Basis of science's belief that extraterrestrial life is likely?

Given Blake’s views, isn’t this kind of like asking him to bet on the probability that the sentence I’m thinking of in my head is false?

He has no basis for making a bet.

Given that one of the terms in the Drake Equation

From wikipedia:

Since one of the terms in the equation is “fℓ = the fraction of the above that actually go on to develop life at some point”, I don’t see how you can use the Drake equation to say how likely it is that a planet capable of supporting life will go on to develop life at some point. It is an unknown value, and we can plug in whatever number seems good to us. It could be .97, or 0.00000000000001.

The Drake equation is just a way of trying to make explicit our assumptions about how likely we are to find extraterrestrial life. But we can only guess at most of those terms. We know pretty well how many stars there are in the galaxy, and in the last decade we’ve determined that planets are pretty common, and we’ve found a couple of bodies that are at the right distance from their star that liquid water might exist. But even if liquid water might exist at that distance, it doesn’t prove it does exist–the Earth and the Moon are at the same average distance from the Sun, and yet the Moon isn’t covered with liquid water.

And so all the Drake Equation does is give us more things to disagree about. But at least we’d be disagreeing on a higher level.

I’m just going to throw in a quick plug for “At Home in the Universe” by Stuart Kauffman. It’s a decade or two old now, but he argues convincingly for the idea that the emergence of life, rather than being vanishingly unlikely, could actually be all but inevitable given a system of sufficient chemical complexity. He backs this up with computer simulations.

Light is light, heat is heat, water is water, chemical stability is chemical stability, and energy flow in an open system is energy flow in an open system.

There’s no orgone field or or any particular specialness about earth’s placement in the universe that anyone can point to and say “This is why we won the lottery of abiogenesis”
There’s not even proof that abiogenesis ever occurred on earth.

If folks want to claim that there’s something special, or unique, about earth’s place in the universe, they ought to make an effort to point out something that can be verified as a special uniqueness.

Otherwise, Occam tells us we’re just another gas covered rock in space.

Do we? If so then why are there so many papers in premier journals that posit an extraterrestrial origin of life? There are serious journal articles that posit that the first amino acids and even proteins originated in interstellar gas clouds.

Could you tell me what you believe these approximate conditions for the origin of life are, and how you ascertained them.

Do we? For example if life really does require an anomalously large, Earth type moon to exist *before *it gets seeded from a nebula, just as two possible factors, then what are the odds of that happening? It requires a large planetoid in an irregular orbit striking at precisely the right speed and angle to knock off a large chunk of the planet and have it go into orbit. After this has happened and the planet cools, it then needs needs to pass through a seeding nebula. How we know that there are billions of planets with such moons that subsequently passed though a seeding nebula for billions of years?

But this is a total non sequitur. If only one planet in 10^9999 ^999 ever has the right conditions for life, then how can you possibly conclude that there are huge number of chances. At that probability the chances are so close to zero as makes no difference.

As Dio is fond of saying, if it requires faith then it isn’t science.

No, nobody has told me how they calculated the probability of life arising on Earth.

If I am mistaken then please quote where somebody explains how they arrived at the figure they used.

Actually, based on experimentation and theory into the conditions and possible methods that caused life to originate it seems ridiculously optimistic.

And this is the problem with argument through assertion. I can assert the exact opposite…

Which experiments lead to that conclusion? What conditions?

Scientists have no idea and can have what the probability is. Zero degrees of freedom, remember The low numbers must be as acceptable to scientists as any higher. If it’s not then they aren’t doing science.

What does the action of an intelligence have to do with anything? Humans are also creating race cars. Does that mean that the odds of a race car spontaneously generating are high?

I honestly can’t see what relevance this statement has to the discussion.

And? I honestly don;t know what point you are trying to make here. What precisely is the relevance of single samples of bones to the discussion.

So it’s being tested. So far the tests have all totally failed to find any life elsewhere, right?

So how does this invalidate a position that life never arose elsewhere?

You did make a declaration though. I;m happy enough now that you have retracted it.

Meanwhile many others think that it is exceedingly unlikely. The pertinent point being that there is exactly the same evidence either way.

Why does it seem more reasonable? All you do is keep repeating the same assertion in different forms, without ever saying why you believe that the odds of life originating on Earth was greater than the total number of subatomic particles in the universe.

What exactly is it that “we” know that gives you reason to believe this?

Nobody is arguing that some theory may be testable. The argument is whether the basis is logical. So far, on those grounds, it has failed. All the testing supports the notion that there is no life outside Earth, correct? So any contention to the contrary has to rely on the logical underpinnings of the theory, correct?

One implicit assumption of modern science is the “averageness” of our position in the universe. This assumption is built in because the human tendancy is to assume we’re special, and that the universe (literally) revolves around us.
Assuming we’re “nothing special” has served science much better.

(I’d include a cite but I can’t remember the formal name for this principle).

Of course, to the OP, it’s that unfortunate word “belief” again. I don’t think scientists believe that there is life out there to the extent that if the data showed a sterile universe (bar us) they would refuse to accept it.
It’s not a religion. It’s more that the starting point is to assume the Earth is not exceptional.

Just an aside: it never ceases to amaze me how the religious will insist that it’s impossible for life to have arisen by any means that doesn’t include an intelligent creator.

Impossible??? IMPOSSIBLE??? How does ANYONE who believes in an all-powerful creator that just “is” have the TEMERITY to use the word “impossible” about anything at all, much less the origin of life?? AND expect to be taken seriously???

REALLY? <—Seth and Amy

Back to the lottery idea.

I guess the reason I don’t like the analogy is that we know that the odds of winning the lottery are small, so we know that the population of lottery winners is biased.

However, we don’t know the value of the likelihood of life arising. If the probability is large, then our sample size of 1 isn’t biased. If the probability is small then we know our sample is biased. But we don’t know.

However, I think a better analogy is to dice rolling. Let’s say Bob goes to a casino and plays a dice rolling game. We don’t know how the game works, but we know that Bob played for only a million years, and won the game. Given that he won the game in that time period, what can we say about the probability of winning? That is, if he got to roll the dice a million times a year, and did it over a million years, and won, we could use Bayesian probability to work out an idea of how hard the game was likely to be. I’m not sure exactly how to do this, because Bayesian reasoning makes my head hurt.

Actually, it’s a mathematical certainty that the conditions will be met billions of times. They’ll just etnd to be spread very far apart.

There’s nothing scientific about it.

They don’t assume it, but they know this combination works, so they’re being conservative by only considering what they already know can happen.


I suggest that the first step would be to reconstruct the list of criteria; then apply those criteria to our own galaxy.

Seems to me the odds of finding another planet that met the criteria would be negligible.

You’re going to have to produce some numbers before this claim has any credibility.

Note by the way that the above comment is coming from someone sympathetic to your position.

You made a statement of fact in GQ. I called you on it, and you then admitted that you had no basis whatsoever for the claim.

That is not nitpicking. That is the whole reason we are here. This forum is for factual answers. As it transpires your statement wasn’t fact, though you presented it as one.

So you have gone from total disagreement with me, to utter and total wholehearted agreement?

Good. We both agree.

Not bet.

There is going to be a cockfight in a tin shed in downtown Hanoi tonight. Two birds are fighting, we’ll call them A and B. Which rooster are you going to bet on would you bet on if you were a betting man?

Your question is literally that ridiculous. You have no information whatsoever upon which to place your bet. Why on Earth would you make the bet in the first place? And if you did place the bet, why would you believe that either choice was better?

Really, you have just admitted that we do not know whether life is ubiquitous or unique. Your own words: “there is no way to say and we can only guess.” Yet for some reason you are prepared to take bets that it is ubiquitous.

I’ll offer you the same conditions on my bet. I mean it, really. We’ll see whether you really believe what you are saying or whether you know this is nonsense. Here are the conditions.

We’ll have a doper select a random date, another select a random city and two more select random numbers. Then we’ll put them together. The result is the date, gym, boxer and match number you are betting on.

You will have to put all your money and worldly possession up on a single bet on that boxer, you get to choose whether to bet on a win or a loss. If you lose I get it all. If you win I’ll double it.

Of course you have to make your decision to gamble before the numbers are selected so that, as you yourself said, “there is no way to say and you can only guess” which way to bet.

So which way do you want to bet? Will your boxer win or lose.

Your bet is at least as ridiculous as this. You admit yourself that “there is no way to say and we can only guess” what the result is.

The same right back at you.

There are 500 billion stars in our galaxy. If the proper planetary conditions occur on one in a billion stars then it would happen 500 times in our galaxy, and there are hundreds of billions of other galaxies.

Seems like Dio disagrees with you. :smiley:

Since he is refusing to even address our criticisms, it seems that he has realised how silly what he said was. It would be nice if he would admit it though.

That is the whole point of the analogy. It illustrates that using self selected winners will result in an unreliable probability where the odds of winning are small.

Now assume that the odds of life originating on any planet are small. What does the selection of our planet due to our living here do to our ability to predict the odds of life arising? Do you agree that if the odds were small we could not get an accurate probability? That any probabilities we calculate will be grossly overblown if the odds are low?

If so then the analogy is perfect.

There isn’t any point to arguing with creationists.

For your argument to have creditability, you need to tell us what the probability of life arising on an earthlike planet is, and how you arrived at that probability.

And if the proper planetary conditions occur on one in a 10^87 stars? Then of course it’s a near certainty that life doesn’t exist anywhere else.

The point **Dio **refuses to admit is that my figure is precisely as plausible as his. We both have exactly the same amount of evidence and logic for each of our figures.

I have asked **Dio **multiple times in this thread to show us how he obtained his figure, but he just handwaves to the Wikipedia article Drake Equation", even though the article itself notes that the equation can produce any answer at all with exactly the same validity.