No, that’s wrong.
Almost anything we observe or can comprehend is a unique example, and no other objects have the same exact properties.
We can observe, analyze and comprehend a tree (not at 100% yet, but close enough).
There is no unique tree in existence. As there is no unique object existence about anything we can comprehend, humans included.
I have no idea if we are alone or not, but I don’t understand how the question can be anything more than idle curiosity. If we are, in fact, alone, we will never be able to actually prove it. If we are not alone, experience shows that we are nowhere close to knowing and are not going to actually be able to use that information in any way any time soon.
So we have an unanswerable question that has no effect on our lives. It frankly does not matter what the “truth” is n
No, we can not.
Every tree in existence is unique.
estimates of possible life-sustaining planets out there range from a few million to 65 billion (the last one is a dubious estimate from a dubious site.)
the 5-sided pyramid (include the square base) is a naturally occuring shape. in the days of contruction of non- load-bearing structures, the pyramid was a logical choice since it was more stable, and entailed fewer tonnage of material moved as one went higher. don’t under-estimate human resourcefulness.
interesting question. could the industrial revolution have occurred 600 years earlier? you have to consider what happened before victorian england. you’ve had at least one major reformation of the catholic church, at least one rebirth of classical art and philosophy, one science revolution (invention of calculus and analytic geometry,) various discoveries for physics, chemistry and medicine.
can’t answer that one. theirs would have been a technology that defies our own and even our senses.
nothing the allies didn’t have as well.
can’t answer you but it hardly has a bearing on your question (does it?)
probably not.
I kind of think that aliens and time travel (yeah, you can rolleyes at me) could be part of the same idea. Who’s to say someone from the future didn’t travel back in time to the pyramids and show the Egyptians something? That blows my brain less than someone four thousand light years away being as evolved -or better- than we are.*
faster than the speed of light? be still.
*Understanding that not all factors will stay constant
We do know that the probability of life existing is > 0. That is evidence. Now, as to how far beyond zero that is, it is surely higher given that we know of intermediate stages between life and non-life (viruses, prions) as opposed to the simplest entity being a cell.
Assume that there is no unique tree. Thus for every tree, there is at least one other tree for which every property that is true of the first tree is true of the second tree. Because differentiating between the two trees is impossible, there is no way to decide whether there is more than one tree. “There is no unique tree in existence” is thus not a statement amenable to science.
Right. We know the probability of life arising is greater than 0. But it could be 1 in 10^10000000000. If it were that low, we’d probably be the only life in our observable universe.
The problem is that we have exactly one sample, which seems like a lot of information. But if that sample didn’t exist, we wouldn’t be here to observe the sample. So that proves that our sample is a biased sample. So the sensible thing to do is to throw out this sample, since we know it is biased. However, if we throw out this sample, we have no other samples left, which is hard to take.
It seems to me that we could within a few decades find evidence for life on extrasolar planets if we find spectroscopic evidence of free oxygen or other molecules that are only produced by life.
Or we could find evidence for life in our solar system. Then we’d have to figure out whether that life was closely related to earth life. It could be, for instance, that life first arose on Mars, and life on Earth is descended from Martian organisms that somehow managed to migrate to Earth. If that’s the case, then we don’t have multiple samples, only one sample, and so we’re back to square one. But if life on Europa was completely unrelated to life on Earth, then we have very strong evidence that life has a very strong probability of arising, and that a random solar system is very likely to have living organisms on one or more bodies.
But this is all speculation. It seems to me that the speed at which life arose on Earth means that life should be fairly common. But we just don’t know. If you pointed a gun at my head and forced me to bet, I’d bet that life is pretty common. But because of the anthropic sampling bias, I have no way to know if that’s a good bet.
Perhaps someone could clarify what the word “probability” refers to in this scenario. My impression is that the discussion has centered on the probability that other intelligent life exists elsewhere in the universe, but this isn’t something to which an objective interpretation of probability can be meaningfully applied. Either there exists life elsewhere or there does not. We should instead like to quantify the degree of uncertainty attached to that proposition.
With that in mind, I’m unsure what it even means to say that the earth composes our current sample. What is a data point? A planet? A planetary system? A galaxy? Can we demonstrate the degree of comparability between data points – i.e., do we have any idea whether other planetary systems/stellar systems/galaxies are comparable to ours with respect to their suitability for life? Do we even know enough about how the unique circumstances on earth contributed to the rise of intelligent life to make statements about how probable it was?
But we have more data right here than just that life exists. The thing that determines the probability of life beginning, at least partially, is the complexity of the simplest form of life or pre-life. Viruses seem to not be considered as truly alive, yet they evolve - they reproduce imperfectly and are subject to natural selection. Since we have already constructed working viruses in the lab, it can’t be that low a probability. Of course all existing viruses have evolved to be dependent on truly living things. Hell, a small bit of RNA wouldn’t. be that hard to make, and I assume there are simpler self-replicating molecules out there. We don’t know what p is exactly, but I think there is good reason to believe that it isn’t ll that small.
Estimates are made with some reasoning behind them. Given that you have declined to produce any such reasoning, I’m going to have to assume that you just made up a couple of humongous numbers on the fly for which you are now attempting to evade any explanation.
Seriously, how did you get those “estimates”?
The Drake equation is inherently probabilistic. That 50% of stars have planets says nothing absolute about whether any of them have life, but this is certainly more likely than if 1% of stars have planets.
I assume someone has adapted the Drake equation to cover the probability that intelligent life exists within a certain radius of earth. Not hard to do - the number of stars is much reduced, and the ratio of stars with planets might differ from the universal case since stellar population near us is probably skewed in some way. Clearly the smaller the radius the less likely it is that we find life.
Just gotta comment on this. There is no reason to assume that any intelligent race that may exist would have any idea of ethics, much less ethics that mirrors our own. Heck, I’d bet that there are a fair number of humans who, if we located an alien intelligent race, would be all for killing 'em all and taking all their loot (if we could do it).
It’d be nice to think that the Star Trek non-interference ideal is universally held but since we can’t even agree on that ourselves it doesn’t make any sense to assume any other intelligent life forms would follow it.
It’d be nice if the aliens, assuming they exist, are all bunnies and kindness (especially if there are hot alien chicks in bunny suits) but intelligence and tech does not require *our *moral code.
Slee
Viruses are probably not very much like the first protolife, because viruses are obligate parasites on existing cells. So viruses couldn’t arise and evolve until after cells existed.
Now that we have detected extrasolar planets, it seems clear that any given star is likely to have dozens of objects orbiting around it. Back in the old days there were theories that planets were formed by extremely rare stellar near-collisions. If that were true, then there could be a 100 million stars in the galaxy but only thousands of planets. It was considered a Big Deal when they first discovered that pulsar had bodies orbiting it. Yeah, most people thought that planets would be common, but no one knew for sure.
I think this is a pretty interesting argument. But I don’t agree. Couple of reasons:
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The general principle that whatever we see all around us is not all that special, especially that most times we had the idea that we (humans, mammals, animals, life, earth, the sun, the milky way, whatever) are extremely rare or special it’s been proven to be mistaken.
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I do not think that life is “pretty much like us” even here on earth. Life on earth is amazingly complex chemistry and it would be folly to think we could predict what life anywhere else would be like. Though it’s probably a good guess that it would employ most of the more chemically active common elements in the universe. Just like we do.
Both seem to me to point to abiogenesis events not being so uncommon to make us (that is us, the life on earth) the first ever. It’s possible, but even if true, it won’t rule out us meeting alien life some time in the future.
I’ve never heard that the Hebrews built the pyramids. Weren’t they in existence already?
Wrong on both counts.
No, it is not higher, and prions and viruses are not intermediate stages between life and non-life.
Ahhh, no. They evolved *from *living things. They are no more examples of protolife than your eyeballs or any other part of your body that has also “evolved to be dependent on truly living things”. By some standards viruses are the most highly evolved lifeform on the planet. There is certainly no doubt that they are descended form living cells, rather than being some sort of proto-life.
And what is that good reason?
No.
No, and that is the biggest hurdle. We have *absolutely *no idea what teh conditions were for the development of life on Earth. An I mean absolutely no idea. We don’t know if it happened in the ocean, on dry land, in the soil or in the clouds. We don’t know what the atmospheric composition or temperature or energy inputs were at the time. We don’t know if life as we see today is first stage life, or if it is second stage life that was crated by earlier non-DNA life, or if it is third or even later stage life. Life as we see it today may well be descended from clay based life through protein life to lipid life to RNA life culminating in DNA life. And every novel lifeform outcompeted and exterminated its own ancestors. Hell, we don’t even know that life originated on Earth. It may have originated in outer space or even in *intergalactic *nebulae.
Then we can move onto more specific requiremnts, such as the requirement for a large moon which requires a collision between two planets at the precise angle at the precise time. The existence of the moon is an extremely improbable event by itself. Maybe only one in a trillion planets that are otherwise identical to Earth even have moons. And that is just one small factor at play.
And those aren’t fanciful theories I just made up. Those are all accepted hypotheses published in the premier journals in the field. When I say that we have absolutely no idea, I mean that we have absolutely no idea. The experts in the field can’t even resolve whether life even originated on Earth. Those who do champion a terrestrial origin can;t resolve whether the first proto-life was even organic. There are seriously those who believe that he first evolving organisms were clay beds or crystal micropores. And those who do champion an organic origin can’t resolve whether the first life was protein, nucleic acid, lipid, micropore or even more exotic material.
We simply have no idea what the conditions were for the origin of terrestrial life.
but even if we will never know exectly how life on earth could have started, terrestial formation of life does not violate physical laws. it is possible, logical.