The humanoid body - wierd design, but the only way to become truly intelligent

[Christopher]

A recent discussion in the Space News thread spiraled a bit out of control, so I thought I make a new thread just for that discussion.

My point is that tool use that makes higher Intelligence possible or even desireable and that the humanoid body is the best design for tool use.

 

Among all the animals on earth the human body is a extremely odd design. Every other species on the planet is comparably either stronger, faster, better swimmer/flier, more posionous and/or better equipped with natural weapons and defenses. Or they outnumber is by a factor of thousands to millions.

 

There was once a demotivational picture of a angler on a boat having caught a shark, with the following subtitle:

"Remember. If it was not for the Gadgets it would be the other way around!".

Just recently I realised a proper response: "True. But by the same logic without teeth and the ability to breath water the shark would not have survived or existed either."

The human body is designed for tool use, same way as the shark for swimming and breathing in water and hunting stuff in the sea using his teeth.

 

 

Evolution is against Intelligence:

As far as I can tell, Evolution is against intelligence. No species can afford to be smarter then a certain amount, based on it's ecological niche. The most successfull species have no Central Nervous Systems. Even a lot of stuff visible to naked eye has no or only a very primitive CNS. Brains are quite literally overrated.

 

A species must proove against the selective pressure that it's intelligence matters. Inteliigence has massive tradeoffs in the birthing, growing up and metabolism departments. The only way a species can develop increasing intelligence is to make it usefull for day-to-day survival. Wich means having the ability to use tools, make tools and make and use perpetually better tools.

Tool use and intelligence go hand in hand.

 

 

Best adapted is not equal to most complex:

Darwins Laws state that the best adapted is the best design. A common misconception is to asume it means the most complex is the best. Totally wrong.

Just like intelligence, evolution shuns needless complexity. That upright walking means no more need for the tail? Let's get rid of that, useless energy hog and predator vulnerability.

That amoeba visible to the naked eye has no brain? Guess what, it needs none!

 

But then why do we still have that (apparently) useless Appendix? Propably, it's existance does not mater that much. We are talking about something a thousand times smaller and less problematic then a tail or a brain. And our body was not quite selected for a lifespan where it would pose a problem anyway (see below).

If there is ever a mutation that get's rid of it totally, would that constitute an actually relevant evolutional advantage?

 

 

Humanity is out of Evolution and out of it's Environment:

The modern human body is largely out of it's environment.

For 2 Million Years it evolved towards hunter & gatherer with an average lifespan of around 18 Years. That is the environment our body expects to find when it comes out of another human. That is what it is designed to life in. And it is not even close to reality.

 

Current data indicates we started something as revolutinary as "settling down" and "growing plants" a mere 10 000 Years ago. Now we are doing this full time, practically everywhere on the planet.

We exceed the evolutinary selected for lifespan by a factor of 5-8.

Instead of the Hunter&Gatherer lifestyle we life a Agricultural Lifestyle. Our body, our instincts are literally not designed for the life we live.

 

10k Years is not even remotly the timespan a species needs to adapt to such a mayor shift in environment and living conditions. And we keep changing it more every year.

We don't even know what "natural" behavior and fitness for a 30 year old is, because we are not even supposed to get that old in the first place!

 

 

Drawbacks of Intelligence:

I said intelligence has cost. Time to list them!

- A high body/brain ratio means higher energy demand from the brain. Unlike muscles or stomach, the brain does not directly contribute to survival. It is not nessesary like skin or a liver, as many species prooved for millions of years. Purely biologically it is "dead weight".
It has to pull it's weight or that mutation with the 5% more intelligence would never have gone mainstream (and lead to the next 5% more brain power). If smarts do not make you a better lifeform, dumber but simpler ones will overturn you.

 

- it adds extra complexity to put the brain far up in the body in a vulnerable, bony extrusion. We know the brain does not react well to the body being upside down, so it propably needs the lower blood pressure of being "up". There is also the advantage of close lines to the eyes, ears and nose wich are better placed high up and front then low or at the back.

 

- Sleep. We don't know why we sleep or why so long (1/3 of the day). We could sleep less, as we don't need to ration our energy quite as much. It is said the body only needs about 1 hour of rest anway. Mostly sleep seems to be there for our brain.

So it's propably a tradeoff of our intelligence too. 8 hour sleep per day is not a usefull evolution by any measure I know, so it must be a tradeoff that was just worth it.

 

- most importantly perhaps, it is the reason we have such a long phase of "useless" childhood.

Most other species on the planet are able to walk with the herd or mother within hours to days of being born. We need about 1 decade to get that far. And we are genetically only expected to life about 8 more on average (that we life longer is a fluke).

 

One decade of utter helplessness against ground based predators and dependance on later lifecycles is one big cost of being as smart as we are.

Just think if a Dolphin or Dog had such a long childhood compared to it's lifespan. He would have died from predators and his higher intelligence would never have caught on.

And even if he was that smart, he could not use those smarts for tool use.

 

 

Drawbacks of upright walking:

Walking upright seems like the most natural thing to do for us humans. But as far as locomotion goes, that is not a good design. Only flight is worse.

 

- Just ask any roboticist about making a 2 legged robot and he tells you the design is just terrible. 4-6 legs is soo much easier, even if we have a harder time wrapping our heads around it.

Only reason we still focus on making 2 legged robots is because our Environment is designed for 2 legged locomotion. Making anything else would be like bringing wings to a diving contest.

 

- It means we only have 2 legs rather then 4. So the legs will be under more severe load, allowing us a lower speed/mass ratio. It also gives us less redundancy - a dog with only 3 legs can still walk, a human with only 1 not (without tools).

And nope, trained humans do not count. Don't compare a race human or weight lift human to an average ape or leopard. Compare it to a race leopard or weight lifting ape!

 

- It means our entire locomotion is highly dependant on some extra organs near the ears/brain. Without our Sense of balance we would just trip over. While 4 legged species have that too, thiers is a lot less complex, developed and relevant. Many 4-legged species can stand while sleeping, that is how simple thier sense of balance is.

 

- our women need breasts, wich makes the thing even harder. Scientists are not quite sure why we have breats or are atracted to them. All other species use butts as center of reproductional attention.

The best theory I heard so far is: "With upright walking, the butt left the field of vision. So breasts had to develop as the new atractional center".

Half our species needs extra weights on the chest that make balance and the mechanic of locomotion even harder for them.

 

- If you think having breasts is bad for your mobility and possibly your spine, pregnancy while walking upright is even worse!

In the later phases of pregnancy women might well be unable to defend themself and have strongly limited mobility. Most 4-legged critters maintain thier mobility until shortly before birth.

 

It has one big advantage: It frees those 2 front legs for dedicated tool use. In species that don't need them for locomotion (flight or walk) or tool use (not enough brain), they recess and might eventually vanish.

While it is true that apes can use tools too and still walk on all 4, can they use every tool we make as good as we?

Thier throwing range is high limited, as is thier manual dexterity. The tools they can use is the limit of what thier body allows to use easily. Hence thier inteliigence is the limit of what evolution allowed for thier body form.

 

 

Why aliens will likely be humanoid:

Human level intelligence needs a roughly humanoid form.

If we ever find aliens (or they us), chances are good they will actually be humanoid in shape. And they might very well be carbon based oxygen breathers too.

Not because the design is so awesome. Not because something divine dictated it. Not because our form is so special. But because it is so not-special and propably the only longterm viable design for tool use.

 

As terrible an animal the human body is, as great a tool user it is.

True intelligence (on our level) needs full fleged tool use to properly develop. Without that, it is not worth the effort to evolve that/is selected out as needlessly complex. If you got other natural advantages, you do not need a good brain.

As nice as it would be to have 4 arms or 2 arms, 2 legs and wings, once a species goes onto the path of tool use it does not need them anymore. And if it has them, it does not need intelligence.

[procyon]

I will agree that tool use is an advantage.  And that any other race we come into contact with with either be a tool users or considered an 'animal / plant / etc'.

 

But I doubt that bipeds will be the 'common' form for a tool user.  I would expect that it will either have or have developed limbs of some fashion that are devoted to tool use.  Otherwise tool use will not become a significant advantage.

 

But I will take issue with the thought that we are not well adapted for a 'physical' lifestyle.  We are.  Most are simply to sedentary to see it anymore.

 

Bipedal movement isn't a detriment.  It allows us to see over brush and grasses.  Two thirds of our food when we were hunter / gatherers came from gathering - so a better vantage was an advantage.  It also makes it easier to spot prey animals and see predators coming.

 

We are still good climbers, even at early ages (but not as quick to do so as other animals).  Just watch a couple 5 years olds on the monkey bars or with an apple / pine tree to climb and you will see how they would have avoided a large number of predators.  So human children are vulnerable for around 4-5 years, but this isn't significantly different from many other larger animals.

 

We are also not as fast, but we have one of the best circulatory systems designed for long distance movement at speed.  No hair to allow rapid cooling.  Only two limbs to devote energy to for said movement.  Many other circulatory adaptions to allow us to maintain higher levels of exertion for extended periods.  Even my 11 y/o daughter can run 2 miles with me in the morning.  We aren't bears or tigers - we are pack hunters that ran our prey to ground. Watch old films of how the Maasia hunted and you will see how it works.

 

Oh, and our brain not liking being upside down is just a simple adaption to our current body design and not a 'has to be' thing.  Just remember - you spent months with your head down inside your mom before you were born quite happily.  We just adapt to being right side up after we get out and lose the vascular strength to remain upside down.  Just like if you grow up to sit at a desk all day you lose your ability to run around all day long that you had as a teenager.

 

Our 'design lifespan' is actually closer to 40 years, not 20.  Just long enough to ensure a next generation reaches reproductive age.  The most obvious sign is our eyes, which begin to lose the ability to maintain close resolution (meaning you get to buy reading glasses even if you don't have eye problems) when you reach your fourth decade.  And research shows that even thousands of years ago most men who survived their childhood (women also had to survive childbearing years) tended to live between 40-60 years or more.

 

I expect that any 'life' we meet or contact will be a tool user if we are going to consider it intelligent.

But beyond tool use, I doubt that it we resemble us at all.  We adapted to our planet and environment.  Life that arises and evolves on a moon like Titan may even be carbon based to some degree - but that will likely be all.

 

But I agree that this should have been split off a while back.

[Lord Liaden]

We became bipeds because our ancestors were quadrupeds, so walking upright to free our arms for tool use, left only two limbs for locomotion. Birds had to go the same way to develop wings.

 

A species from another planet might have evolved from creatures with six or more limbs. And/or with them arranged radially rather than bilaterally.

[Lawnmower Boy]

i) Bipedalism is very common, even primordial.

 

Recall that animal life belongs mainly to the Phanerozoic Eon (541 million to present). The modern eon begins with the Paleozoic, at the beginning of which, the Cambrian sees the well known explosion of complex, multicellular animals. This well-known, very brief period, may have seen the evolution of many body forms, including many no longer extant, in the course of eighty million yers froma single ancestral form of protist.

 

The synapsids and archosaurs, which evolved, the former definitely, the latter possibly as early as, the  Permian period (298--252 million), are the ancestors of all large terrestrial animals today. Synapsids are earlier than archosaurs, in spite of being the ancestors of mammals. I have seen it speculated that the fact that they were ventilated to breathe and eat at the same time is the key to their modern, colossally mentally challenging ability to walk and chew gum at the same time.  Nevertheless, it is the archosaurs who became dominant during the Triassic, after the synapsids blew their saving throw at the Permian-Triassic Boundary.  Archosaurs are predominantly classified by their ankles (I did not know this!) and the first "bird ankles" appear with the  Avemetatarsalia in the Carnian age of the late Triassic. The Dinosauria are, in descent from this, classified as those archsaurs which hold their legs erect under their bodies, but only some of them are bipedal, the therapods, which are extant from the earliest phases of dinosauria, that is, from the above-mentioned Carnian, from 231 million years ago. From there down to ostriches it is pretty much a continuous line, including a steady diminution of size which may have been linear without regards for the Cretaceous-Paleogene extinction event.  

 

Hold that thought (about the extinction event) for a second. What's important here is that, roboticists' difficulties notwithstanding, bipedalism has been common in terrestrial life for half of complex animal life's evolutionary history on the planet. Roboticist, heal thyself.

 

(ii) Tool use, like bipedalism, is very common amongst the complex animals. It is seen, for example, in thirty-three different families of birds. Tool creation is more contentious, but it suffices for now to note the Olduwan cultural horizon, which is associated with Australopithecus and dated to 2.5 million years ago. Intentionally shaped stone tools have been in use for approximately one half of one percent of the history of of complex animal life on this planet. 

 

iii) Are these adaptations tardy?  Consider that we are apparently too unsure of the origins of ruminance to assert its chronology on Wikipedia, the Cervids , Girafidae and Bovidae arose over the course of ten million years during the Miocene (30 million to 20 million). The ability to digest cellulose through rumination has been present amongst the complex animals for only 6% of the history of that lifeform oon this planet. The implications of this are not small. It is quite possible that ruminant biology is crucial to forcing the modern ice age cycle.  

 

But, rumination is only as effective as it is because of the evolution of plant life incorporating phytoliths, notably the graminae, or grasses, which evolved along with the other flowering plants at the end Cretaceous. Before we got all het up about asteroid strikes, the evolution of the monocotyledon was often proposed as the cause of the extinction of the dinosaurs. Now that we know that we are talking about the extinction of the large dinosaurs only, I am more sure than I ever was that this old hypothesis deserved a revisit. Again to summarise, the flowering plants have only been present for a little above ten percent of the history of complex animal life on this planet.

 

But, the monocotyledon were not the first complex vegetable life forms on this planet. The gymnosperms  evolved in the late Carboniferous, about 320 million years ago. These woody plants rapidly displaced the earlier lycospids in the Carboniferous Rain Forest Collapse.   The lycopsids are notorious for their remarkably thick lignin coats ("bark"), well attested in the fossil record in the Coal Measures. While the collapse is now explained by climate change, the fungi, in spite of being very ancient indeed (to 1.46 billion years ago, perhaps), evolved the Ascomycota, the largest phylum of fungi, in the late Carboniferous, and although the ascomycota exhibit numerous evolutionary adaptations, the relevant one here is the ability to attack lignin. Various evidence has been adduced to show that the Permian-Triassic Boundary was an "Age of Fungus," and if you do not imagine an apocalyptic landscape of vast spider webs wrapping skeletal forests of mushroom-mounded, rotting lycospids under a dark and burning sky, rapidly cooling towards an ice age, then I don't want to know you, man. (Just because my potted history blames the ruminants for the modern ice age cycle doesn't mean that they're the only culprits.) Just to summarise, mushrooms have only been present for half of the history of complex animal life on this planet. 

 

To summarise this very long bullet point, many important evolutionary developments in the history of this planet have been "tardy."

iv) Because it deserves its own bullet point, even if it is a natural conclusion to be drawn from the above, evolution is also an "arms race" in which a whole series of killer evolutionary adaptations, ones often so successful as to destablise the global climate, have arisen in an at least somewhat natural succession.

 

v) Many of the points made about the "problems" of intelligence are just strange. Bats do just fine hanging upside down all the time. Cats sleep longer than people. In fact, in general, small animals sleep longer than large animals, with the required amount of sleep a function of body weight, not brain size. So is maturation rate, to an extent. Male elephants have their first musth at age 15, for example. Humans have what seem to be something of an outlier here, and there's an old theory that this reflects a "neoteny," the retention of juvenile characteristics into adulthood, these including big brains. Unfortunately, it tends to be wrapped up with some noxious scientific racism. As for the "secondary sexual characteristics" thing, I'm goint to just leave that one hanging. Except to point you to my last link, if you're not following them all. (It's not Wikipedia, but it is NSFW.)

 

The strangest claim is that evolution selects against intelligence. Because, and I cannot emphasise this enough, there is at least one very successful species in our current biome which has a very high order of intelligence. (Spoiler: us.) There are others which are strikingly intelligent, and the evolution of "conscious intelligence" goes back, depending on who you ask, 2.5 million years or 50,000. It's only meaningful to say that our species has won the lottery if this is "tardy." And it's pretty clearly not. As noted above, we can trace necessary precursor traits for intelligence back to the synapsids. 

[NuSoardGraphite]

I follow UFO conspiracy theory pretty heavily (i find it fascinating) and there are some in that field who claim the humanoid form is the gold standaard throughout the galaxy. It will be very interesting to find out if that is true over the coming decades and centuries (i hope we find out before we kick the bucket)

[megaplayboy]

Well, one logical question would be, what kind of physical form, short of technological augmentation, would provide a living being with optimal traits for, say, intelligence/sapience? Support for a larger brain, yes, but what about a more efficient brain/nervous system? What about superior sensory abilities and/or motor skills? Can a bipedal, warm blooded hominid form enable that kind of further evolution? Or is there some form which would tend to do so more easily? E.g., could we "naturally" evolve to be an order or magnitude or two higher on our Sentience Quotient(around +13 at the moment)?

[Christopher]

Bipedal movement isn't a detriment.  It allows us to see over brush and grasses.  Two thirds of our food when we were hunter / gatherers came from gathering - so a better vantage was an advantage.  It also makes it easier to spot prey animals and see predators coming.

 

We are still good climbers, even at early ages (but not as quick to do so as other animals).  Just watch a couple 5 years olds on the monkey bars or with an apple / pine tree to climb and you will see how they would have avoided a large number of predators.  So human children are vulnerable for around 4-5 years, but this isn't significantly different from many other larger animals.

 

[...] We aren't bears or tigers - we are pack hunters that ran our prey to ground. Watch old films of how the Maasia hunted and you will see how it works.

But all other hunter species - especially the pack hunters - stay close to the ground and work out just fine. The only animals that are large a grazers/plant eaters on land.

We needed to have hands before we could ever start being gatherers. If plant mater was the more abundant food source, logic dictates to just become grazers rather then go to bipedal tool use.

If bipedal was preferable over grazing, why are cows and giraffes not bipedal?

 

 

"Oh, and our brain not liking being upside down is just a simple adaption to our current body design and not a 'has to be' thing.  Just remember - you spent months with your head down inside your mom before you were born quite happily.  We just adapt to being right side up after we get out and lose the vascular strength to remain upside down.  Just like if you grow up to sit at a desk all day you lose your ability to run around all day long that you had as a teenager."

The baby brain is much less developed then the adult brain. A human with a fully grown brain (and all the support structure would not fit into another human being.

Simpler, less developed systems are more robust. It is thier nature.

It could even be that the baby brain is prevented from going past a certain "level" by being upside down.

Also there is much less blood in a baby to press down on the brain. Half a liter at 1G exerts a lot less force then 8 liters at 1G.

 

Several times higher force on a much more complex system.

 

We became bipeds because our ancestors were quadrupeds, so walking upright to free our arms for tool use, left only two limbs for locomotion. Birds had to go the same way to develop wings.

 

A species from another planet might have evolved from creatures with six or more limbs. And/or with them arranged radially rather than bilaterally.

Birds can afford bi-pedalism because they are build with low-weight, even if thier wings regressed. Thier leg's must work with much less pressure then we and even then most have very short legs.

 

Even if they evolved from an ancestor with 6 legs, why did they KEEP those extra legs? A centaur combines all the bad parts of bi-pedal upper body (needlessly comlex balance, especally women during pregnancy) and quatrupet lower body (less maneuverable; inability to use ground to make tool).

Centaur designs would propably select towards less long lower bodies until the aft legs become totally useless as they became de-facto bipedal.

 

 

I follow UFO conspiracy theory pretty heavily (i find it fascinating) and there are some in that field who claim the humanoid form is the gold standaard throughout the galaxy. It will be very interesting to find out if that is true over the coming decades and centuries (i hope we find out before we kick the bucket)

As I said, actually the design is terrible. Why else are we the only species on the whole planet that did it consequently? Many species on our planet must have tried getting smarter. We are just the first to survive the experiment.

 

Another way to look at it is that all other forms turned out to be dead ends for further intelligence.

Bird +5% intelligence = worse bird overall

Worl +% intelligence = worse wolf overall

 

The one thing that confuses me most is how Dolphins could afford thier smarts. They are less able to use tools then your average bird (no leverage from the ground). Yet they are about as smart as an ape? How did that happen?

 

Well, one logical question would be, what kind of physical form, short of technological augmentation, would provide a living being with optimal traits for, say, intelligence/sapience? Support for a larger brain, yes, but what about a more efficient brain/nervous system? What about superior sensory abilities and/or motor skills? Can a bipedal, warm blooded hominid form enable that kind of further evolution? Or is there some form which would tend to do so more easily? E.g., could we "naturally" evolve to be an order or magnitude or two higher on our Sentience Quotient(around +13 at the moment)?

As I said, we are out of evolution. So we won't naturally evolve anywhere. Tool use is a cheatcode that breaks normal evolutionary bounds and rules. Once you have it, you only need to develop it and be set up.

 

About evolving from a species that had those traits:

If you are so dependant on your better eyesight/exoskeletion that you don't just loose it as "needless complexity", do you actually have room to become a tool user?

Once you start using the cheat-code, would designs that skimp on these features not be inherently better?

 

"If once you start to walk this path, forever will it dominate your destiny" - Yoda

[Zeropoint]

It strikes me as mildly amusing that someone who hasn't even HEARD OF any intelligent species besides his own is spending so much time claiming that OF COURSE his own species' body plan is the objective best for intelligent life.

 

 

As I said, we are out of evolution. So we won't naturally evolve anywhere.

 

This is incorrect. Are we still reproducing? Yes. Are the offspring genetically identical to the parents? No. Therefore, we're still evolving. It only LOOKS like we've "stopped evolving" because our cultural evolution is far faster than our biological evolution. Yet, new mutations and genetic drift are still occurring.

[megaplayboy]

We are gradually nearing a point where we can control the course and scope of our evolution, though.

[sinanju]

 

 

The one thing that confuses me most is how Dolphins could afford thier smarts. They are less able to use tools then your average bird (no leverage from the ground). Yet they are about as smart as an ape? How did that happen?

 

One theory I've heard recently is the explosive growth in human intelligence (on an evolutionary scale) has more to do with SOCIAL interactions than with dealing with the physical world. We're social creatures, and being able to communicate, to detect (or hide) emotions, motives, and so forth is an advantage--so the ability to read facial expressions, body language, remember past interactions, gauge someone else's truthfulness and trustworthiness and so forth becomes an "arms race" of sort that ups everyone's game.

 

 

 

This is incorrect. Are we still reproducing? Yes. Are the offspring genetically identical to the parents? No. Therefore, we're still evolving. It only LOOKS like we've "stopped evolving" because our cultural evolution is far faster than our biological evolution. Yet, new mutations and genetic drift are still occurring.

 

Yes. We're still evolving. Medicine means people survive and even thrive (and thus reproduce) despite accidents and illnesses that might have killed them before they could do so in the absence of such technology. On the other hand, it isn't only physical traits that evolution works on, it also operates on the behavioral level. Why are we living in the most peaceful era in human history (which it is, no matter how awful the news sounds)? Is it because we've "learned" to be less aggressive and warlike? Or is it because we've spent thousands of years culling out of the most aggressive and non-social members of society? If your culture(s) execute criminals* with sufficient zeal, what you have left is a population in which the desire to be criminal* is either absent or restrained by caution. Are we domesticating ourselves?

 

*"Criminal" of course can mean murder, rape, robbery, theft and so forth--or refusal to do your "fair share" of the work needed for the community to survive, or a refusal to submit to the totalitarian desires of your rulers. Either way, if such behavior becomes an impediment to survival**, then you're less likely to pass on the temperament to behave that way. It's a long, slow process, of course, as is evolution in general; but incremental differences do make a difference over time.

 

**A friend of mine who went to Iraq as part of a mission to help train the new government in running prisons in a more "modern" (i.e., American/western) fashion, saw this firsthand. In our system, if someone is in the prison and no documentation can be found to justify his presence there, he gets released. In Iraq there were a lot of prisoners the reason for whose presence in prison couldn't be determined, but without explicit instructions to release someone, he stays indefinitely--because decades of brutal rule by Saddam Hussein had thoroughly culled the population of anyone willing to show any initiative. That could get YOU imprisoned or executed. And it wasn't just the prisons, my friend saw evidence of this everywhere.

 

Now, this was cultural, not genetic, of course. But I think the principle may well hold on a larger scale, on a longer-term scale.

[procyon]

But all other hunter species - especially the pack hunters - stay close to the ground and work out just fine. The only animals that are large a grazers/plant eaters on land.

We needed to have hands before we could ever start being gatherers. If plant mater was the more abundant food source, logic dictates to just become grazers rather then go to bipedal tool use.

If bipedal was preferable over grazing, why are cows and giraffes not bipedal?

 

Most pack hunters that run down prey (wolves) use scent as their primary sense.  So close to the ground is better.

Hands do help with gathering.  But we aren't the only ones.  And not just apes & monkeys.  Look out your window.  See the squirrels?

How about raccoon?  List goes on.  We aren't the only ones with manipulative forepaws.  Lots of them are still on all fours - but will also use bipedal orientation when advantageous.  So get over the biped fixation as necessary for hands.  It isn't even true on this planet.

As for cows, rabbits, etc - they aren't GATHERERS.  They are grazers.

Standing for them would be counter-productive.

 

 

"Oh, and our brain not liking being upside down is just a simple adaption to our current body design and not a 'has to be' thing.  Just remember - you spent months with your head down inside your mom before you were born quite happily.  We just adapt to being right side up after we get out and lose the vascular strength to remain upside down.  Just like if you grow up to sit at a desk all day you lose your ability to run around all day long that you had as a teenager."

The baby brain is much less developed then the adult brain. A human with a fully grown brain (and all the support structure would not fit into another human being.

Simpler, less developed systems are more robust. It is thier nature.

It could even be that the baby brain is prevented from going past a certain "level" by being upside down.

Also there is much less blood in a baby to press down on the brain. Half a liter at 1G exerts a lot less force then 8 liters at 1G.

 

Several times higher force on a much more complex system.

 

So how about a life form that evolves on a Titan like body, with 0.14G ??

You really are fixated on life only being possible on an Earth-like world.

Which is rather unlikely.

 

 

Birds can afford bi-pedalism because they are build with low-weight, even if thier wings regressed. Thier leg's must work with much less pressure then we and even then most have very short legs.

 

Even if they evolved from an ancestor with 6 legs, why did they KEEP those extra legs? A centaur combines all the bad parts of bi-pedal upper body (needlessly comlex balance, especally women during pregnancy) and quatrupet lower body (less maneuverable; inability to use ground to make tool).

Centaur designs would propably select towards less long lower bodies until the aft legs become totally useless as they became de-facto bipedal.

 

 

As I said, actually the design is terrible. Why else are we the only species on the whole planet that did it consequently? Many species on our planet must have tried getting smarter. We are just the first to survive the experiment.

 And a bird on a Titan like world wouldn't even need to worry about the limits we have of atmospheric density vs gravity's acceleration.  Birds evolved for our world.  Not another.

And why a 6 legged creature that rose up in a centaur like arrangement would have a problem with pregnancy is beyond me.  Just envision that the centaur girl carries the 'foal' in the horse part of the body.  Carrying it farther forward would be silly.

 

And saying we are the only bipeds is just false.  They are found even in the distant past.  Look at any of the raptors in the dinosaurs.  T-Rex, et al.

There are still some today outside primates.  Ever seen a kangaroo ?!

 

As for tool use, that is going to be a requirement.  I just don't see a race contacting another race in interstellar space using their innate capabilities.

[Lucius]

 

Tool use is only one of the benefits of the constellation of traits we call "intelligence" Vitally important, yes, but not the only factor.

 

Language use unlocks the potential benefits of cooperation and communication. A beast can use a distress call and inform the rest of the herd "Predator! Here, right now!" a Human can tell someone "I found the tracks and droppings of a big bear over in the woods towards the setting sun." A beast can communicate the equivalent of "Mommy, daddy, help!" and possibly save itself from being eaten. A Human can say "I tracked that bear to its lair, and there's only one right now, want to come with me and my sisters and set an ambush for it? Enough meat to go around and we can stop worrying about it catching one of our kids if it wanders over our way."

 

And language use doesn't depend on a given body type. There could be aliens with an olfactory language who communicate abstract and complex ideas with pheromones.

 

Probably related to language use, we enjoy the benefits of enhanced powers of memory and cognition. The ability to do things like anticipate the future and plan for it confers survival advantage for the individual and the group. A Human can say "I think we should go kill that bear now, before it finds a mate."

 

And again, I don't think that necessarily depends on a given body type.

 

But aside from the possibility of intelligent, articulate life forms that are not tool users, I don't necessarily agree that only a humanoid form is suited for tool use. The fact that no squid or elephant for example has our level of manual dexterity does not mean that something like a tentacle or trunk could never evolve the equivalent of an opposable thumb, keen tactile sensitivity, and the rest of the complex of traits that enable us to handle objects so precisely.

 

And a few points about details:

 

- Many creatures other than Humans have mammary glands.

 

- Sleep is far from unique to Humans. Even nematodes sleep.

 

- There is no reason to assume that a hypothetical centaur like species would carry its developing young anywhere but in the same anatomical location that a horse does. In fact, I think it very unlikely it would carry that load in the vertical torso rather than the horizontal torso.

 

- For that matter, there is no reason to assume any hypothetical alien species would bear live young as opposed to some other system of reproduction such as laying eggs.

 

Lucius Alexander

 

The palindromedary neither lays eggs nor bears live young.

[procyon]

Oh, and just to be clear Christopher, I really do enjoy this conversation.

I hope I don't come across as to snarky.  I just really love to discuss these sorts of things where there Is no solid, right, answer.

Just folk throwing out ideas and thoughts.

 

It is the one thing I miss about my time as a physicist.  I love my current job in the NICU, but it doesn't leave much time or opportunity for discussions like this.

 

[Lucius]

I agree, it's an interesting and worthwhile topic.

 

Lucius Alexander

 

Then again, I find palindromedaries interesting and worthwhile

[dmjalund]

I once designed a six limbed alien whose middle limbs were the manipulators

[Old Man]

We are gradually nearing a point where we can control the course and scope of our evolution, though.

Closer than you think.

[Christopher]

It strikes me as mildly amusing that someone who hasn't even HEARD OF any intelligent species besides his own is spending so much time claiming that OF COURSE his own species' body plan is the objective best for intelligent life.

I don't belong to the "humanoid form is the gold standart" crowd. I belong to the "humanoid body is bog-standart/lowest common denominator" crowd. It's only that we have not meet another species what causes us to even call this form "humanoid". Once we meet another species, both sides have to find a better term. We just had no incentive to evolve our langauge along that direction yet.

 

About the whole "we have not excluded other forms of intelligent life are possible" argument:

If we every waited for all the altnernatives to be 100% excluded, we would never have gotten anywhere. 80% certainty is way enough.

"My god has not been disprooven" is a common falacy used by religious people towards atheists. The counter argument is "neither have been those gods from all those other religions."

 

Even after finding our 100ths intelligent, humanoid species people could still bring that "not excluded" argument. If it still holds true after so much counter evidence, it can't have been a good point to begin with.

 

 

Our smartest people are working thier butts & budgets off to find life in our solar system. So far nothing.

All our data indicates that life can only develop and scale up to intelligence* in a earthlike environment. Once we get different data, the theory will be revised.

All theories only last as long as no contradicting data is availible. At wich point the theory is revised and we got a slightly better one. I think our planet and evolution are just that boringly normal that hey might just be the norm.

 

*Bacterial life survives in very odd places. Like near methane volcanoes underwater and even inside our bodies. But the scaling up part is the more important issue.

 

 

 

 

This is incorrect. Are we still reproducing? Yes. Are the offspring genetically identical to the parents? No. Therefore, we're still evolving. It only LOOKS like we've "stopped evolving" because our cultural evolution is far faster than our biological evolution. Yet, new mutations and genetic drift are still occurring.

You forgot the 3rd part to evolution. Selective pressure.

In a environment fully managed by evolution, several people I know - propably me included - would have been selected out decades ago.

 

While people with imparements have greatly diminished chance to reproduce, thier chance is no longer 0.

 

Of course that idea cuts both ways:

For all we know becomming deaf (an impairment) is the next step in evolution (because we no longer need our ears to detect danger, freeing up resources for other stuff).

So maybe we just lessened the impact of physical properties.

 

 

 

Hands do help with gathering.  But we aren't the only ones.  And not just apes & monkeys.  Look out your window.  See the squirrels?

How about raccoon?  List goes on.  We aren't the only ones with manipulative forepaws.  Lots of them are still on all fours - but will also use bipedal orientation when advantageous.  So get over the biped fixation as necessary for hands.  It isn't even true on this planet.

But none of them is using Bipedal full time. Using your hands as feet too limits thier viabiltiy as hands. If not we would have stayed on all fours and only ocassionally use upright walking. Tool users tend to out-climb, out-fly or out-tool thier predators, not outrun them.

 

None of those others designs scale up past squirrel size. Tool-use as much as they do is helping survival. But would a squirrel with twice the brain power (and all the tradeoffs) be a better squirrel? If not evolution will not let it get there.

 

 

 

So how about a life form that evolves on a Titan like body, with 0.14G ??

You really are fixated on life only being possible on an Earth-like world.

Which is rather unlikely.

 

And a bird on a Titan like world wouldn't even need to worry about the limits we have of atmospheric density vs gravity's acceleration.  Birds evolved for our world.  Not another.

And why a 6 legged creature that rose up in a centaur like arrangement would have a problem with pregnancy is beyond me.

Evolution starts way before the bird phase. Lower gravity means lower pressure in the seas. So the microscopic life there will develop differently.

Fishes are practically underwater blimps with thier floatation organ. So on that planet flight could be a lot closer to how fishes swim. No birds at all, but natural blimps.

 

Also since they have no gravity of relevancy, they might never develop bones. No bones results in no manipulatory limbs (see below at answers to Lucius) to use tools with. No intelligent life again.

 

 

Tool use is only one of the benefits of the constellation of traits we call "intelligence" Vitally important, yes, but not the only factor.

 

Language use unlocks the potential benefits of cooperation and communication. A beast can use a distress call and inform the rest of the herd "Predator! Here, right now!" a Human can tell someone "I found the tracks and droppings of a big bear over in the woods towards the setting sun." A beast can communicate the equivalent of "Mommy, daddy, help!" and possibly save itself from being eaten. A Human can say "I tracked that bear to its lair, and there's only one right now, want to come with me and my sisters and set an ambush for it? Enough meat to go around and we can stop worrying about it catching one of our kids if it wanders over our way."

 

And language use doesn't depend on a given body type. There could be aliens with an olfactory language who communicate abstract and complex ideas with pheromones.

You need to be at a certain level of intelligence already before the ability to lie and fake becomes a survival trait. So while it might have been a nessesary step, is it not setteled way after tool use?

 

Also we have not yet decoded animal languages to the level where we can exclude they are doing just that. It's been hard, because thier communication range is largely out of our sensory scope (outside hearing range or using additional senses not as well developed). An additional factor is that each herd has it's own dialect, same way we have on our planet and that the whole thing is less formalized.

And of course there has been a long held asumption that we humans are "smarter" in the language and social departments.

 

 

 

Probably related to language use, we enjoy the benefits of enhanced powers of memory and cognition. The ability to do things like anticipate the future and plan for it confers survival advantage for the individual and the group. A Human can say "I think we should go kill that bear now, before it finds a mate."

 

And again, I don't think that necessarily depends on a given body type.

The ability to detect patterns and react to them. The ability to find the shortest route.

Brains and even cell-walls are unessesary for that:

https://www.ted.com/talks/heather_barnett_what_humans_can_learn_from_semi_intelligent_slime_1

 

We might do it on a larger scale then your average wolf pack or slime mold, but that is about all there is to us.

 

 

 

But aside from the possibility of intelligent, articulate life forms that are not tool users, I don't necessarily agree that only a humanoid form is suited for tool use. The fact that no squid or elephant for example has our level of manual dexterity does not mean that something like a tentacle or trunk could never evolve the equivalent of an opposable thumb, keen tactile sensitivity, and the rest of the complex of traits that enable us to handle objects so precisely.

I see one big issue there: Lack of an Endo-skelleton support for that tentacle/trunk appendage. That is what makes it a non-arm.

As a result pulling, pushing and grabbing force are greatly limited relative to muscle size and appendage design complexity.

 

Even birds use tools with thier (solid) beak. Or is there an example of a boneless form using a tool? If so, could it actually scale up or be made to use more compelx tools?

 

 

 

And a few points about details:

 

- Many creatures other than Humans have mammary glands.

 

- Sleep is far from unique to Humans. Even nematodes sleep.

 

- There is no reason to assume that a hypothetical centaur like species would carry its developing young anywhere but in the same anatomical location that a horse does. In fact, I think it very unlikely it would carry that load in the vertical torso rather than the horizontal torso.

 

- For that matter, there is no reason to assume any hypothetical alien species would bear live young as opposed to some other system of reproduction such as laying eggs.

- many species have them. But only for us are they so pronounced and sexually interesting.

 

- many species sleep. But do they sleep as deeply? Do they even become inactive during sleep? Sharks only sleep with half thier brain at a time. That is how much better at sleeping they are then us. Why are we not sleeping like sharks, since it would be a much better defense against predators?

 

- that still leaves the needless complexity of having to pump all that blood into the upper torso with the brain. Either the brain comes closer to the forelegs (making those the new arms) or the hind leg's come closer to the brain. Or both.

 

- we know of 5 mamal species on this planet that lay eggs. Monotreme is that group called. Must be something bad about it if no other mamal species kept it.

[procyon]

To me, whether sleep is necessary for intelligent life and if it can arise from egg layers is a bit of a non issue.  Neither are part of a definition of intelligence.

 

For an invertebrate using tools, octopi have been recorded using tools to a degree.  Some fish use their mouths to crack clams and such on rocks, and dolphins carry sponges in their mouths to help gather food.  Insects have also been noted to use simple tools in food gathering activities.

Could any of these scale up?  Well, if you look at evolution and take if back far enough - pretty much anything can scale up.  We all came from single cell organisms at one point.

 

I am fairly sure language is going to be a necessity for advancing in 'intelligence'.  That we will ever be able to understand a non-terrestrial intelligent species is doubtful to me.  Regardless what fiction would like to present, we have yet to manage to decode any other species communication on THIS world.  I really doubt we will be able to understand a species that evolved in an entirely different environment in anything but the most primitive levels.

 

As for tool using animals other than us scaling up above squirrel size - I would believe that raccoons have a pretty good shot at it.  They aren't tool makers, but have no problem discerning how many simple tools function.

 

As for human form and 'base level for intelligence' - I can see the logic in your statement.  It's only problem is the same as every other one at this moment.  We have only one example.  When basing any predictions on a sample or data set of 'one' - you pretty much have no predictive power. Until we come up with another example, you could just as easily swap 'only on earth like' to 'only in this solar system' or 'only in the milky way.'  Which I also doubt would be true or accurate.

Although I could be wrong.

[massey]

I'm really not sure what the argument here is.  Evolution develops life into a form that is "good enough".  Does your species reproduce faster than it dies off?  Yes?  Good enough!

 

Any animal that is around today would have evolved to this point through a series of "good enough" steps.  Humans weren't always tool users, didn't always have language, etc.  We had to be good enough at each incremental step.  Exactly when these traits developed is probably something we'll never know.  Whether we would have developed this way in a different environment will also never be known.  All we know is the end result.

 

Once you've got the balance problem solved, walking upright uses less energy than walking on all fours.  Fewer limbs in motion is more energy efficient.  While a tiger is a big muscle car, we are a Geo that gets like 40 miles to the gallon.  We've got a very efficient cooling system as well -- the ability to sweat regulates our body temperature.  We don't have to pant like a dog does to cool ourselves.  Our muscle structure doesn't have the power that, say, an orangutan has, but our muscles don't tire as quickly either.  While we aren't very fast, humans are good distance runners.  There are tribes in Africa today where the hunters run down antelopes.  A human (an in shape one, anyway) can run all day -- antelopes die from heart failure before that happens.  We aren't as strong or as fast, but we can be weak and slow for much longer than other creatures.  Combine those endurance hunting techniques with an omnivorous diet, the ability to climb trees, swim, etc, and the human is a versatile survivalist, even without tools or language.  Other animals are, of course, better at certain things.  But you don't have to be the best, you just have to be "good enough".

 

Intelligence and tool use arguably come from the ability to better regulate our body temps (crucial for brain development), opposable thumbs, our long childhood development which creates a necessary social structure, etc.

 

Adding 5% intelligence to a wolf or a bear would clearly make the animal better than it currently is.  But it isn't necessary.  Humans with 5% better eyesight or 5% faster speed would be better as well, but we were successful anyway without it.

 

Why have humans selected for higher intelligence?  Because once you hit tool use, you've got a tremendous advantage.  The 5% for the wolf or the bear isn't going to make the difference between running in the woods and driving a car.  For humans, every 5% is a better weapon, more food, better clothes, better shelter, etc.  And we can't forget, the ability to kill other humans.  At some point, humans passed the point where their chief enemies were bears and alligators.  They started slaughtering neanderthals and other competing tribes.  At that point, it's direct intelligence vs intelligence combat.

[Netzilla]

 

<snip several salient points that I agree with>

At some point, humans passed the point where their chief enemies were bears and alligators.  They started slaughtering neanderthals and other competing tribes.  At that point, it's direct intelligence vs intelligence combat.

 

Well, that and a combination of out-breeding them and inter-breeding with them.  Humans are a fairly prolific species with a year-round breeding cycle and a fairly long fertile period (even if gestation and childhood are also very long).  As I understand it, we weren't necessarily smarter than other hominins but we were very aggressive and bred very quickly.

[procyon]

  For humans, every 5% is a better weapon, more food, better clothes, better shelter, etc.  And we can't forget, the ability to kill other humans.  At some point, humans passed the point where their chief enemies were bears and alligators.  They started slaughtering neanderthals and other competing tribes.  At that point, it's direct intelligence vs intelligence combat.

I am sure what you are trying to say is true, but the analogy probably isn't accurate.

Discovering a way to adapt unguided bombs into guided munitions is great.  But the folks who did that were not likely 'more intelligent' than Newton.  Or Copernicus.  Or many other individuals from antiquity.

 

The development of language, and ways to record and pass on our discoveries, is a huge advantage.

Lots of primates can use a variety of tools.  But if they have never directly observed another member of their species using it - they are unlikely to 'discover' it.

The same was true for humanity.  We likely 're-invented' the wheel/fire/spear/etc over and over.

Until we found better ways to pass that knowledge on.

 

That would be one of the hallmarks (to me) of intelligence.

[megaplayboy]

language use, tool use, empathy, intuitive reasoning....all of these contributed greatly to humanity's rise.

[Old Man]

language use, tool use, empathy, intuitive reasoning....all of these contributed greatly to humanity's rise.

 

 

[Lucius]

- we know of 5 mamal species on this planet that lay eggs. Monotreme is that group called. Must be something bad about it if no other mamal species kept it.

Absolutely true. Absolutely irrelevant. I don't think you're making even the tiniest effort to identify and question your own assumptions.

 

Lucius Alexander

 

The palindromedary says of course there's something wrong with egg laying - that's why birds, reptiles, amphibians, and fish don't do it anymore.

[Lucius]

 

Because Christopher may appreciate it, and to acknowledge the truly profound importance of tool use:

 

 

 

Lucius Alexander

 

On still another hand, I have a palindromedary