Sometimes a picture is worth thousands of words

[Luzr]

It's because FTL is truly impossible, and interstellar distances are too far.

You dont need FTL. All you need is generation ships and an energy source capable of keeping them going for a few decades. Which brings us to that other topic again...

Anyway, if we imagine a travel time of 150 years. At 0.1c you can travel 15 lightyears in that time. There are 40 star systems within that distance from us. It is not completely unlikely that there is a planet within the goldy locks zone in one of them.
Accelerating to 10% of lightspeed "only" takes a little more than a month at 1g constant acceleration.
So most of the travel time would be spent at the desired speed.
A constant one g acceleration for a month does not seem completely inconceivable to me. We would still need several technological break throughs, but it is not unimaginable technology.
So in theory the colonists of a very advanced civilization should be able to reach other stars and colonize them.
So if we were to spin this further. You travel 150 years, colonize the planet and repeat the traveling after another 200 years or so.
Then you cover a radius of 15 lightyears every 350 years. So you can "cover" a sphere of some 30,000 lightyears in diameter within "just" 350,000 years (of course the arm of the milky way is only 6000 lightyears wide). From a cosmic point of view 350,000 years is not a very long time. At that rate they could have colonized most of the galaxy within 1 million years. Double the time and make it 2 million years. That is still a very short time, in cosmic terms.

Agree or Embryo Colonization. There is no reason that an intelligence on our level could not easily colonize the galaxy within a few million years.

Actually, it sounds pretty stupid even at this level that we should colonize in biological form... Send silicon (or its future replacement), not DNA...

W.r.t. to Fermi paradox, IMO not quite unlikely explanation is given by Ian M. Banks: There are MANY civilizations in the galaxy. Those most advanced consider "exponential colonisation" immoral and actively act to stop it. That sounds quite plausible to me (of course, if we accept that intelligent life is not rare).

That explains "why we have not met them".

As for "Why we do not hear them on radio?" is the simple one - even at this tage it looks like civilisations use long range radio waves over only short period of time, like 200 years.... Unlikely that we catch that unique period...

[seedload]

It is surely an arguable point and the line at which someone draws it will be subjective, but for good reasons I would say that unless I found a species that farmed its own nutrients, rather than plucking them from the environment, then I would tend not to associate that with 'intelligent life'. In other words, I would feel alone if not in the company of people who understood the necessity of, and relied on, farming. I do not see any other useful delineations that uniquely describe the differences between 'animal life' and 'human life'. Does anyone have any other definitions that they think are meaningful delineations?

Probably any race that controls and manipulates energy (ie fire). Using fire also implies the ability to transfer the knowledge of fire to others. A hunter/gatherer race that sits around an open fire telling stories all night would qualify even if they don't plant food.

[chrismb]

It is surely an arguable point and the line at which someone draws it will be subjective, but for good reasons I would say that unless I found a species that farmed its own nutrients, rather than plucking them from the environment, then I would tend not to associate that with 'intelligent life'. In other words, I would feel alone if not in the company of people who understood the necessity of, and relied on, farming. I do not see any other useful delineations that uniquely describe the differences between 'animal life' and 'human life'. Does anyone have any other definitions that they think are meaningful delineations?

Probably any race that controls and manipulates energy (ie fire). Using fire also implies the ability to transfer the knowledge of fire to others. A hunter/gatherer race that sits around an open fire telling stories all night would qualify even if they don't plant food.

You are saying there is no reason that we could not colonise space. I've given you plenty, and you then say that man has discovered fire. So what?

[seedload]

Agree or Embryo Colonization. There is no reason that an intelligence on our level could not easily colonize the galaxy within a few million years.

Not sure how you come to that conclusion! The reason could be that it is practically impossible to generate enough energy to propel a spacecraft a sufficient distance. Seems a pretty substantial reason to me. Plus that anyone travelling a long way may require radiation shielding greater than that which is practical to put on board a spacecraft. Plus it may not be practical to grow enough nutrients to self-sustain those on board. Plus, &c. &c....

I think what you mean is; there is no reason, according to science fiction, that.... &c....

Embryo Colonization I said. Robots to grow our biology on other worlds. Your particular examples of obstacles apply more toward generation ships than to my suggestion. There are a bunch of problems with mine too, don't get me wrong. Just not the same problems you were pointing out.

[seedload]

It is surely an arguable point and the line at which someone draws it will be subjective, but for good reasons I would say that unless I found a species that farmed its own nutrients, rather than plucking them from the environment, then I would tend not to associate that with 'intelligent life'. In other words, I would feel alone if not in the company of people who understood the necessity of, and relied on, farming. I do not see any other useful delineations that uniquely describe the differences between 'animal life' and 'human life'. Does anyone have any other definitions that they think are meaningful delineations?

Probably any race that controls and manipulates energy (ie fire). Using fire also implies the ability to transfer the knowledge of fire to others. A hunter/gatherer race that sits around an open fire telling stories all night would qualify even if they don't plant food.

You are saying there is no reason that we could not colonise space. I've given you plenty, and you then say that man has discovered fire. So what?

Dude? You changed the topic. You ASKED for other peoples meaningful definitions of intelligent life. I responded with mine. Your's was 'farming'. Mine was 'fire'. Your QUESTION and my RESPONSE are unrelated to the colonization issue - which I wasn't responding to. That is why I quoted what I was responding to. Jeez.

[seedload]

Agree or Embryo Colonization. There is no reason that an intelligence on our level could not easily colonize the galaxy within a few million years.

Actually, it sounds pretty stupid even at this level that we should colonize in biological form... Send silicon (or its future replacement), not DNA...

I don't think that we will abandon our biological form even if abandoning our biological form is possible. Just my conjecture.

[chrismb]

Dude? You changed the topic. You ASKED for other peoples meaningful definitions of intelligent life. I responded with mine. Your's was 'farming'. Mine was 'fire'. Your QUESTION and my RESPONSE are unrelated to the colonization issue - which I wasn't responding to. That is why I quoted what I was responding to. Jeez.

Sorry. I thought the thread had moved on to the issue of colonisation.

On that [older] point, fire might be pretty [too?] easy on other planets, and might even form part of the way the most primitive extraterrestrial species get by, if they are oxygen-atmosphere based organisms at all.

[seedload]

Sorry. I thought the thread had moved on to the issue of colonisation.

NP. I believe that your post was bracketed by the issue of colonisation.

On that [older] point, fire might be pretty [too?] easy on other planets, and might even form part of the way the most primitive extraterrestrial species get by, if they are oxygen-atmosphere based organisms at all.

Yeah, no, you are right. Fire specifically is not really my conjecture, but rather a terrestrial example.

The ability to manipulate energy via an intentional process that is not part of your your own natural biology is my postulation. I didn't want to rule out hunter gatherers. But, as you point out, a natural process could closely approximate what I am looking for.

As to farming, I can imagine some sort of evolved symbiotic relationship of primitive species that very closely resembles farming. So, like my fire postulation, something very similar to what we are using to distinguish intelligence can just naturally occur.

I think in both our cases we need to make a judgement call based on intent and the ability to pass the knowledge to future generations.

[Luzr]

Agree or Embryo Colonization. There is no reason that an intelligence on our level could not easily colonize the galaxy within a few million years.

Actually, it sounds pretty stupid even at this level that we should colonize in biological form... Send silicon (or its future replacement), not DNA...

I don't think that we will abandon our biological form even if abandoning our biological form is possible. Just my conjecture.

What is "we"?

Of course, part of "we" will insist on this. Meanwhile, other part of "we" might encode humanity into digits and send it to colonize.

My guess is that "digital" party would be more sucessfull. Just my conjecture, of course.

[Skipjack]

I dont know who said that first, but one thing that I know distinguishes humans most from animals is cooking. I think the phrase was "warm food is the key to culture".
Of course for that you need fire again. So IMHO Seedload was pretty good with fire. Most animals are affraid of fire. It is an instinctual reaction.
Fire means danger. However we humans learned to control and use it and we lost our fear of the fire. In fact, it meant protection and savety for us.

Not sure how you come to that conclusion! The reason could be that it is practically impossible to generate enough energy to propel a spacecraft a sufficient distance.

Uhm what? We are in space, you accelerate something, it keeps moving forever. You do not have to keep accelerating it. As I said earlier, 1 g for a little more than a month and you reach 0.1 light.
Given enough effort we probably could even do this now. It would be incredibly expensive and it would require a lot of money and resources, but really all you need is a sufficiently large spaceship with enough fuel.
Mass also solves the shielding problem.
You can use the fuel and water tanks for shielding.
What you do need is a good energy source. I do believe that a sufficiently large conventional nuclear reactor, or multiple conventional nuclear reactors would suffice.
To me it is not a matter of whether it can be done, but whether it can be done with a reasonable amount of effort. And currently nobody would be willing to take that expense. However if mankind was in danger of becoming extinct because of some cosmic catastrophy and if we knew of a place to go to, I am sure that the money would come up.

Seems a pretty substantial reason to me. Plus that anyone travelling a long way may require radiation shielding greater than that which is practical to put on board a spacecraft. Plus it may not be practical to grow enough nutrients to self-sustain those on board. Plus, &c. &c....

For shielding see above. It is again a matter of practical versus actually doable. Just because it would be very expensive and unfeasible to do right now, does not mean that it can not be done at all.
E.g. SSTO RLVs are definitely possible with todays technology, but they would be huge and expensive to build, with comparably little payload. At least without smaller technological breakthroughs in some places (not very many needed, some will argue that it would already be feasible).
Again, it is a matter of practical versus undoable.

Actually, it sounds pretty stupid even at this level that we should colonize in biological form... Send silicon (or its future replacement), not DNA...

Uhm what would be the point of that? The human species is biological. I am not with Kurzweil and co. I think their ideas are stupid.
Humans are not just defined by electrical signals in their brain, there are also complex chemical processes that are partially triggered by parts of the body and even by chemicals produced by other people. You take all of these factors out of the equation and reduce the human to his brain and you loose a big part of his personality.

Those most advanced consider "exponential colonisation" immoral and actively act to stop it. That sounds quite plausible to me (of course, if we accept that intelligent life is not rare).

Uhm, I doubt that an uncompetitive species has what it takes to evolve and survive. Nature is a competitive environment. We exist because we are competitive and strive to be better and stronger than other humans and other creatures. Beings that are not competitive will die out, because they will quickly be dominated by those that are competitive.

As for "Why we do not hear them on radio?" is the simple one - even at this tage it looks like civilisations use long range radio waves over only short period of time, like 200 years.... Unlikely that we catch that unique period...

I agree on that one. I have also heard another quite plausible explanation that says that radio waves from our small transmitters will quickly dissipate (after a few lightyears) and disappear into the big cosmic background noise. This also seems plausible to me.

[chrismb]

Just because it would be very expensive and unfeasible to do right now, does not mean that it can not be done at all.

I am beginning to lose all faith [if I had any] in the ability of people to progress a logical argument...

I did not debate it couldn't be done, but that it wasn't the case that there are no reasons that it is not easily done.

The point above that I responded to was the claim that there was "no reason that an intelligence on our level could not easily colonize the galaxy", and where I traversed that by pointing out that there are current, extant, reasons why it is not so, you say 'but it might be possible'! You have confused a 'reason' with a '[double-negative] speculation'. This is how religions start. ("...just because no-one these days comes back from the dead, it doesn't mean that it couldn't happen"...&c...)

The reason could be that it is practically impossible to generate enough energy to propel a spacecraft a sufficient distance.

Uhm what? We are in space, you accelerate something, it keeps moving forever. You do not have to keep accelerating it.

OK, I recognise where you are with that statement, I'll agree with you that to be precise [but was thinking I might not need to] I should've said something like "enough energy to propel a spacecraft to a sufficient velocity for humans to survive an interstellar journey"

[CaptainBeowulf]

I'm not sure the framing is clear. An intelligence on our level or on our current level technologically?

I expect that, without getting more intelligent, we will still advance significantly in terms of technology over the next few centuries. Of course, if Kurzweil et al. are correct, our technology will also make us more intelligent, but, leaving that aside, we can probably make a lot more innovations without becoming smarter.

I tend to think this way:

1. At our current level of intelligence and technology, colonizing space - even over interstellar distances using generation ships - is possible. However, the benefits don't appear to outweigh the costs to the average person/politician, so it won't happen.

2. At our current level of intelligence, but with a few more centuries to innovate, space colonization may become much more feasible, and will happen because the people who want to do it will be able to afford to.

There is really no need to break the laws of physics as we currently understand them. I'm not entirely sure that FTL travel and its time travel implications are impossible (could UFOs actually be people from the future?), but there's no need to invoke them.

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As for intelligent dinosaurs, to my understanding most paleontologists believe that we only find a fraction of the species that actually existed. Most bones never fossilize. Many fossils don't survive geological events such as erosion of fossil fields into rivers/lakes/oceans. So as with many things, we can't say it's impossible. There's just no evidence that any dinosaurs smarter than birds existed. Velociraptor type dinosaurs were quite smart, like birds of prey... but not on par with a human-level intelligence precursor, like a great ape.

I don't really know about how most technological artifacts would decay, maybe someone knows more and could comment? Nonetheless, my impression is that things like concrete, asphalt and brick would break up within several tens of thousands of years. Wooden or other organic implements would disappears in mere thousands.

Plastics and metal alloys would last at least an order of magnitude longer than other things, so maybe 100,000s of years to millions of years. But tens of millions of years?

Stone structures like the pyramids would get pasted by things like glaciers during ice ages, or simply be carried off into the oceans or toppled over by rising mountains due to plate tectonics.

Stone tools might last for millions of years, but after tens of millions of years of getting tossed around with other rocks and exposed to typical erosion mechanisms? They might look like any other small rocks or pebbles by now.

Can anyone say for certain that any evidence of our civilization would exist in 65 million years from now? 1 million or even 10 million years from now, I would say yes, but 65? No idea. It's plausible it might not.

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Intelligent life evolving quickly:

Did it really evolve in 3 million years? Evolution is generally neutral to any given trait. Intelligence may or may not be selected for, depending on the environmental conditions in which a species finds itself.

However, isn't there a general trend towards larger brain sizes, and even towards greater intelligence even when the brain size stays the same?

From what I've read, most dinosaurs are supposed to have been equivalent to the dumbest birds around today. Supposedly the smartest birds are a lot smarter than them.

Generally speaking, most species of dinos, birds, proto-mammals (therapsids or whatever they were called), and mammals seem to be smarter than most species of fish or reptile. Yes, there are things like sharks, but still...

And generally speaking, there seem to have been a lot more large-brained placental mammals than marsupial ones.

Finally, monkeys were developing larger brains for several tens of millions of years. I think the first proto-great apes emerged from monkeys around 25-35 million years ago.

Basically, the true rapid burst in intelligence happened in the last 3 million years... but it may not be accurate to say that it could have happened any time in the hundreds of millions of years before that. Nothing already smart enough to be the baseline for that rapid advance may have existed before 3 million years ago.

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Mass extinctions:

I can see how mass extinction events could either help or hinder the emergence of intelligent life. I think it really depends on the specific ecosystems which are affected, and the specific animal species that are killed off/allowed to emerge.

[hanelyp]

Of course, if Kurzweil et al. are correct, our technology will also make us more intelligent, but, leaving that aside, we can probably make a lot more innovations without becoming smarter.

You could argue we're already there. The computer I'm using allows me to access and manage vast quantities of data that would otherwise be beyond the practical capacity of my brain to keep straight.

[krenshala]

E.g. the dinosaurs could have eventually evolved into more intelligent beings.

Or, and that is funny line of thinking: Perhaps they did. Would we know today? 200 millions of years is long enough to cleanup all traces.

Please tell me folks, what is the physical trace of "intelligence"? For all we know there have been 50 sapient species on this planet, only one of which chose to go the "technology" route. What trace would a race of a-technical genius philosophers leave?

I think Douglas Adams said it best:

Man has always assumed that he was more intelligent than dolphins because he had achieved so much...the wheel, New York, wars and so on...while all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man...for precisely the same reason.

My opinion is that we may be the only (relatively) high tech using sapients on the planet, but we are not the only sapients. Sure, its an opinion based on observed behaviors not rigorous testing, so its far from an "informed" opinion. But the more I see and learn, the more I believe it to be true.

Likewise, it is entirely possible there were other sapients on this planet before the last major extinction even 64M years ago. Of course, I think that event is what allowed us to achieve our current position in the food chain.

As for life on other worlds -- I think it is arrogant (anthro-centric?) to think only this one planet has it. Intelligent life is a more complicated matter, as you guys have already agreed. The chances of intelligent life forming and surviving to teh point we have reached are astronomically small, and yet, with an astronomical number of bodies on which to "try", random chance says it is unlikely to only have one success.

The others might include carbon-based-oxygen-using forms, like us. Or they might have formed in what we refer to as the goldilocks zone of heat from the parent star (were water is liquid). Or they might be something completely different (pure gas held together magnetically? would a human even be able to recognize that as an intelligence, let alone communicate with it?).

Now, if you asked me whether I thought we'd meet an alien race that looked like a human, and could be mistaken for one, I'd laugh and say, "Unlikely!"

Ignoring all the probability of their existing, why don't we "see" them? I can think of a number of reasons this might be, assuming they exist.
They are ...

• ... already here, as WE are the aliens! (unlikely, but a possibility that should be considered)
  ... monitoring us (as a control?) in a science experiment
  ... ignoring our planet because better ones are available
  ... using comms we can't detect, either due to direction, range, or type (ignoring the issue of timing, though it should also be considered)
  ... are busy with something more important to them than a backwater planet 3/4 of the way out from the galactic core (aren't what we consider useful resources supposed to be better closer to the center?)

If I put more effort into it I could come up with others,, but these are the ones that come up spur of the moment. These all assume "they" and humans are coexisting in the same time period.

[edit] And in reference to CaptB's post above, I thought I'd drop a link to a page about a crow.

[Luzr]

I dont know who said that first, but one thing that I know distinguishes humans most from animals is cooking. I think the phrase was "warm food is the key to culture".
Of course for that you need fire again. So IMHO Seedload was pretty good with fire. Most animals are affraid of fire. It is an instinctual reaction.
Fire means danger. However we humans learned to control and use it and we lost our fear of the fire. In fact, it meant protection and savety for us.

Not sure how you come to that conclusion! The reason could be that it is practically impossible to generate enough energy to propel a spacecraft a sufficient distance.

Uhm what? We are in space, you accelerate something, it keeps moving forever. You do not have to keep accelerating it. As I said earlier, 1 g for a little more than a month and you reach 0.1 light.
Given enough effort we probably could even do this now. It would be incredibly expensive and it would require a lot of money and resources, but really all you need is a sufficiently large spaceship with enough fuel.
Mass also solves the shielding problem.
You can use the fuel and water tanks for shielding.
What you do need is a good energy source. I do believe that a sufficiently large conventional nuclear reactor, or multiple conventional nuclear reactors would suffice.

I guess the main often overlooked problem is that all of this have to be working for millenia. Which means today ship would have to be really big to take away the complete technological base AND resources to rebuild any device onboard after it fails (and everything has to be there 3 times to achieve acceptable redundancy).

Those most advanced consider "exponential colonisation" immoral and actively act to stop it. That sounds quite plausible to me (of course, if we accept that intelligent life is not rare).

Uhm, I doubt that an uncompetitive species has what it takes to evolve and survive.

That is not about competition.

Even today, most people do not compete by breeding. I guess at least for humans, competitivness is about status seeking, not breeding. And even in competitive human environments, there are moral rules that prohibit some actions. I guess "do not have too many children" is quite powerful meme in many countries...

Nature is a competitive environment. We exist because we are competitive and strive to be better and stronger than other humans and other creatures. Beings that are not competitive will die out, because they will quickly be dominated by those that are competitive.

I guess that holds for all life before civilisation. Civilisation works a little bit different, rather spreading memes than genes....