Interstellar travel?

[Lexicus]

Your sample size is one. You don't get to make a statistical analysis about diamonds out of one diamond and a bunch of rocks.

Well, if you want to look at the statistical characteristics of diamonds, sure, but not if you want to look at how likely it is for other kinds of rocks to turn into diamonds, or something similar.

It's certainly hard to believe, giving that octopi have the same protein structure and amino-acid coding sequence as all the other Earth inhabitants.
We must have common ancestors with them.

Given the number of instances of convergent evolution we already know of in Earth history, this isn't quite as airtight an objection as you might think.

 

[Timsup2nothin]

There is definitely other life out there. Anyone willing to take a $100 bet with me feel free to send me a private message, but just be aware that it will never be possible to prove that you won the bet.

If you can't prove it, how does you being willing to bet on it make it "definite"?

 

[Timsup2nothin]

Well, if you want to look at the statistical characteristics of diamonds, sure, but not if you want to look at how likely it is for one kind of rock to turn into a diamond, or something similar.

If we're looking at the statistical characteristics of life, we have one sample. If we are looking at intelligent life as a characteristic of planets, again we have one sample even though we have a bunch of planets.

 

[El_Machinae]

Statistically speaking it's unlikely for something to happen only once in such a vast universe. You can say that without putting exact numbers on the probabilities.

You don't need to put exact numbers on it, since you have phrased it in a binary setting. You said it is more likely that there is other life than not. Manfred isn't saying that he disagrees with your calculation, and he has a different number. He's saying that no calculation is valid.

 

[red_elk]

Apparently a lot of our (human) DNA made it into our cells via viruses and not from any sort of human ancestor.

I'm not talking about genes, rather about the coding structure itself - AGCT nitrogenous bases, coding sequences for aminoacids, etc. All life on Earth seem to share these principles.

Mind you it does seem unlikely to me that life that arose independently elsewhere would contain something that's compatible with our DNA

Yes, that's my point entirely.

Given the number of instances of convergent evolution we already know of in Earth history, this isn't quite as airtight an objection as you might think.

We haven't seen any instance of evolution which changed the DNA coding rules. Besides that, I very much doubt octopus is a good example of convergent evolution.

 

[Timsup2nothin]

You don't need to put exact numbers on it, since you have phrased it in a binary setting. You said it is more likely that there is other life than not. Manfred isn't saying that he disagrees with your calculation, and he has a different number. He's saying that no calculation is valid.

Actually he said there definitely is, as proven by the fact that he is willing to bet on it. I could provide the quote, but it's such a near past event in this very thread that it seems like I shouldn't have to.

 

[El_Machinae]

Debates on extraterrestrials aside, I think that humanity's future should include us being interstellar. After that, it's a question of how good our existence is in that stage. There's a feedback obviously, we should only become Interstellar if we think there is a good enough chance that it will be a good life out there. If you are indifferent to humanity's extinction then any suggestion that we become interstellar will not resonate

 

[Lexicus]

If we are looking at intelligent life as a characteristic of planets, again we have one sample even though we have a bunch of planets.

Maybe I don't understand what you mean by "looking at life as a characteristic of planets," but again it just seems obvious to me that if the question we're answering is how often life occurs then our sample is all the planets, or perhaps all the rocky planets, not just the ones with life on them.
Part of the problem here is that we don't really know what we're looking for. We don't know whether life on another planet might be totally different from life on Earth, or whether the same basic chemistry is going on in all life everywhere. In that sense we don't even really know how to define "life."

We haven't seen any instance of evolution which changed the DNA coding rules. Besides that, I very much doubt octopus is a good example of convergent evolution.

That is true. But as I implied upthread I find it very unlikely that current DNA-based life assembled itself directly from nonliving matter.

You don't need to put exact numbers on it, since you have phrased it in a binary setting. You said it is more likely that there is other life than not. Manfred isn't saying that he disagrees with your calculation, and he has a different number. He's saying that no calculation is valid.

I agree with your analysis of the situation, but there are plenty of positions in between "exact numbers" and "no calculation is valid." There are principles like the mediocrity principle that we can use to say that some unknown probability (the probability that there are many planets like Earth) is definitely larger than some other unknown probability (that the Earth is unique). And this is actually not incompatible with the case that the ultimate truth is that the Earth is unique!

 

[Timsup2nothin]

Maybe I don't understand what you mean by "looking at life as a characteristic of planets," but again it just seems obvious to me that if the question we're answering is how often life occurs then our sample is all the planets, or perhaps all the rocky planets, not just the ones with life on them.
Part of the problem here is that we don't really know what we're looking for. We don't know whether life on another planet might be totally different from life on Earth, or whether the same basic chemistry is going on in all life everywhere. In that sense we don't even really know how to define "life."

Let's say we have a sample of twelve similar planets, one with this life, however we have defined it. We have a data point there that suggests odds of this "life" might be about one in twelve. Of course, one in six is possible, and we've had a bit of "bad luck" in our sampling. Even one in two is possible, though that would require more "bad luck." But the other end is still totally open, because our sample size for "has the characteristic" is one. The real odds could just as easily be one in a hundred, or one in a million, or one in a billion, and our current sample cannot distinguish between those...or distinguish whether or not this "life" business is actually a unique characteristic that we just stumbled upon because we happen to be it.

 

[red_elk]

That is true. But as I implied upthread I find it very unlikely that current DNA-based life assembled itself directly from nonliving matter.

You think it evolved from something more primitive, that there were non-DNA (or non-RNA) based lifeforms, which are now extinct?

 

[Silurian]

Hunter gatherers dont need wheels, they kill something too large to move they chop it up and walk it away. Rollers are sturdier than wheels and axles/hubs/spokes are tougher to produce and even then they couldn't support enough weight.

google the Baalbek monolith... the only way to move something that big was with rollers. We dont even have modern machinery that can move that monstrosity.

You are using the wrong equipment there. For moving ultraheavy loads there are self-propelled modular transporters (SPMT) that can carry almost any weight. Even whole ships of 10000 or 20000 tons.

I have only worked on one job where we used SPMT.
I have been on a number of jobs where we have had cranes large enough to lift the Baalbek monolith onto a group pf SPMT.
Example from US off youtube, not one of my jobs in UK.

 

[Lexicus]

But the other end is still totally open, because our sample size for "has the characteristic" is one.

Well, I was never disagreeing with that.

 

[Timsup2nothin]

Well, I was never disagreeing with that.

I know. We agreed a couple pages back. That's why I wondered why you asked, but that isn't a reason to not answer.

 

[Akka]

It's not a gotcha play on words. The issue is that uniqueness does exist, and until you have a second example you can't prove that it doesn't apply...or even justify assuming that it doesn't apply.

It's philosophically true, but completely beside the point of the thread.
We aren't debating that there is another Earth elsewhere, we're pointing there is another planet with life (actually, tons of them) out there. That's the same distinction as between saying "there is only on Warpus in the universe" and "there is only one human in the universe".

I think this statement is wrong, but we* went over this ad nauseam in another thread so I wasn't wanting to get into it again here.

*not necessarily me and you, but me and other people. I don't remember who.

Well, you think wrong
There is tons of things we don't know about life, but it's still made out of rather mundane elements that just require a set of factors which are barely on the "uncommon" side.
So unless we discover an especially incredibly rare and restrictive requirement, it's a given there is a big bunch of planets hosting life in our very galaxy, and probably hordes of planets with the potential.
And that's just with the version of life we know of, so not counting the potential different way life can emerge.

 

[Timsup2nothin]

It's philosophically true, but completely beside the point of the thread.
We aren't debating that there is another Earth elsewhere, we're pointing there is another planet with life (actually, tons of them) out there. That's the same distinction as between saying "there is only on Warpus in the universe" and "there is only one human in the universe".

How are you proving that the characteristic "with life" is a common characteristic like "human-ness" rather than a unique characteristic like "warpus-ness." We can assume that with seven billion people there must be one, or maybe a bunch, that are 'just like Warpus,' but until you find a second one you can't be sure that Warpus isn't unique. Or we can say "well, all we are really interested in is his human-ness, not his Warpus-ness, and that is already proven to be not unique," but this "with life" business has yet to be already proven as not unique so his human-ness doesn't really apply as a representative example.

 

[warpus]

You don't need to put exact numbers on it, since you have phrased it in a binary setting. You said it is more likely that there is other life than not. Manfred isn't saying that he disagrees with your calculation, and he has a different number. He's saying that no calculation is valid.

Yep, I am saying that chances are P(1) is not more likely than P(2) + P(3) + P(4) + P(5) + P(6) ... + P(578156) + ...

It could be, but chances are it isn't. I'm not sure what you mean by binary in this context.

The opposite assertion is that P(1) is more likely than all the other probabilities added together, which is possible but far less likely, as it relies on P(1) being much higher than the other probabilities

 

[El_Machinae]

He's not making the opposite assertion. I don't know how to explain. There's not enough information to make either assertion, he's saying.

 

[warpus]

He's not making the opposite assertion. I don't know how to explain. There's not enough information to make either assertion, he's saying.

There isn't enough information to say what the situation is for sure. There isn't enough information to say what the probabilities of events are either. But there is enough information to talk about probabilities of those probabilities, if you are modelling the next "a really really really big number" number of throws

If you have a die in your hand and you have only thrown it once.. and you have no idea how many sides there are on the die.. but you know what number came up when you threw it. you are still able to say things about certain statistical properties of the situation

It's a stupid thing to argue about, really. But I think it's interesting?

Either way we're all going to die once the aliens come so it doesn't really matter

 

[El_Machinae]

Y'all are going to die. Like I said, I plan on being interstellar by the year 3100 CE

 

[Timsup2nothin]

Yep, I am saying that chances are P(1) is not more likely than P(2) + P(3) + P(4) + P(5) + P(6) ... + P(578156) + ...

It could be, but chances are it isn't. I'm not sure what you mean by binary in this context.

The opposite assertion is that P(1) is more likely than all the other probabilities added together, which is possible but far less likely, as it relies on P(1) being much higher than the other probabilities

The binary is that a thing can be either unique, or not unique. If the thing is unique, then all you have with your chain is a sum of zeros. With zero evidence regarding the question of uniqueness you are assuming that "not unique" is inherently more probable than "unique."