Evolution Q&A: Why did only humans become intelligent?

Ahmad Fares has asked me a second question about evolution. Because he was very polite and sincere in our last discussion, I will try once again to give a thoughtful and complete answer this time as well.

Ahmad's tweet.

Just as with the last time we talked, Ahmad, I’d like to start by talking a little bit about the context of your question.

You have said openly and plainly that you do not believe in the  theory of evolution, and that the purpose of your questions is to cast doubt on the theory of evolution. In this particular case, however, I don’t quite see how this question fits into the “grand scheme” of that goal.

Are you trying to imply that if the theory of evolution were true, then it “should” have produced more than one species with our level of intelligence? I’m not sure exactly why you would think that.

For one thing, intelligence is not an all-or-nothing phenomenon. Humans are smarter than chimps, and chimps are smarter than dogs, and dogs are smarter than mice, and mice are smarter than starfish. Humans happen to be an extreme on the scale of intelligence, when compared to other species.

But we are not the only extreme species. Whales are extreme when it comes to size; hummingbirds are extreme when it comes to the speed with which they flap their wings; bacteria are extreme when it comes to being very small; giraffes are extreme when it comes to having long necks; and barnacles are extreme when it comes to the size of their penis (relative to their body size).

In a world where there is such variation in sizes and shapes and types of creatures, it is only natural that there will be different creatures that are at the extremes for different traits. For humans, it happens to be intelligence.

So one way to look at your question is to point out that humans aren’t the only things to become intelligent. We are simply the species that happens to be the most intelligent. We aren’t especially big, and we aren’t especially fast. Intelligence just happens to be “our thing”.

For another thing, the fact that there are species that have unique and distinct traits, different from all of the others, is not at all contradictory to the theory of evolution. There are many random processes, not guided by design or intelligence, that give rise to unique and unusual situations.

You dump a bowl of oranges on to a table. They scatter, and one rolls on to the floor. Do you ask: “Why did only that one orange fall onto the floor? Does that mean that one orange was given a special reason to fall on the floor?” Or did it just happen?

You pour water over your plants. Some falls on the soil, some falls on the leaves, and one drop falls into a flower petal. Can I therefore conclude that you must have intended that one specific drop to fall on the flower petal? That some special force directed that one drop to fall in a place different from the others? Or did it just happen?

Sometimes, when nature is going about its normal, chaotic, random activity, some things happen differently than other things. That’s just part of how nature works.

But maybe  you were implying something else.  Maybe you are suggesting that intelligence seems like a very useful thing, and that it seems intuitive that many things would have also evolved this useful characteristic. For example: wings are useful! And many things evolved wings: insect, birds, some weird kinds of lizards, and so on. Why isn’t it also like that for intelligence?

To answer this, I have to go back to one of the basic principles that I described in my earlier response to you: evolution actually does not have a bias toward evolving things that are particularly useful in a general sense. That is a misconception about how evolution works. Evolution is based on the idea that differences happen randomly, and when a random difference is especially harmful, it is weeded out. This leaves the next generation that is slightly different in its overall average composition than the earlier generation.

To help to illustrate this better, let’s talk about giraffes for a moment.

Natural SelectionGiraffes have a really long neck. I mean: really, really long. Why are they the only things that have necks that are that long?

There was never any directive overall force that decided, “Hey, look! Long necks would be helpful now! Let’s make that happen!” Giraffes didn’t get longer necks because some giraffe said, “Wow, I wish I had a longer neck! That would help!”

Instead, there were giraffes with many different lengths of neck: some short, some tall. When food was scarce, only the ones with the longer necks could reach the highest branches to get more food. Therefore, they survived. The shorter ones did not get as much food, so they died.  As a result, in the next generation, the average neck length of the entire population was slightly longer. This would then be repeated over and over again.

Of course, it doesn’t get repeated indefinitely. Once all of the giraffes in your population, even the ones with the shorter necks, are well-fed and able to get food, there is no longer any pressure for change. As a result, if food is plentiful and can easily be accessed, neck sizes stay the same.

It’s also important to notice that not every animal’s neck size increased. Monkeys didn’t grow long necks, because they could solve the problem a different way: they climb. There was therefore no reason why short-necked monkeys would die off more than long-necked monkeys.  There is no disadvantage to having a short neck, if you are a monkey.

How does this relate to intelligence?

Intelligence evolved in the same way. Gradually, over time, there were certain characteristics that actually were relevant to survival. The environment was set up so that our ancestors who could use signs and symbols, for example, were able to survive and reproduce better than those who couldn’t. So as a result, those traits spread throughout the population.

But different animals live in different environments, and in different niches. A lion is the king of its domain: at the top of the food chain. If one lion has a better memory than another, or can think faster than another, that doesn’t necessarily mean it will be able to survive better or get more food. It is like the short-necked giraffe in a land where food is plentiful and low to the ground: there is no selection that “weeds out” low extremes of the trait. So if there is nothing that weeds out lions with mediocre memories, then there is no reason for the average power of a lion’s memory to grow. If there is nothing that weeds out lions who can’t solve puzzles, then there is no reason for the ability of lions to solve puzzles to improve.

Intelligence will only evolve when there is a specific problem that it solves. It will only evolve when something in the environment is killing off the animals that are on the “low end” of the population.

Now the final prize-winning question, of course, is what was so special about the environment of early humans that made intelligence an adaptive trait?

Here, I will admit something to you: We’re not certain. There are lots of theories out there. In fact, there are entire books dedicated to the topic. But nobody knows for sure, yet. This is a detail of evolutionary theory that is still being worked out.

That’s ok! These things take time.

But the take-home message that I would like to leave you with is this: there is nothing inconsistent or magical with the idea that humans are the only species that evolved intelligence.  Just like there is nothing inconsistent or magical about the fact that giraffes evolved long necks but monkeys didn’t. This kind of variation and individuality is exactly what one would expect from the principles of the theory of evolution.


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  1. Jack Giorgio says:

    but why can only humans make nuclear weapons (and coordinate an effort to use them) that can devestate the entire planet? If evolution was a competition i’d say humans took a firm lead. You’re all dancing around a clear truth that something really profound lies at the center of human intelligence. And i firmly believe in evolution.

    • Greg Stevens says:

      Hi Jack! Thanks for your comment. I think the phenomenon of intelligence is incredibly profound. And interesting, and fantastic, and qualitatively different from any other biologically-produced process that we have ever come across!

      But help me understand how that relates to what I’m saying about evolution in this post. What inference, exactly, do you get from “intelligence is special”, in relation to evolution?

  2. Greg Grimer says:

    Instead, there were giraffes with many different lengths of neck: some short, some tall. When food was scarce, only the ones with the longer necks could reach the highest branches to get more food. Therefore, they survived. The shorter ones did not get as much food, so they died. As a result, in the next generation, the average neck length of the entire population was slightly longer. This would then be repeated over and over again.

    Question. Why would we not find giraffe like creatures, grazers, with long necks and legs, on every continent in that case? We find grazers everywhere, and short neck grazers of all types would have eaten the food from the lower branches. If a long neck was such an evolutionary advantage in Africa that the giraffe evolved it, and being able to reach food that other grazers cannot is an enormous survival advantage, then why not Australia and the Americas, which would have suffered from periods of drought also?

  3. Nicole says:


    I am enjoying getting caught in the rabbit hole of your blogs. Thank you for your insight and thoughtful answers.

    Something to ponder:

    Doesn’t ‘intelligence’ in itself have a human skew? Dolphins are highly intelligent but because they can’t speak, build computers or live in air conditioned homes most would consider them not as intelligent as humans. But dolphins and whales have been shown to have higher cognitive ability than humans.

    I think the only ‘greatest ability’ humans can claim is egotistical thinking because we are definitely the most ego based animals on the planet. And that FYI is based on observation not science.

  4. Norm says:

    However, the question that begs answering is the why only humans developed this level of intelligence over billions of species and others did not come even remotely close.

    After all, there are creatures that approach the whales in size, humming bird in speed, amoeba in smallness. Sauropods had even longer necks than present day giraffes as a proportion of their body size.

    Why did only humans reach this level of intelligence (and related capabilities like speech, dexterity, vocalization) out of billions of species and none come even close to it. To write it off to chance as you do, would put the probability of that happening at one in billions – almost making it improbable. The converse – that none of the billions of species that have inhabited earth found the need to develop intelligence as their ‘thing’ as you call it other than man also sounds hollow.

    Thoughts ?

    • Greg Stevens says:

      Looking at archeological findings, Homo Sapiens (our species) aren’t the only ones to have developed intelligence… we’re just the only ones that survived. It appears as though at least three similar species evolved tool-making, some version of clothing manufacture, and art / drawing all around the same time. There is some disagreement among anthropologists as to whether Homo Sapiens simply wiped out the other species, or we interbred with them, or we just were so much better at hunting and agriculture that we starved the other groups out. But regardless of the exact mechanism, the fact of direct competition among different varieties of the genus Homo that lead to us being the ones that survived.

  5. kent norton says:

    What about sponges? They have no brain ,neurons or nervous system, All they do is filter water for micro nutrients, they don’t even have a mouth or digestive system, to speak of. Are they intelligent? They just stay anchored to a rock and feed all day till some river pulls them into a net, cleans them and sells them in Greece or Tarpon springs, fl. Some life.

    • Greg Stevens says:

      Thanks for your comment, Kent! I’ll admit I’m a little bit confused about how your question relates to the article. I actually say near the very beginning,

      “For one thing, intelligence is not an all-or-nothing phenomenon. Humans are smarter than chimps, and chimps are smarter than dogs, and dogs are smarter than mice, and mice are smarter than starfish. Humans happen to be an extreme on the scale of intelligence, when compared to other species.”

      I think this answers your question: intelligence isn’t a yes-or-no question. Sponges are less intelligent than some things, they may be more intelligent than others. Does that answer your question?

      • Syahrul arfany says:

        An example of darwin theory about girrafe is a total idiocy. First of all there has been no proof that there has been girrafe with short neck ever found or any fossil found as proof. Secondly why giraffe has to have a shorter neck while it has a very long leg. So the reason giraffe has longer neck more to the fact that it has long legs. Like horses zebra and the rest for legged animals so it could reach gound.

        Theory of evolution biggest flaw is in its own basic arguments. That mutation and natural selection is driven by the nature that has the tendency to maintain balance. But before the earth is occufied with living organism the question is what drives living organism to exist. Should the nature tend to maintain balance living organism would have no place in the nature since the nature of living organism is corruption, causing corrotion and create paradox to the nature. So what drives to the existance of living organism in the first place ?.

        Evolution spare no room for paradox and freewill so there is no reason for intellience in the nature. Nature would eliminate inteligence in its first appearence. Like living organism would be destroyed by nature in its early stage should you believe nature has force to mutation and natural selection nature would not allow it from the very beginning. theoey of evolution contradict its own basic arguments.

        • Greg Stevens says:

          Thank you for your comment, Syahrul!

          I have a couple of questions for you, though.

          First, this section confused me: “Should the nature tend to maintain balance living organism would have no place in the nature since the nature of living organism is corruption, causing corrotion and create paradox to the nature. So what drives to the existance of living organism in the first place?”

          The purpose of evolution isn’t to explain how life came to exist. That is a separate scientific question. There are many theories about possible answers. However, the theory of evolution is completely unrelated to this topic. Evolution is an explanation of how living things change over time, not how living things happened in the first place.

          Moreover, if you happen to believe in a Creator God of some kind, the theory of evolution is not even in contradiction to that assumption. There is no contradiction in believing that life was FIRST created by a Creator God, and then also evolved over time. The question of creation is separate from the question of whether or not evolution happens.

          Second, you said: “Evolution spare no room for paradox and freewill so there is no reason for intellience in the nature.”

          This also seems like you are assuming many beliefs are linked to evolution, when in fact they are not. The theory of evolution isn’t IDENTICAL TO the theory of simple philosophical materialism. It is entirely possible to believe in free will, or even spirit, and also believe that living things evolve over time.

          It is possible that you are very used to “two sides”, where one side believes in evolution AND ALSO denies free will or God, while the other side believes in God AND ALSO denies evolution. But these are not actually linked. It is logically coherent and possible to believe that there are organisms that were created by a God and that have free will, that ALSO change from one generation to the next according to the mechanism described by evolution.

          • Des says:

            but you didn’t address the issue of long legs for the giraffes. Why did they not simply get long necks, or simply long legs, but they got both long necks and long necks. And how do you know that is the result of evolution? Do you have proof that they originally had short legs and necks, and then evolved to have long legs and necks?

          • Greg Stevens says:

            There are plenty of fossils of giraffe ancestors showing how their neck (and leg) length changed over time.

            From: https://www.sciencenews.org/blog/wild-things/how-giraffe-got-its-long-neck

            “Giraffes, it turns out, are not the first species in their lineage to have a long neck — they just have the longest one. The species started off with a shorter neck, 7.5 million years ago, when it first appeared on the scene, after which the neck became even longer. But the lengthening began even earlier in the giraffe’s lineage, the fossil analysis revealed. The extinct Giraffa sivalensis shares some of the elongation features found in the modern giraffe. But even it wasn’t the beginning of the journey. Two other extinct creatures from the giraffe family Giraffidae, Samotherian and Palaeotragus, also show some of these features, as does the primitive giraffid Canthumeryx”

            Giraffe family tree

  6. Epiphyte says:

    You really did the theory of evolution justice! I, on the other hand, really suck at doing theories justice. Watch…

    So… humans are exceptionally intelligent. What is exceptional intelligence good for? It’s good for solving exceptionally hard problems. But why did early humans, out of all the animals, need to solve exceptionally hard problems? It’s because out of all the animals, early humans had the greatest ability to (simultaneously) allocate the widest variety of resources. This exceptional ability was the result of having hands, arms and… walking upright.

    With quadrupeds… all four limbs are primarily dedicated to allocating a single resource… the animal itself. But this specialization is a continuum that ranges from horses to raccoons to chimps. Horses obviously have four legs. All their limbs are quite specialized to allocating only the horse itself. None of the horse’s limbs are remotely capable of allocating other resources. What about raccoons? Do they have four legs? Well, their front limbs are reasonably capable of allocating other resources. Chimps definitely do not have four legs. They have two legs and feet and two arms and hands. They are quite capable of allocating other resources with their arms and hands.

    As front limbs become less dedicated to only allocating the animal itself and more generalized to allocating other resources… there’s an increase in the total variety of resources that can be (simultaneously) allocated. This creates a more difficult/complex allocation problem…. which requires more brain power/storage to optimally solve. Well… a distinct advantage is given to exceptionally intelligent individuals.

    Since you’re fond of using lions as an example… let’s compare them to zebras. It would seem that the front limbs of the lion aren’t as specialized to self-allocation as the front limbs of the zebra are. Lions certainly use their front limbs to allocate themselves… but they also use their front limbs to allocate their prey. But perhaps the biggest difference is that the mouths of lions are quite capable of carrying/allocating resources (food, cubs, other?). Do zebras use their mouths to carry anything? Not so much? Therefore, lions are faced with more complex (allocation) problems than zebras…. and we should suspect that lions are more intelligent as a result.

    So…. for lack of a better word… more “resourceful” body types put greater selection pressure on intelligence. Humans are the most intelligent animals because our body types are the most “resourceful”.

    • Greg Stevens says:

      I really like this theory! It’s very thoughtful and interesting.

      One question I have: how can this approach explain why octopods don’t have as advanced symbol manipulation and culture as humans. Surely more of their bodies is able to allocate resources more flexibly and in a greater number of ways, yes?

      • Epiphyte says:

        I’m hardly an octopod expert. When I googled “octopus carrying” I found this picture of a mom with 8 arms. According to the allocation theory she must be a lot more intelligent than us! Also found this cartoon of an octopus carrying different things. There seems to be a bit of disparity between fiction and reality though. I only managed to find this video of an octopus carrying a coconut. I added it to my playlist of different animals carrying things.

        According to Wikipedia… octopuses are “highly” intelligent. But why aren’t they even more intelligent? One explanation might be that they die after reproduction. No matter how exceptionally intelligent an individual is… it’s not going to exert significantly more influence on the gene pool than any other individuals.

        With early humans… exceptionally intelligent individuals were more likely to optimally solve complex carrying problems… which meant that they were more likely to live to produce many more offspring than other individuals. This shifted the gene pool in a more intelligent direction. With modern humans though it’s a different story. Survival/reproduction is far less dependent on successfully solving complex carrying problems. Therefore, exceptionally intelligent individuals are not going to shift the gene pool in a more intelligent direction.

        We’ve reached peak intelligence! Of course this might change if we start seriously colonizing space.

        With octopuses there’s also the issue that they don’t seem to have 100% control over their limbs! We have far less “carrying parts”… but we do have 100% control over them.

        Perhaps another issue is that carrying things in water is easier than carrying things on land. This means that there’s less of an energy cost when the wrong things are carried in water. Of course in both land and water the opportunity cost is equally high when the wrong things are carried.

        Also, octopuses don’t have a very distinct division of labor between carrying limbs and locomotion limbs. As the saying goes, a jack of all trades is a master of none. As humans we have legs for walking and arms/hands for carrying. So we maximize two factors… distance and difference. We can carry the widest variety of different resources over the greatest distances. I’d bet that any aliens that visited our planet would have, or used to have, a similarly distinct division of limb labor.

      • Timothy Anderson says:

        Lol…. POV’s that support one usually seem insightful and interesting. Many points you make during your justifications are unsupported hypothesis to fend off the question. The same type of argument you’d make against any other theory. Open you mind to the possibility that we as a species don’t have the answers to life’s biggest questions. One should stand on their beliefs, but be respectful and open to the very real possibility that their belief may be wrong…including myself.

    • BLawson says:

      Except by your logic all primates should have ended up in the same place.

      • Greg Stevens says:

        Well, no, that argument doesn’t make sense.

        It makes the same amount of sense as saying: “If humans came from Adam and Eve, then all human beings should be exactly the same!”

        Neither argument makes sense: all creatures have small random variations from one generation to the next; they spread out and live in different environments, which cause them to respond differently and behave differently; small differences end up being more or less important, depending on where groups live; and so populations drift apart.

        Even if you don’t believe that one species evolves “into another”, it’s a mis-statement of the fundamental idea of the theory of evolution to think that if one group of species X evolves trait Y then ALL of them must… that’s not how the process works.

      • Epiphyte says:

        “Except by your logic all primates should have ended up in the same place.”

        Bats are mammals that are exceptionally good at flying. Humans are mammals that are exceptionally good at walking upright. Walking upright makes us exceptionally good at allocating resources. Being exceptionally good at allocating resources puts an exceptional amount of selection pressure on intelligence. Therefore, humans are exceptionally intelligent.

        If all the humans left this planet and colonized mars… then it’s a given that, in the absence of any sort of massive natural disaster, some other primate would evolve to become exceptionally good at walking upright. As a result, they would also become exceptionally intelligent.

        On Netflix I was watching some nature show and they were showing those wonderfully bizarre creatures that live near the underwater thermal vents. The narrator said that at anytime the vents can simply cease to function. When that happens it spells disaster for the creatures that depend on its existence.

        This means that life is synonymous with colonization. Flying sure facilitates colonization. So does walking upright. But walking upright and having arms and hands also facilitates the allocation of resources… which facilitates the development of the intelligence needed to colonize other planets. Nature created us humans so that she wouldn’t have all her eggs in the same basket (Earth).

        Unfortunately, humans don’t quite grasp that progress is a function of difference. So we allow a small group of government planners to spend all our taxes for us. This results in too many eggs in too few baskets… which hinders progress… which greatly increases the time it will take before we can successfully colonize other planets. And the longer it takes to colonize other planets… the greater the chances that we’ll be wiped out by some massive disaster.

        There you go… evolution and economics in a nutshell.

  7. Mojtaba says:

    Thank you Greg, it was really convincing indeed. I do believe in evolution, I don’t understand why people try to defy it.
    Well, I want to talk about the part you gave Ahmad the lion intelligence example. You are right. The lion simply does not need to be smart if it wants to survive. And the smarter brains won’t help lions to better survive than the rest.
    But once alone, I was wondering why humans would have such an intricate eye? I mean we also could have survived with more simple eye. You might say that the eyes are the heritage from our ancestors. But still, they could also have survived with those simple eyes. Those critters needed something to distinguish the danger, without needing to distinguish as sharp stuff as a left apart star in the sky or the very wide domain of wavelength of light –color. I think over this case, I mean eyesight, we also hit another extreme, don’t we? Or at least we are very good at it in comparison with millions of species out there.
    How have we got this? Weren’t we like lions with lower memories if we had poorer eyesight visions, in terms of survival? What do you think?

  8. Justin says:

    Ahhh but my good sir intelligence is universally dominant. When the planet ends someday as all do, only the most intelligent will survive after that (assuming we still exist). At this point we will have dominated every other organism and our intelligence will keep us living long after all of our earthly cousins (assuming we all came from one organism) have been blinked out of existence. If we are able to do that our intelligence will have won over all other survival traits. Intelligence may not have been the most important trait in the beginning, but in the end it will be (assuming we don’t destroy each other with our technology advancements before then).

    • Greg Stevens says:

      “When the planet ends someday as all do, only the most intelligent will survive after that ….”

      I’m going to stop you right there.

      So you are thinking there will be no plants on this Future Earth? No insects? No algae to soak up the sun?

      That is not how ecology works, and that is not even remotely what evolution predicts. As I said in the article (and I hope you will believe me instead of simply ignoring it): evolution does not select based on some kind of universally “useful” scale. It only removes things that are harmful for a specific organism, in a specific environment. That is why we have so much biodiversity… and it is an absolutely crucial element of evolutionary theory, if you truly want to understand it.

      • Justin says:

        You are correct I should have been more specific. Our sun will not always be here. What will happen after that? So far all of our scientific research suggests that there must be a sun for organic life to exist. I’m not saying that that’s true but even tartigrades need water to survive. Can life exist without a water cycle, as far as we know water cycles cannot exist without a sun. The earth will be consumed by our sun as it expands through it last breath before burning out and leaving our home in icy darkness. The only thing that would ever save a species during that event would be their intelligence and their ability to survive without a planet. When that happens and if we develop the technology we will still survive after all other life has died. I suppose our intelligence wouldn’t even be dominant at that point without competition but it would be the very essence of ultimate survival, even after our wonderful life making sun has passed.

        • Greg Stevens says:

          Thanks for clarifying what you meant. It was a little confusing, because what you are describing has nothing at all to do with the process of biological evolution, nor is it at all relevant to the evolution of “intelligence”: how or why it may have happened, or why other animals have not developed certain capabilities that we have. So it was, as the saying goes, kind of from out in left field.

          But, having said that, you have a very creative way of looking at things. When looking at the broad scope of time, could it be that the development of “intelligence” is the only thing that will get a world ecosystem past the bottleneck of the collapse of its own solar system? Perhaps. Perhaps not. It seems reasonable to think that very unintelligent seed pods could be spewed into space, and survive a very long time in an extra-solar environment. So I’m still not sure that “intelligence” counts as the ONLY thing that will get life past that (very serious) future bottleneck in development. 🙂

  9. Richard says:

    Almost every creature here carry many of the same abilities and capabilities. Very few types of living beings have capabilities soley unique to that being. I understand there are beings that posses soley unique traits/capabilities . But this most definitely the exception and not the rule.

    Why is it that only humans have a written language? How come birds don’t have air conditioning in their nests?

    A lot are there so many diverse species. If the survival of the fittest is true there would be no reason to have more animals than different than environments. Starting out with such basic life forms (not my beliefs, I believe we were created from the beginning) there would be far less diversity. Swamps are swamps, when basic life forms made thier way to earth, simple life forms in swamps, for example , most swamps located in the same region are so similar in thier environment that every living creature would have all followed the same path. there would be no reason for the same conditions causing things in enviornment affecting it’s survival and survival of the fittest. If these things experienced all the same stressors they would have all turned into the same thing with very little differences between them.

    I understand there are arguments that one could use, but all the reasons i could think of would fly in the face of a lot of evolutionary theory.

    For current theory to be held true the beginning amount of living orgenviornments the big bang” would have needed to have either a massive amount of significantly different enviornments or a massive number of creatures that were different from the beginning and thus having different needs.

    • Greg Stevens says:

      Hi, Richard! Thanks for your comment. Since you’ve said outright that you don’t believe in evolution, I’ll start by saying that I will not try to change your mind or “force” you to believe anything. However, I do want to correct some of the mistakes that you have made in your comment, so that your future questions and criticisms can be more productive.

      1) “I understand there are beings that posses soley unique traits/capabilities . But this most definitely the exception and not the rule. Why is it that only humans have a written language?…”

      This argument seems muddled. You say that you UNDERSTAND that some species have unique traits, and that it is unusual. That’s fine. But then in your next sentence you seem to completely ignore what you just wrote, insisting that there be some special cause for unique traits that humans have. You may as well ask, “Why is it that only leopards have leopard spots?” or “Why is it that only giraffes have really long giraffe necks?” (This is a question I actually try to answer in the article, by the way, so you may want to go back and re-read it.)

      2) “most swamps located in the same region are so similar in thier environment that every living creature would have all followed the same path”

      This is a simple misunderstanding of how physical systems work. When you pour water onto the top of a hill of dirt, does all of the water follow the same path down to the bottom? No, the water splays out in all different directions, forming many little rivers and channels that split and merge on their way down. When you toss a bag of oranges onto a table, do they all roll in the same direction? No, they all roll in different directions and they bounce off of each other and can end up in very different locations.

      Identical twins can have different weights, and shapes, and heights, depending on the environmental conditions they are exposed to and the choices they make. I myself know a pair of identical twin brothers, one of whom had a very muscular in-shape body and the other of whom is overweight. They simply encounter different situations in life and make different choices, so they are different, despite having identical genetics.

      Such is how it is with all biological systems. Small differences in genetics and phenotype get amplified, generation over generation, to become large differences. They interact with their environment, which can push some organism populations on one direction or can push other organism populations in another. There is no such thing as two organisms that experience EXACTLY the same environment.

      3) “For current theory to be held true the beginning amount of living orgenviornments the big bang would have needed to…”

      I’m not really sure why you are invoking the idea of the “big bang” here, but I’d encourage you to read up a little more on some of these theories to make sure you understand just the basic. The term “the big bang” refers to a theory in physics about the early history of matter in the universe. It has nothing to do with biology, or life, or species diversity. When you start talking about the “big bang” in a conversation about biological evolution, it signals to people that you don’t fully understand what the “big bang” or evolutionary theory actually are.

  10. Bryant says:

    I want to start by saying I am trying to understand with an open mind about evolution but I have a few questions. You stated a giraffe grew a longer neck because his food source dictated it. You also imply they are the only animals with necks to this scale however dinosaurs had long necks before giraffes. Furthermore there are numerous animals that have adapted long necks as well. With the thought to humans being of higher intellect and why, I do not know any other animal that has anywhere close to similar qualities. I am not saying evolution does not occur. That would be an ignorant statement. We can all see evolution in humans just in the past 200 years as far as humans average size and health. A lot of that is due to technology but is the advancement of technology not evolution in it self. Furthermore do you know any other species that has evolved so much and is still evolving at an ever growing pace. Why are we so different in the pace and longevity of evolution.

  11. Caliel says:

    How do you evolve self awareness? And where did the first life come from to start evolution…. you can explain that from The first cell splitting off after several gens of reproducing figured ed out colonization was superior in there environment and then came an organism and in this means you can explain how appendage came and tissues in the brain that gives one intelligence…. but it still doesn’t answer where did the very first life come from….. and I know we are still not sure what causes self-awareness weather it’s something pysical or not….. but I would still like to here your Theory of how it’s possible for it to generate

    • Greg Stevens says:

      Thanks for the comment, Caliel!

      You are correct that evolution doesn’t explain the origins of life; and it was never meant to. This is one of the most frustrating “non-arguments” of evolution that I see, because the theory of evolution was never intended to be an explanation of how life began. Criticizing evolution as “not able to explain the origins of life” is like criticizing a theory of gravity for not explaining why the sun is yellow…. it’s just not part of what it does.

      But if you’re just curious about my own opinion, I’ll say this: I don’t really know how life began. Or consciousness, for that matter.

      I have more of an opinion about consciousness than about life, I suppose. Consciousness in the sense of “self-awareness” is a pretty complex thing that arises from us not only having a mental “picture” of the world around us, but also of our own position in it. I think that as neural systems got more and more complex, animals began to be able to construct more and more elaborate mental models: mental stimulations not only of what the world might be like, but what might happen in the future if we do different things, what the world would be like if we had acted differently, all kinds of fantasy / counterfactual scenarios. These require putting together all the individual senses and beliefs and reflexes that we have into a kind of coherent “whole” representation that includes our own position in the universe. I think it’s that level of symbolic complexity that leads to the perception of “self”.

      I realize that’s a big vague… but it’s the best I can do at the moment, I’m afraid. 🙂

  12. bleh says:

    Why such a huge leap in advantage over all other animals? If humans stayed the same as gorillas, humans would have still survived. And there would be somewhat balance in the ecosystem. The crazy circle of life. But humans had evolved not just to survive but to be dominant. Not just over one rival species. But to all species on the planet. Doesnt seem like evolution to me.

    • Greg Stevens says:

      I don’t grant the premise that humans are dominant “to all species on the planet”. I’m not even sure how you’d measure such a claim. In what way are we dominant over amoeba? They outnumber us millions to one, they reproduce faster, they are able to survive in more extreme conditions.

      I think you’d have to come up with a very concrete and specific way of talking about how one species “dominates” another before you could really make a claim like that.

      • Ryan Kline says:

        Well one could make the point that we are the most dominant in the control we have over our environment. But again, evolution does not have a plan, so how evolution would come into what we have achieved with those few mutations is not even on topic.

  13. Quin says:

    I think the twitter users point is that if evolution were strictly true, and even if you consider that not all animals require intelligence to thrive, there should be some moderation along the spectrum of intelligence amongst species of mammals (let alone all animals).

    To this point, it does not exist. There exists a huge gap between the lowest denominator of human intelligence and the highest denominator of any other species. What forcing function forced the application of intelligence on humans and not other primates?

    That’s a legitimate issue that at the moment can not be answered.

    The examples of other extremes are really non-sequiturs. You can’t compare the usefulness of wings to the usefulness of intelligence, because intelligence will always be superior in survival.

    • Greg Stevens says:

      Thanks for your comment, Quin.

      I’m going to focus on the following comment, because although I’ve responded to it many times before it is a misconception that seem to come up again and again:

      “because intelligence will always be superior in survival.”

      This is just not the case. It’s based on a misconception about how evolution works. There is literally NOTHING that is “universally” superior in survival, because the evolutionary notion of “fitness” is always only defined with respect to a specific organism in a specific environment. A characteristic that might help one organism in an environment might be indifferent for another.

      In this article, I tried using the example of long necks on giraffes. Having a long neck is a benefit for survival when there is little low-hanging fruit and much competition. If the fruit on the trees were plentiful and low-hanging, there would be no evolutionary benefit to having long necks. The thing that caused long necks in giraffes to be beneficial was scarcity.

      But there is another factor, as well, that I mentioned in the article. Long necks weren’t a benefit for monkeys, because they climb. If you climb, you don’t need a long neck to reach high fruit. So a trait that is beneficial to one specials that has one set of circumstances it not beneficial to another.

      This same thing holds for “intelligence”. The example that I’ve used before, in comments here and in my writing in other places, is lions. Imagine a family of lions living in a flush, fertile plain with plenty of animal life around. They are at the top of the food chain. They can get all the food they want simply by being fast and strong. Suppose now you have a lion who has a better memory, or better planning ability. She might be able to kill a few more antelope, sure. Through cleverness, she might be able to be a little fatter and a little more relaxed than the lions who have to work a little harder (to make up for not being as clever). But since the environment is rich and they have no predators, both the clever lion and the non-clever lions reproduce at equal rates. There is no evolutionary benefit for intelligence in that environment.

      Intelligence has been just ONE of many possible solutions to a particular scarcity problem during a particular period in human history. There is absolutely no reason to assume that that same solution would have been selected for by animals in other niches. Evolution simply doesn’t work by “looking for” traits that are “good” — it works by “weeding out” traits that are harmful.

      Anyway, I hope this explanation helps to make that a little more clear. If you come away from this with nothing else, I hope you can come away from this understanding that “intelligence” — as wonderful and rare and beautiful and mysterious as it is — is not something that “should be useful” for all species universally.

      • G Nieva says:

        You said:

        “Evolution simply doesn’t work by “looking for” traits that are “good” — it works by “weeding out” traits that are harmful.”

        It sounds like good traits are no important. Are you sure we can rule out beneficial traits on evolution?

        Correct me if I am wrong but I thing you missed two important facts:

        The first one is balance, intelligence as a trait could be very desirable but it is also very resource intensive.

        The second one I am not so sure. Since evolution works using existing organisms only certain changes are viable. While mutations are random natural selection is not. Maybe the mutation path towards intelligence only made sense on our species. The change on the Skull/Neck angle (some experts think very important to increasing brain size) could allow room for mutations without being particularly harmful.

        • Greg Stevens says:

          Ah… you are correct, those are BOTH very good points that I failed to mention.

          “intelligence” is very metabolically intensive, so although it is a good solution for certain types of problems it’s not necessarily a solution that has no costs… those costs could easily prevent the development of intelligence in the early stages.

          And as you said, since evolution works incrementally it isn’t just a matter of getting to “Goals state X”… there has to be an actual evolutionary pathway of incremental transformations, each of which is viable on its own at least for a period of time, that can allow the organism’s genome to drift from where it is currently to X.

          Thanks very much for bringing those up…. very important points!

          • G Nieva says:

            I forgot to mention another quite rare and important trait we have: Hands. Intelligence seems quite the trump card… unless you are a horse.

          • Greg Stevens says:

            I’m not sure I understand…. what do you think the relationship is between intelligence and hand development? I’ve read some people theorizing that the development of intelligence required fine motor skill to really be effective, so that hand development was an important precursor to the development of intelligence… but I’m not sure how this makes intelligence a “trump card”?

          • G Nieva says:

            You need a way to manipulate your world, higher intelligence needs a way to be applied.

            Hands didn’t have a locomotion use and therefore were not specialized for that which it is also a disadvantage when you have that smilodon behind you. But hands allows the use and manufacture of tools, obviously we depend on our tools, a path toward higher intelligence could be explained that way.

            Another point apart: We weren’t the only species to develop intelligence. Homo Erectus shared the world with us and by then we were two different species. The best explanation there is actually only one intelligent species is because we out competed them. We were fighting for the same niche and, being intelligent, the course of action was clear.

            High intelligence is a trump card. Species tend to become more specialized on their niches until reaching a dead end. Intelligence is the only specialization who allows flexibility.

          • Greg Stevens says:

            “High intelligence is a trump card. Species tend to become more specialized on their niches until reaching a dead end. Intelligence is the only specialization who allows flexibility.”

            I’m still not sure I understand what you mean by “trump card”… or by what you mean when you say other species reach a “dead end”. Evolution of all species results in changes that are determined by changes and pressures in their environment. Once a species is well-adapted to its environment, there is no pressure for it to change… so it does not change. This is no less or more true of humans relative to other species. Maybe you can explain more what you mean?

            All of your other points are very good, and I love your comments! I just get confused about calling intelligence a “trump card”. I doesn’t really allow us to “overcome” evolution, after all…. it’s really just another way of adapting.

  14. Anonymous says:

    Flowers do not have pedals.

  15. Cecilia says:

    Wouldn’t intelligence help all life survive better? I would answer yes. But let’s say intelligence has a minimal requirement that not all species can meet – a certain type of brain – a degree of complexity of the brain. In the evolution of a species – where ‘hardware’ changes improved its survivability more – a species may not need a bigger brain – and so it never got to the minimal requirement for intelligence.

    But then, why don’t all monkeys have some degree of our intelligence? I would think they would be close to meeting the minimal ‘hardware’ requirement – specially considering we share most of the DNA. Shouldn’t we have seen some range of intelligence among the primate species of the world?

    • Greg Stevens says:

      “Wouldn’t intelligence help all life survive better?”

      Well, it depends on what you mean by “better”, for one thing. You see, evolution doesn’t REALLY work by selecting things that work better in some kind of abstract sense: they only really help a population that leads to a real, practical improvement of reproduction or survival.

      So the example I like to use is memory span (which is one aspect of intelligence) in lions. Lions are fast and strong — they are at the top of the food chain in their domain! They hunt and kill, and as long as the environment is favorable and there are plenty of prey around, they are fat and happy and live nice fulfilled lives just by being fast and strong.

      And in that environment, a lion with a good memory wouldn’t have an evolutionary advantage over one with a bad memory. Sure, he might be able to remember where to find the best prey, and therefore might be a LITTLE fatter and a little happier than a lion with a bad memory. But both the lion with the good memory and the lion with the bad memory will survive, and both will reproduce. There is no evolutionary pressure to drive the population overall to have a better memory.

      That’s how evolution works: it doesn’t “constantly improve”. It only drives populations to change a trait when there is a real disadvantage to NOT having that trait.

      And some species don’t NEED intelligence. A single fly will have hundreds of children whether it is smart or not — there is no practical use to it being smart. The same argument goes for lions, and many others. Starfish haven’t changed for millions of years, not because evolution has “stopped” somehow…. but because starfish reproduce just fine. They don’t have any environmental pressure to change…. so they don’t.

      Hope that helps! Thanks again for your question.

  16. Zo0tie says:

    “Why did only humans become intelligent?”

    Duh! Because humans are the ones defining the word ‘intelligent’

    • Greg Stevens says:


      This is a cute answer, and I’ve heard it before. I think I remember a stand up comedian from when I was a teenager saying, “I used to think the brain was the most fascinating organ in the body, and then I realized… look what’s telling me that!” LOL

      However, to be serious for just a moment: even if we set aside the term “intelligence” for a moment (and all of its baggage), there are certain mental abilities that humans have that other species do not. Systematic symbol manipulation, for example. Language with grammar rather than just signs-and-signals. It’s a legitimately interesting question to ask why humans have this ability and others do not…. however, I do not think it’s “mysterious”.

      Certainly not so “mysterious” that it somehow “debunks” all of evolutionary theory. It’s merely an interesting question.

  17. Den says:

    I’m not convinced, let’s skip the well known scientific observation, experimentation, and verification methodology for a second, evolution shall not pass the status of remaining solely as an hypothesis, in my opinion such as million others would agree; […]

    […] you’re trying forcibly to impose the idea that “intelligence” and “extremes” are synonymous terms, and they are not, intelligence is a unique feature or set of features that distinguishes us (AND ONLY US) from the rest of the 8.7 million other species, and all set of features e.g. tallness, hugeness, fastness etc. or “extremes” as you wrongly refer to are not unique, tallness, hugeness, fastness are shareable between countless number of species, […]

    • Greg Stevens says:

      Thank you very much for the comment you left from your masked email address and United Arab Emirates IP address. Unfortunately, I had to edit out some of your language. I encourage people to disagree with ideas on here, but name-calling and rude accusations don’t further the debate. What I have left of your comment, however, is really the core of the point you seemed to be making: that intelligence is a binary (yes/no) trait, and humans are the only beings that have it. Let’s talk about that.

      I’ll start by acknowledging that it all depends on what you mean by “intelligence”, I suppose. It certainly is a sponge-word, and people use it to mean all kinds of things. Even among scientists who study “intelligence” there is disagreement.

      When I said that we lie on the “extreme” end of a continuum, I wasn’t intending to be “deceptive”. I was simply using the term broadly in a way that people do commonly use it: cats are “smarter” than slugs, and monkey are “smarter” than cats, and people are “smarter” than monkeys. Some scientists have even discussed the fact that knowledge and reasoning in its simplest form can be understood as existing in all living things. Intelligence is often associated with adaptiveness, learning, and creativity: and many types of animals exhibit these traits in varying degrees. In that sense, we are an extreme on a continuum.

      However, what I suspect you are talking about is the one thing that scientists HAVE isolated as being unique to people: syntax-based (i.e. grammatical) symbol manipulation. Even the chimps that learned sign language were never able to get grammar or sentence structure, and there are many people who think rule-based symbol-manipulation is not only at the root of generative grammar structure, but is also at the root of our development of mathematics and all of the kinds of abstraction that have given rise to scientific thinking itself. Not everyone agrees, but I personally think this is a likely hypothesis: whatever it was that allowed us to think in terms of abstract symbolic relations was the key that unlocked the great explosion of culture that we’ve experience in the last 10K-20K years.

      And I’ll also admit this: we don’t yet know how that particular mental capacity works, or why/how it came about! It is a fascinating, awesome question that many people are working on!

      Yet I’d also urge a little caution about what conclusions you draw from that. It seems like a bit of a leap to say, “We don’t fully understand how this one particular capacity happened” to the conclusion that you seemed to be pushing in your original comment: the idea that evolution is a “lie”, and so on and so forth. All it means is that we are working on figuring things out. Certainly, as the saying goes, “the lack of evidence isn’t evidence of a lack”, in other words: the fact that we haven’t developed a theory yet isn’t evidence that there is some kind of “problem” with the evolutionary framework for approaching our understanding of the development of life on earth. If you want do demonstrate that, you’ll have to come up with something a little stronger than: “There are still some things that you don’t know!”

      I’ve actually talked about this in my article, “Quasi-crystals are not proof of intelligent design”:

      • Den says:

        […irrelevant stuff about “freedom of speech” removed…]

        this issue is invading our life and discredits our way of thinking and stealing our children’s minds, that’s dictatorship in the flesh!

        […more anger removed…]

        Have a good day.

        • Greg Stevens says:

          Have a good day! 🙂

          • nolan kean says:

            Stealing children’s minds by encouraging people to think and question rather than accept we were “created” by “god”? Religious people refuse to even acknowledge that if “God” exists it isn’t at all how they perceive it or what they perceive it as.

          • nolan kean says:

            Language and Communicating had to have been crucial in human development. I’m guessing our brain hasn’t changed much over time, and that our ability to reason and have conscious thought put us at where we are today.

            If a human baby from 10,000 years ago were raised today I believe it would grow to be nearly as smart as todays humans.

            Humans can grow up in the wild and act like an animal, savage and unable to communicate, but our ability to teach each generation of kids as much as we know gives them the opportunity to learn and understand more than their parents.

            Humans can be surprisingly intelligent, or surprisingly unintelligent.

      • Cain says:

        Quite interesting how the author stated everything we already know and explained nothing.

        Of course we know we’re more intelligent than a fish and a worm, but why did no other animal evolve to such intelligence as ours? Why haven’t monkeys evolved to speak if they’re actually more intelligent than some politicians? Why are all other animals stuck or at least seem to be stuck where they are? Why are WE stuck?
        Has evolution stopped? Shouldn’t we all be Einsteins by now?

  18. feri says:

    Further more, How many real different species of Whales, with strong diferent features exist nowadays? (50? 60?)
    And i am talking of different important features, not just skin color or asian eyes?
    Evolution cannot explain human brain evolution and its uniqueness.

    • Amgaa says:

      The fact is that we homo sapiens are only survived species in homo genus. Only 12000 years ago there were other species of homo genus coexisting on the Earth. Most homo species such as neanderthals are mostly driven to extinction by us, due to the competition for food.

  19. feri says:

    You forgot one important deference:
    Those extreme abilityes like size on Whales or wings on birds, have been quite relatively very common in many many many different species, hundreds if not millions counting Dinosaurs, whereas intelligence at our level no animal known has even get close.
    Only 1 specie? o 3 or 4 counting the past Homo habilis, Erectus, etcc…
    It does not fit with evolution.
    Either we are a survivor from a different time on Earth, or some special event of which we still have no clue intervined (Not meaning necesarily God or Aliens, but why not?)
    I am just saying as you recognized, that Evolution right now cannot explain, neither does religieon or Alien theories.

  20. C.B. says:

    Let me start off by saying that I am a theist, I believe in evolution, but I don’t think it’s a good idea in general to use God as a way of explaining the puzzles of science, including evolution: I think that God doesn’t often specially intervene in the world, so when we say “God specially intervened to make it that way” to explain something, we are typically wrong and are cutting ourselves off from the causal explanation. All that to say, even though I am a theist, I am very sympathetic for the search for a naturalistic explanation of human intelligence.
    But I don’t think you have given an adequate one. Yes, we can see how less intelligent beings are likely to be at a disadvantage compared to more intelligent beings, but humans are amazingly intelligent compared to other creatures. As you say, the human brain is amazingly complex–it’s the thing that makes us capable of appreciating novels, making movies, and speaking lots of very different highly specific languages. (By highly specific I mean that in the right sort of environment almost every baby will grow into a person who can understand the difference between “your great-grandmother would have loved to have witnessed your wedding” and “an old female family member is over there in the church.”) Compare that language ability to the language abilities of the most highly-educated (i.e., favorable environment) apes. The human capacity is astounding. Why should the human brain have evolved to enable that sort of high-level complex thought? What were our ancestors doing 100,000 years ago that made those who lacked the sort of brain that made this sort of thought possible less-likely to survive? The size of our skull does not explain the remarkable complexity and capacity of the human brain anymore than my possession of a finger explains why I am wearing a diamond ring. Chalking the development of the brain up to chance is as unenlightening as the God hypothesis.

  21. Moamen says:

    Nice reply. However I still believe that humans are intelligent in an unordinarily way , and that has to have an explanation either god or another type , simple randomness isn’t a scientific explanation. Your example of the bowl of organs , we can assume that the force you did to throw them is evolution , now your force will set these oranges in random close motion on the table , if one of them fall down, then the thing caused it to fall wasn’t your force it was gravity which is an outside factor , factor that is unordinary to other oranges. However if your assuming that evolution has no outside factors , then you should replace the table with a floor so every orange get the same chance. If you throw a bowl of oranges into a floor , Im very sure that the area they will fall into will be close, you wont find an orange next to you and another one going to another country. And as for giraffes having long necks , there are many other animals with long necks such as horses, lama, etc. No matter what animal you get an example of , there is always another animal that are close to it. However the gap between human intelligence and all other millions of spices is for certain something unordinary and has to have a scientific explanation.

  22. Siddharth Kanwar says:

    I agree with what you have written …but I have one question too…
    As you said everything was random…according to environmental pressures..all evolved differently….and we evolved intelligently …but isn’t the gap of intelligence between us and other animals too much from a large no. of organisms evolving intelligently ?like in stronger terms…tiger and lions are almost equal…faster..also leopard..wild dogs like ??? why there couldn’t be no match like us ?

    • nolan kean says:

      Some People are 5 feet tall, of all colors and some people are 7 foot tall in all colors. Monkeys kind of look like us… its not like everyone is the same.

  23. Siddharth Kanwar says:

    U rock Greg !!!…awesum explanation !!..
    I was wondering about the same thing from many days…rather became so obsessed to find the answer..but trust me u gave me the answer I wanted …Thanks a lot !!!…

  24. Rafeh says:

    “Are you trying to imply that if the theory of evolution were true, then it “should” have produced more than one species with our level of intelligence? I’m not sure exactly why you would think that.”

    Because the probability is that high?

    Theory of evolution is retarded. Scientific fantasy to be the very best. Connecting dots from every matchable data with unlimited assumptions.

    Software Engineer

  25. Gordon Farkas says:

    Ok, so humans are not the only intelligent beings out there. Theres clever octupuses, dolphins, chimpanzees etc. Some animals even use tools. But why are there only a handful of species with intelligence – and then the extraordinary case of humans having intelligence an absolute quantum leap over all the others. If you were measuring it on a scale in a race, the lesser ones would sit around say the 100 metre mark, maybe go as far as 500 metres, but hey look – theres the humans at the 65 trillion trillion km mark. The human ability is so infinitely unique and advanced in comparison to any other species (on earth anyway). Why is that ?

    • Greg Stevens says:

      Maybe I wasn’t clear in my post, but I did try to address that question very specifically.

      There are lots of species out there that have extremely, “infinitely” unique traits. Giraffes have uniquely long necks. Giant squids have uniquely long tentacles. Barnacles have uniquely long penises. And so on.

      The process of variation and selection during evolution is actually very well suited to generating different species that are all unique in different ways. It’s a matter of adaptation, competition, and selection. Humans began being a little more intelligent than their competitors, which allowed them to advance faster and drive out competition… leaving them as being “uniquely intelligent”.

      Looking for a specific reason, after the fact, for humans being “different” is really a fundamental mistake in the way that you are thinking of the process of evolution.

      As I said in the article: you dump a bowl of oranges on a table, and one of them falls on the floor. You could spend a lifetime analyzing that one orange to figure out “Why did THAT SPECIFIC orange fall on the floor?” and “Why just THAT orange and not the others?” and “What makes THAT orange unique?”

      But it’s a misguided question. That’s simply the orange that happened to be the one that fell on the floor. There is literally nothing more to it than that.

      • Harsha says:

        Thank you for all the useful information. It was great!

        The fundamental misunderstanding lies in our definition of the term “intelligence.” What do we mean when we say humans are more intelligent than monkeys? One way to define intelligence is ‘the ability to predict future.’ If you can give me the situation now, I can use my laws of science to predict the situation at a later point of time. Other animals cannot do that. So, that makes humans more intelligent than other species. If this definition is convincing to you, we shall see that it immediately leads to a problem.

        The idea is that if you can predict the future, meaning if you are intelligent, you can manipulate the environment right now to suite your requirements at a later point in time in the future. Then the species that are intelligent have a better opportunity to survive and mate and hence should be the dominant ones. But, we do not see that in other animals.

        To take your example, giraffe: their unique trait is to have long necks. But, if an intelligent species has a better ability to predict future and therefore survive more, why didn’t every species become intelligent (with the same definition)? It seems artificial to me that ‘we’ are the only ones who are intelligent on this entire planet.

        There is nothing actually random about this universe. And to mention about your example of bowl of oranges on a table: If you can give me every possible detail of how you have placed the oranges, their volumes and how the bowl is structured, how you are applying forces on each orange etc., I can use the laws of physics to determine exactly which orange is going to fall off. There is nothing random about this. The mere lack of sufficient information makes things look random.

        And please do not think that I do not believe in evolution. I am an atheist and it is the only theory, by far, that gives a logical explanation about the origin of species.

        Hope you answer my questions,

        Thank you.

        • Greg Stevens says:

          Thanks for your comment!

          The core of your question seems to be this: “if an intelligent species has a better ability to predict future and therefore survive more, why didn’t every species become intelligent (with the same definition)?”

          But that kind of question is based on a misunderstanding of how the selection process works. Better ability to build counter-factual simulations of possible world / possible outcomes (i.e. “predict the future”) is a pretty cool trick, but it doesn’t automatically follow that it will improve the reproduction or survivability of every single species on the planet.

          Intelligence qua prediction is really just like any other trait. Some birds have strong beaks, some have weaker beaks. You could easily say “having a stronger beak will always make it easier to crack open seeds and nuts, therefore why don’t they evolve to all have strong beaks?”

          But the answer to that question (clearly) is that if having a weak beak is good enough to get the birds fed in their current environment, the stronger beaks don’t really confer any FITNESS advantage. Sure, birds with stronger beaks may have life a little easier … but they won’t out-survive or out-reproduce birds with weaker beaks. So, there is no reason for evolutionary pressure to increase the strength of beaks over time.

          Similarly, if I’m a lion — at the top of my food chain! — I can accomplish everything I need to by being fast and strong. Sure, I might be a little fatter and happier if I also have a good memory, or can anticipate which way the herd of prey will move tomorrow. But unless there is enough scarcity that the lions with bad memories are DYING OFF, there is no evolutionary pressure for memory to improve.

          Do you see what I mean? It’s a core flaw in the logic of how you understand evolution, to assume that just because something seems like “an advantage” in the abstract, that it will automatically incur a fitness advantage in the survival/evolutionary sense.

          • Harsha says:

            Thank you for your reply.

            I understand what you are saying. So, you mean to say that the species which can survive very well in a particular environment with a particular trait has no need to change its way of doing things. And, nature does not give any particular importance or privilege to any single trait. Its all about survival.

            Thanks a lot for clarifying my doubts. I appreciate it very much.

          • Greg Stevens says:

            “So, you mean to say that the species which can survive very well in a particular environment with a particular trait has no need to change its way of doing things.”

            Yes, exactly! And thanks for your question, I’m glad I could help clarify that point.

  26. Ahmad fares says:

    I have to thank Western civilization on the wonderful and amazing things like the internet

  27. Ahmad fares says:

    The complexity of the process of reproduction through Male & Female,That isn’t simply,No need to Creator,Improbable
    What can you say about that ?

  28. Ahmad fares says:

    Thank you, I appreciate your efforts, I wish you well

  29. Kirk says:

    I am glad to see this being discussed in a such a civil and informative manner!

    The evolution of the human mind has always been tricky to understand, mostly because it is a very complex system and therefore will have complex evolutionary pressures. Often too, these pressures changed different parts of the body that then had a trickle down effect on the mind. (I think Greg did a phenomenal job at explaining the logic of evolution, so I’ll not go into it).

    Greg hit on one aspect of cognitive evolution (I don’t like the term intelligence. If you’d like to know why, I can explain it further in another post): the psychological concept and the environmental pressure to evolve and sustain that level of psychology. But, the evolution of mind has always been a chicken-or-the-egg discussion. Greg very effectively explained how the evolution of the mind is molded by both need and detriment, i.e. the egg. But his argument can also very easily be extended to the biology, i.e. the chicken, that supports our mind and I find this helps folks understand even more.

    The mind is after all a byproduct of our biology: namely, our brain. We have a brains that are on the larger side (in terms of our over all body mass) compared to other animals. More importantly, we have one of the most structurally complex brains in the animal kingdom and this level of complexity gives rise to our ability to be so cognitively capable. Like the giraffe’s neck, our brain’s structure is a physical extreme that has evolved to make us better able to survive.

    Unlike the giraffe’s neck, though, there are lots of influences on how the brain got so complex (though I mean not to discount the giraffe’s evolution). For example, in order for us to have such a large and complex brain, we need a skull that will accommodate it. And we’ve got a lot of space in there! The skull’s shape and musculature is in itself molded by environmental pressures and ours took a weird little turn quite some time ago: our jaw structures began to shrink. In the same way giraffe’s got their long neck, as Greg mentioned, our ancestors with smaller jaws were at some point better at exploiting the environment and able to live on, while those with bigger jaws died out. The important thing about the big jaw was that it had huge muscles that moved it. Think about that muscle as a REALLY strong bungee cord: in order for it to work, it has to have something really strong to attach to. In the muscle’s case, it’s the skull. For the skull to be strong enough, it had to fuse all of it’s bones together very soon after birth and also needed be very thick for the outside structures to adhere, leaving little space in the middle. At that time, those that were born with thinner skull bones or bones that didn’t fuse fast enough would die. But, once the structure of the jaw began to change and get smaller to accommodate the dietary environment, the skull changed with it. Those with thinner skulls and skulls that fused together slowly were then able to survive and out perform the big jawed folks. These newer skull structures allowed for more space in the middle of the skull and the brain was able to get bigger and more complex. Because of it, we were able to figure more stuff out. The brain is really interesting in the way, because the more we figure stuff out, the more connections our brain makes within itself. If you make more and more connections over the course of millions of years, the more structurally it will become and the more cognitively it will be.

    Now, this is not the only theory and I have reduced it quite a bit. But, I think it provides a good example as to how evolution works as whole and illustrates how intricately evolution may have shaped us to be so damn smart.

    Hope this helped shed more light on it 🙂


    • Jesse says:

      Kirk its true what you say, it is nice to engage in healthy discussion. I would like to add to it.

      This is as much a question as it is a proposition, as I am no expert; is not the essence of cognitive evolution insofar as human beings are concerned an issue because of the sheer magnitude of difference between human intelligence and that of other animals. Now I know you conformed to references of things like, in that you agree that they are an example of the ‘extreme’ biological differences to be found amongst animals: Giraffe’s necks, Whale’s size etc. However, as long as a giraffes neck is in proportion to its body, even if we compared it proportionately to our body size – neck length, the proportionate difference in neck length is dwarfed by the size of the difference in cognitive ability. If a Giraffes neck is ten times bigger than ours proportionately or even twenty times, we are a thousand times more intelligent than them.

      Don’t think that by that I mean that as a result of this, we can only conclude that evolution can’t explain human intelligence – that would just be silly. What I mean is that intelligence or cognitive scope or ability is not the same as the length or size of our bodies. Yes, they are both biological, but they are very different. If they weren’t, then we would understand considerably more about the brain would we not?

      Something else: It is a mistake to for anyone to suggest that we became so advanced cognitively purely in order to survive; that only the smart people survived. Do any modern evolutionary theorists actually believe that our sense of self, our Ego, our conscious was necessary in order to survive? That only those people who were able to philosophise about their existence in respect to the universe were able to survive. The more examples we think of the more absurd it becomes. If it was purely down to that then we wouldn’t be as cognitively capable as we are, nowhere near in fact.

      Another issue is how rapidly we evolved in terms of our intelligence. 100,000 years sounds like a long time but it isn’t, certainly not enough time for so many changes to take place, so many changes that created such a monumental difference in intelligence between animals and human beings. 100s of millions of years of life on earth, the most intelligent life to that point would have been no more intelligent than a chimp is today (raptors were intelligent too), but then all of a sudden, in a mere 100,000 years human beings intelligence becomes far far far superior to any animal. (in 100s of millions of years of life on Earth , why are we the only ones that became more intelligent? How did it happen so fast? ….There are no answers to these questions) (yet)

      One thing is for sure, its very difficult to explain with evolutionary theory, but I’m sure one day it will be. I would argue that there is something else at play here, such as the theory that magic mushrooms or something similar crept into the diet of our ancestors which broadened their psyche, but I’m not convinced by this.

      I simply make these points:

      1.) differences in size do not compare to differences in cognitive ability – nor does brain size really (fact)
      2.) the claim that our brains became this advanced purely down to it being necessary for survival is futile.

      Hope this gets a response


      • Greg Stevens says:


        You make some really good points, and I think I’ve read some other people who have made the same type of observation. Some researchers have suggested that there is some underlying mechanism–some CORE ability–that was the “threshold” that we passed that then end up giving us a whole host of other abilities as a natural consequence.

        So, as I understand it, the hypothesis goes something like this.

        It’s ridiculous to say that all aspects of intelligence evolved because they were adaptive. Many aspects of intelligence, ranging from imagining hypothetical alternative future universes to being able to write and love poetry, are so abstract it’s just tough to imagine an environment in which there was evolutionary PRESSURE favoring them.

        But, if we suppose that there is some core neurological or mental thing, like — let’s say, just for the sake of discussion — the ability to mentally represent and manipulate abstract mental tokens.

        Thus instead of being able to only learn

        S – R

        we were able to learn

        S – C – R

        Some people have suggested that that was a kind of “watershed” that then lead to everything else, like so many falling dominoes: generative grammar structures leading to language, abstract symbol systems leading to religion, storytelling and music, and on and on… a kind of runaway consequence of a simple change.

        That kind of story (and I’m by no means proposing the above example as a serious hypothesis, just a kind of “placeholder” for the kind of theory one might entertain) could be use to explain why intelligence as COMPLEX as we have has arisen, and driven us so far from other animals, even if all that complexity was never “required” per se by our environment.

        • E d says:

          Want too add something too anybody reading through this, why are we so “different” than other animals in terms of intelligence I would compare too the company ford 100 years ago.. was a small business in a garage. Then from there completely taking over and “dominating” any smaller and coming up company’s that would want too “extinct” them. If they let them work with them there probably would still be the other intelligent species.. but basically what I am saying is imagine being a teenager in a garage right now with some car parts and wanting too go up against “ford motors.” Or any kid with 50 dollars compared too Donald Trump.. look how insanely far apart this is. Why? Ford was there first and has since been progressing for so long and at the time keeping the others down too the point were knowbody else would have a chance.. how this could happen? Ice age maybe? Any big devistating event where the animal at the time that had the “intellectual edge” lived through and was the first elvolving this straight and because of this had a HUGE advantage

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