years, in a form we could mate with -- which needs extra support.