From a scientific (not religious) standpoint, what are (if any) the fundamental differences between humans and other animals?


In my opinion, there is no fundamental difference between humans and other animals at the level of biology. Hence, I'm not asking a biological question. I'm curious if there are any philosophical ideas about the fundamental differences between humans and animals from the perspective of our behavior, intelligence, abilities, special role/place in the universe, etc. Such ideas exist in many religions. For example, in Christianity god created man in his own image, men have souls, they have concepts of good and bad, they have the freedom of choice, righteous men will have eternal life in heaven, etc. Taking religious concepts aside, what does philosophy have to say about this difference? Or maybe philosophy doesn't acknowledge any fundamental differences between humans and animals?

  • This is definitely really interesting territory, but maybe you could tell us a little more about your concern here? What might you be studying or reading that has made this problem important to you? What might you have found out so far? (Telling the community about your context and motivations can improve the likelihood of getting a great answer; it also helps potential answerers frame their responses.)
    – Joseph Weissman
    Apr 26 '12 at 1:01
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    In addition to the concerns that have already been expressed regarding its vagueness, this seems like a biology question, rather than a philosophical one.
    – Cody Gray
    Apr 26 '12 at 1:55
  • we are (much) smarter and we are at the top of the food pyramid. Those are two main differences between us and them. And that's purely biological difference @CodyGray
    – c69
    Apr 28 '12 at 13:57
  • Closing for the time being pending some clarification of the context and maybe a little more specification of the concern itself
    – Joseph Weissman
    Apr 28 '12 at 17:40
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    How can it be "not constructive" with so many well voted answers?
    – Rodrigo
    Nov 12 '14 at 13:35

With your edit I will venture a guess as to a more specific question, which hopefully is similar to what you want to know:

Are there any morally relevant features which all humans share and no non-human has?

I emphasize "morally relevant" since it is a question for biology to list the anatomical differences, which is of course an important thing to do, but off topic here.

Phrased this way, this is the argument from marginal cases. Essentially, the claim is that so-called "marginal humans," such as those with severe cognitive handicaps, have mental capabilities similar (or inferior) to some non-humans. Quoth Singer (from Animal Liberation):

The catch is that any such characteristic that is possessed by all human beings will not be possessed only by human beings. For example, all human beings, but not only human beings, are capable of feeling pain; and while only human beings are capable of solving complex mathematical problems, not all humans can do this.

Dissenters from this argument generally embrace the view that the question is misguided: ethical value doesn't come from having some set of capabilities, but rather arises through a shared contract etc. Carl Cohen defends this view, for example.

Entire books have been written about this, if you are interested to continue researching it.

On other fronts, you might be interested in the work that Varner, among others, has done to describe the likelihood that various species feel pain which can be roughly summarized as "vertebrates feel pain; insects possibly not so much". And Dan Dennett expresses some uncertainty as to what extent non-humans are conscious, but of course he is quite skeptical of most accounts of human consciousness as well.


It is a bit difficult to get at exactly what kind of answer you are hoping for (philosophical yet scientific, yet not biological?) but that being said:

Without a doubt, humans shape their environment to a far, far greater extent than any other animal. While it is true that some animals have, from time to time, been witnessed making tools, these are rare exceptions. Humans, on the other hand, rely upon tekhne on a daily basis.

Also: humans are capable of far more complex communication than other animals. Again, it is not that communication is unique to humans, but that the level of communication is of such a profoundly more rich and subtle nature as to give rise to a shared conceptual world.

In other words: we have no way of knowing whether a given animal (say, a dog) has a consciousness that resembles ours-- but then again, neither does another dog, as it lacks the sufficient ability to communicate about its relation to the world, even to another dog.

  • I'd disagree with most of your answer. There are chimpanzees which use tools every day, some apes do seem to have a theory of mind, and some birds have quite complex grammar.
    – Xodarap
    Apr 26 '12 at 13:08
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    But as impressive as those examples are, none of them rise to the level of even .1% of the level of humans, and that's my point. They are comparable only in the way that paper airplanes are comparable to jet airliners. Apr 26 '12 at 13:50
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    Nevertheless they are comparable and thus not 'absolute'
    – Youss
    Apr 26 '12 at 13:51
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    I agree--but again, that's the point. It is not that there are any absolute differences between humans and animals, but rather, differences of degree which are of such a magnitude as to make a relevant distinction. Apr 26 '12 at 14:20
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    Some other animals may rely on tekhne, but a person does more to shape their environment in the course of an hour than an animal does in its lifetime. Dogs may indeed be conscious-- but their communication skills are not up to the task of communicating the richness of that consciousness to us, or to other dogs. These are sweeping generalizations, but I thought that is what the questioner was looking for. Apr 26 '12 at 20:04

Philosophy is constructed by various branches like biology and other scientific research. Without those branches, you simply can not formulate anything. So one would have to rely on those branches in order to make sense in philosophy.

That said, there is absolutely nothing that can serve as proof of any difference between man and animal in a philosophical matter. Everything that humans do can be explained by looking at there most fundamental causes like survival. It's these primitive emotions/tendencies that we share with the animal world and that are the driving force of everything we do. No matter how complicated our behavior might seem, in the end, it is simply a result of our primitive 'animal' configuration.

As far as I can see, the only thing that may serve as proof within the framework of reason is the ability to ask the question you asked in the first place :) In the end, it's all about our personal choice to ask ourselves these questions. Those who do are mostly very interested in their human identity and are often developing and shaping their understanding of this identity (mainly through religion I believe). Without asking ourselves these questions and thus 'creating' the 'thing' we call 'human', there is really nothing that separates us from animals.

  • Those are really far fetched claims, and obviously they fail miserably when faced with the reality of something as simple and common as self-sacrifice.
    – user1746
    Apr 27 '12 at 3:45
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    @Pedro Werneck Maybe you could try elaborating on your opinion next time, instead of just dropping one..Anyway, why are they 'far fetched claims'? And why do you think 'self-sacrifice' is not present in the animal world? Furthermore, 'self-sacrifice' can happen in a religious framework of which I sad is (probably) the one thing that separates us from the animal kingdom. It could also happen in an other frameworks like 'survival' or better yet; preservation of a group of people as we see in warfare, which is simply a complex form of 'survival (a primal/primitive tendency)
    – Youss
    Apr 27 '12 at 9:02
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    I don't see how self-sacrifice can act out without a primal tendency as belonging or preservation, survival etc
    – Youss
    Apr 27 '12 at 9:18

Perhaps it would be better to ask if anyone has any evidence of other creatures able to communicate about their method of thinking. Can they demonstrate traits of, or communicate about, metacognition? Since some apes have been taught to communicate on a somewhat sophisticated level enough to express lying, motivations, deceit, then are they able to express how they arrived at their strategies of action? If so, that would blur the line further. If not, then it would be one point of differentiation. This from Wikipedia:

"Metacognologists believe that the ability to consciously think about thinking is unique to sapient species and indeed is one of the definitions of sapience.[citation needed] There is evidence that rhesus monkeys and apes can make accurate judgments about the strengths of their memories of fact and monitor their own uncertainty,[9] while attempts to demonstrate metacognition in birds have been inconclusive.[10] A 2007 study has provided some evidence for metacognition in rats,[11][12][13] but further analysis suggested that they may have been following simple operant conditioning principles.[14] "

Many question whether these "judgements about strengths of their memories of fact" actually rises to the level of "metacognition". I tend to agree.


It would be really weird if philosophy didn't acknowledged any differences between humans and animals, since the humans are those doing philosophy, not the animals. One difference is how animals might be in doubt between two decisions like humans, but they won't get into the cartesian state of recursive doubt until they question the existence of an outside reality itself that makes them unable to act. If that state was a real experience from Descartes or just an hypothesis he poses as real is another question entirely.

The real issue with your question is that you can't talk about fundamental differences at the level of biology, only about differences in reaction to your biological experiments. There might be fundamental differences that aren't easily reproducible and might not be object of scientific experimentation, but they are perceived by men over time and have a symbolic relevance, leading to myth. Religious doctrine like those you mention are set in consequence of myth, and if you are really interested in knowing the fundamental differences, setting those aside is like a police investigator throwing away evidence that doesn't seem to be useful at the time.

Considering this, asking if there are any philosophical ideas about the difference between human and animals specifying the perspective of our behavior, intelligence, abilities and role in the universe taking religious concepts aside is absurd, since having those concepts is a major difference, and if not the most important and most studied in philosophy, one of the most. The religious ideas don't come out of nowhere, and as far as I know, animals don't do that.

Even if you try to set those concepts aside, they will come back in one way or the other, but you won't notice or you will be in denial if you assume they aren't relevant. For instance, you may set religious concepts aside and follow Singer's Animal Liberation suggested by another answer, which ultimately leads to the conclusion there's no fundamental differences between humans and animals. If that's the case and animals feel pain, then it's morally wrong for humans to explore them. However when we explore plants and destroy wildlife in order to plant crops, we are also putting ourselves ahead of the animals which lived there. We also don't know if the plants themselves don't feel pain and don't suffer, and the same reasoning applies. The obvious conclusion is that in order for men to survive, it has to cause suffering to someone or something, and its existence is inherently wrong in some way. You'll find that as a symbol in most cultures, and the myth from it leads to doctrine in many religions. Many cultures have an origin myth where men lived in a state of non-suffering, and then did something that lead him to a suffering existence. Christian doctrine calls it the fall of man.

If you set the religious concepts aside as if they weren't part of men's reality while doing a philosophical investigation, they will come back and bite you from some other side. It's inevitable. Notice that this has nothing to do with your personal religious beliefs.

You have a few good philosophers who investigated what happens with mankind when the fundamental concept of human and animal existence are reduced to the same thing, which is the other side of the utilitarian ethics from Singer and others. This relativization of the human condition is what Eric Voegelin ultimately links to ancient gnosticism and their modern siblings, communism and nazism. Voegelin might be a hard read, but Hannah Arendt's The Origins of Totalitarianism is easier, although the relation to your questioning might not be so obvious.


One philosopher and biologist said that humans have 2 difference when compare to other Primates:

  • bipedalism. I.e., using only legs to move the body;
  • the distance between the teeth. To be precise, it is important to the distance between the canines.

Also he noted that people have the largest brain's weight relative to body weight. Relative mass, not a absolute mass. Cause whale or something have the heaviest brain :) It is not fundamental difference, but interesting fact that should be noted.

Everything else of the humans are the same as the chimpanzee.

Please note that this is an opinion rather than scientific statement. So it is impossible to make a references to somebody's works.

  • 1
    Can you possibly provide a reference or citation for that opinion?
    – Cody Gray
    Apr 29 '12 at 4:32
  • I was talking specifically about the part where you said "One philosopher and biologist said..." Which philosopher and biologist? Where/when did they say it?
    – Cody Gray
    Apr 30 '12 at 1:40
  • Now I have no contacts with him. One Russian arcticle tells the same: thedifference.ru/otlichie-cheloveka-ot-obezyany It reference to second signal system and owning of mind, but it is not a good idea to mention these concept, cause they generate more questions than they could solve. May 2 '12 at 7:49

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