I gues sI should probably leave this, but…
A better analogy would be: You will be meeting a trillion-billion different species. There is a non-zero probability that any one of them will have wings.
Technically you are correct. There is no way of knowing whether you will meet a winged species but the odds that you will are looking a lot better, whatever the base probability.
Oh FFS, read the post you quoted.
A scientific basis. Not a scientific theory. A scientific basis.
If you really don’t understand thee difference between those two concepts I will explain it.
WTF?
That is such a blatant strawman that it’s laughable. Nobody could possibly derive such a position from my posts here. At least, not in honesty and good faith. :dubious:
I already answered this clearly and explicitly for you.
If you didn’t understand it then tell me so and I will cheerfully post the relevant quote, so that everybody can see that you are unable to follow the argument.
If you did understand it then this is a deliberate strawman and everyone can see that you are not posting in good faith.
So which is it to be?
Once again, I addressed this explicitly and clearly for you in a previous post.
Once again, if you didn’t understand it then tell me so and I will cheerfully post the relevant quote, so that everybody can see that you are unable to follow the argument.
If you did understand it then this is a deliberate strawman and everyone can see that you are not posting in good faith.
So which is it to be?
Well, yes. It is a blatant and specifically disavowed a strawman. Those tend to be nonsensical. That is why you constructed it after all.
No, but that’s because wings seem to be incompatible with several different and common body types here on earth, and intelligence seems to require some minimum brain size that may almost exclude flight as a possibility on many possible worlds.
On the other hand, I’d guess that any intelligent alien we might encounter - assuming they come to us - are technologically very capable tool-makers and would therefore have some appendages/organs (or technology that supersedes them) that can be used in the same way we use our hands and eyes (with eyes being almost a given, considering the many times they independently evolved on earth).
Blake you are asking for a level of confirmation that is impossible to ascertain with current technology. You are correct technically that the odds are unknowable, but because we have a complete inability to gather further data at the moment it simply makes more sense to go with the positive rather then the negative. We know that life doesn’t necessarily require certain conditions previously thought crucial, (sunlight for example eg: chemosynthetic life) and it exists in areas we previously thought completely inhospitable.
Our sample size of one is contaminated but we we literally have no other choices but to bet of the likelihood of life arising. We do that based on any number of measurable criteria such as the the number of known stars with earthlike planets, and judge that against the huge numbers of galaxies etc. I get that you can argue it the other way, but it is really more of semantic, rather than a literal argument. Just because you don’t know everything about a process doesn’t mean that you can’t make a meaningful estimate based upon what you do. By your logic if we invented stardrive tech tomorrow and started gallavanting around to other worlds we would have to re assess our definition of life each time we found something. “Well we have life on three planets, but that’s no reason to assume it happened anywhere else!”
If you want hard numbers then you win. They aren’t in yet. There. Feel better? Now your completely irrelevant nitpick is conceded. Logic and time has shown us that if something can happen once, then as the odds grow it will happen again, usually with more frequency. This happens far more than the random event that is unable to be duplicated.
I specified “tomorrow” so as to exclude any other factors. Why do you think that it would give us any basis for calculations?
I’m not going to stretch the analogy. I believe you understand my point.
But just in case you really don’t, let me try again: I would like you to tell me the likelihood the fist aliens we meet will have scales.
It doesn’t.
Because it would. 
I’m not sure what you are asking here, the answer seems too obvious. You can obtain a meaningful probability from more than one degree of freedom. The result may not be rigorous, it may not have a very high confidence value, but it will be meaningful.
IOW, I think it will give us a basis for probabilty calculations because 3, 000 years of mathematics and 300 years of statistical research tells us that it will.
The OP formerly said:
Wrong. That is faulty logic and you know it.
“I bought one lottery ticket and won a million, so it must be pretty likely that every lottery ticket wins a million” is analogous to “Life arose on one planet, so every planet must have life on it.”
Some more accurate analogies would be:
“I bought one lottery ticker and won a million, so someone else must have won a million dollars by buying a lottery ticket as well.”
“Life arose on my planet, so life must have arisen on another planet as well.”
Tell me, has there only been ONE lottery winner ever? If the number of lottery winners in the world is greater than one, and less than the total number of lotto tickets sold, you need to reevaluate your position.
How about this, dumb it down for me.
Do you believe it is possible to gather enough scientific evidence to estimate the likelihood of extraterrestrial life, without having any direct evidence of life on other planets?
Dunno. If I had to guess, somewhere between 0.5 and 0.001. Certainly not vanishingly small.
Well, I agree with that, but it doesn’t follow from your previous reasoning at all. If I am to accept your OP, chances of life originating could still be 1/10^87 and we’d have no more reason to assume that it isn’t with two planets instead of one.
I’m not asking for any level of confirmation at all, whatsoever. All I am asking for is that those who claim to have calculated the probabilities show us how they made those calculations.
No it doesn’t.
I addressed this above, several times.
Yes we do. Why can’t we refuse to bet at all? Why is that not another choice?
This seems like a blatant false dilemma.
No, it isn’t semantic, it’s literal.
Exactly, and while we don’t know everything about the reasons why life can’t arise elsewhere, what we do know is that there is no evidence that it did.
Ooop, sorry, were you trying to support the opposite position with that argument?
How did you conclude that from my logic?
So in thread about the *scientific *basis for extraterrestrial life, you feel that pointing to a total absence of hard numbers is a nitpick? :dubious:
Really? As the odds grow the event becomes more likely to happen again? What does it mean to say of an event that the odds are growing? It surely doesn’t mean that the probability of it happening is increasing? Because, if that is what it means, then you have just informed us of the startling fact that, as the odds of an event increase, that event will happen, on average, with more frequency.
While this is certainly true, it is banal and circular and I can’t really see any relevance to the discussion at hand. The whole issue is what the odds are and whether they might increase. Saying that if they do increase then the event becomes more likely hardly seems to add anything.
Really?
So for every random, quantum level fluctuation that can never be duplicated, there are more than one events that will happen multiple times?
For every French revolution there are multiple wars that are exact duplicates of each other?
For every animal born with a unique genotype there is more than one identical twin?
For every snowflake with a unique microscopic and isotopic structure there are more than than one that are identical?
Can we have a reference for this claim? Because on the face of it, it seems absurd. I can think of virtually no events that are even fractionally as complex as life that have ever been duplicated, or even close to duplicated. Yet according to you this is the exception in this universe.
If this question was meant exclusively for Blake, I apologize in advance for my interference. Without direct evidence, you could argue that the answer needs to be a “no” but, imo, this is true only in such a narrow sense, that I consider the point of view not useful any longer.
I think, we can start to talk about likelihood when we are able to answer two questions:
I realize that the conditions we hypothetically find, are not necessarily the only ones to establish life, but it would give us an idea of the lowest threshold.
Sigh.
No, that isn’t what I said.
No, that isn’t my argument.
No, that isn’t the issue that I was addressing.
No, your analogy isn’t in any way valid or even relevant
No, the fact that life arose on one planet has no relevance at all to this discussion.
I’ll simplify.
Someone said that because life arose fast on Earth, it must arise everywhere.
I said that, due to the anthropic principle, life must arise *fast *on any planet with intelligent life. As such looking at the *speed *at which life must have arisen on our planet is invalid as a tool for calculating the probability of life arising on a random planet. Since all planets with intelligent life must also evolve life rapidly, the *speed *at which life arose here can tell us nothing about the probability of it arising on a random planet.
This is perfectly analogous to calculating the speed with which a person will purchase a winning lottery ticket. A lottery win must arise *fast * for any lottery winner, otherwise they would die before they won. As such looking at the *speed *at which a win occurs for a lottery winner is invalid as a tool for calculating the probability of a random player winning the lottery. Since all players who have purchased winning tickets must also purchase a winning ticket rapidly, the *speed *at which a winning ticket was purchased by a winner can tell us nothing about the probability of purchasing a winning ticket at random.
In contrast your analogies don’t even address the issue of the speed at which life arose, so I can’t even see how they are relevant to the issue. I think you have gotten the bull by the tits and totally misunderstood our discussion. You seem to think it draws its premise from the fact that life arose here.
That is incorrect, though you appear not to know it.
Answer my questions so that I know you are posting in good faith and I will do so. Cheerfully.
So, are you saying my analogies are incorrect?
Actually you can estimate the probability of any given lotto ticket being a winner if you know the total number of lotto tickets printed, and the total number of lotto winners. The problem with extrapolating that rationale to calculate the probability of a given planet having life on it is that we don’t know how many planets have life on them, or even how many planets there are.
If we knew that there were 1 million planets, we could accurately state that the probability that any given planet has life on it must be equal to or greater than 1 in a million.
If we discover an extra planet we missed previously, we could say the probability of that planet having life on it, without knowing any details regarding surface conditions, would be at least 1 in a million.
Yes I know that logic is incorrect. But for the purposes of this conversation it will suffice. I doubt that increasing the sophistication of an argument here will amount to much.
Also bulls don’t have tits. I think you have the proverbial cow by the penis and totally misunderstand the euphemism.
Yes that was asinine, but you kind of deserve it.
Blake The point I was driving at is that refusing to play just isn’t good enough when you get to this type of question. This is one of those big, brain twisting questions that has so many implications it’s scary. The reason I say hard numbers are irrelevant is because we currently can’t do any better; so we’ve got to go with what we have. Why? Because everyone wants to know what we should do. Science provides us with real answers about the universe, our place in it, and how we should pursue our future as a species. In this question you can sit out if you like but others WILL step in. Notably the religious. Where science refuses to tread is the stronghold of superstition. Finding life elsewhere won’t invalidate god, of course. Nothing can, but it would invalidate any number of special creation hypothesis and relegate a great deal of literalism to antiquity. It has huge implications on how we might expand our species to other planets, and even if we SHOULD be thinking about doing that. It has bearing on our understanding of the definition of life itself. THAT is why you can’t just sit out. It’s fine to say “we can’t really be certain until we find it.”, but the world doesn’t work that way. Funding for research is doled out on the basis of bets and odds, as is public support, and interest in developing further technologies that are relevant.
Science can’t just sit out, because the public doesn’t hear: “We can’t be certain because of a complex logic loop that may invalidate our findings”. They hear: " We are incompetent in our ability to even make a guess." When that happens, science loses support of all types, and we go backwards.
Ok, I’ll answer your questions
Please explain the difference, there’s no point arguing about something if we’re not even using the same definitions.
In response to “You’re saying that there is absolutely no justifiable way to estimate the likelihood of life on other planets, ever, under any set of circumstances.”
I’d appreciate if you could clarify your stance on this. Note, that in my post I was interested in the likelihood of there being life on other planets, not the likelihood of there being life on any individual planet.
In response to “You either have absolutely no idea whether or not there is life out there, or you’ve discovered life out there, and proven it without a doubt.”
Please help me out with this one too. You suggested in a post that you would increase the sample size by looking at other planets with life on them. Of course, once you find such a planet, the question “is there extraterrestrial life?” becomes irrelevant.
I disagree. The Universe positively teems with the organic precursors to amino acids. Including alcohol, formaldehyde, formic & acetic acid, glycol aldehyde , and ethylene glycol, amino acetonitrile, in just the “Large Molecule Heimat” region of Sagittarius B, for instance. Anthracene and naphthalene in Perseus. Etc, etc. That’s not to go into all the other organics in just our Solar System.
Wikipedia describes the antropic principle as a:
Though I would call that a pointless tautology myself. How does that imply that ‘life must arise fast on any planet with intelligent life’? As far as I can tell there is no connection at all, not to mention that you seem to be pushing a philosophical argument as a fact. If I have misunderstood your reasoning please explain.
You are however correct that statistically speaking the speed of the first occurrence of something bears no relation to the probability of it occurring again. It’s not proof of any sort. On the other hand it does open the possibility that given the right conditions life is very likely to happen, it’s not like the earth sat their statically lifeless for several billion years and then suddenly life emerged. If that was the case you could argue that the evidence did show it was very unlikely, but that isn’t the case.
And what is that based on?
Yeah, it does. If you like I will quite where it follows from.
By your argument here, it wouldn’t matter what any sample size for anything was, you could never know the probability of a random sample returning a given result.There’s nothing special about extremely low probabilities in this regard. Even if you sampled 99% of the population you could never know the probability of any future sample being similar according to your logic.
Fortunately that isn’t true. The probability of an event occurring can be calculated relatively easily from a sample with >0 degrees of freedom if the samples aren’t self-selected. Something like a power curve analysis would be the best I could come up with, but there are any number of tests that will tell you whether the probability of obtaining 2 planets out of the number sampled is less than whatever cut off you choose to apply, say 1/10^87.
This is skating on very thin ice. It seems to be saying that scientists should not be honest about what conclusions can properly be drawn from available evidence because the political consequences of that honesty might be troublesome.