Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Discussion on consciousness

  1. Sep 30, 2003 #1
    i would like to begin a discussion on consciousness. some important questions about it are:
    1)what is consciousness?
    2)is it unique in humans or do other animals have it? if they do, upto what degree?
    3)how and why did it arise?
    4)how are humans(and other conscious animals)different from those who do not have it?

    i have some nebulous views of my own. but let's hear your's first. some useful links will be welcome.
    Last edited by a moderator: Feb 6, 2013
  2. jcsd
  3. Oct 1, 2003 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    For point two: I am very sure other mammals also have a conciousness. For instance my dogs: I can tell when they have done something that is not allowed, when I walk into the room, by the look on their face. They know very well that they did something that was not allowed and that if I find it out, they'll get punished.

    They see a relationship in time.

    I once saw a video on the "america's funniest home videos" there was a dog, a pool, and the boss with a ball.

    The boss threw the ball in the middle of the pool, the dog ran after it and I thought the dog was going to jump after it.. the moment it reached the edge of the pool it halted abruptly, tried to reach the ball, walked around the pool to see if somewhere the distance was shorter, then he walked to the far end of the pool and to my stupid amazement, the dog jumped on a floating board, started peddling with its front paws, made its way to the ball, picked it from the water, peddled to the edge of the pool and jumped off.

    I couldn't believe it since this is very complex behaviour and requires thinking and a conciousness.
  4. Oct 1, 2003 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    What is conciousness, that is a very interesting question too. I'd like to see that answered physically (to relate this topic to biology).

    Are there any case studies where humans lost this ability (I wonder how you'd define such a person.. comatose, inresponsive, able to interact?) and that the damage was inflicted by a stroke, so that the regions implicated in the formation of conciousness can be pinpointed.

    I have got a very interesting book at home: "Phantoms of the brain" by Prof. dr. Vilayanur Ramachandran and Sandra Blakeslee. The title in my language says translated: "The bizarre brain: what errors in the brain teach us about the function thereof". I would highly recommend it, it is very entertaining to read and the subjects are very novel, he talks about case-studies of patients who he has seen in his carreer.
  5. Oct 1, 2003 #4


    User Avatar

    Staff: Mentor

    Does thinking require consciousness? I'm not so sure. Very few dogs can pass the "mirror test" - recognizing themselves in a mirror.

    The ease at which a dog can be imprinted upon says "stimulus-response" to me, not intelligence.

    Ants have fairly complex behaviors as well.

    In any case, this is very similar to another thread on the same subject.
  6. Oct 1, 2003 #5
    Here is an excellent site that discusses consciousness and the brain in detail:

    NOVA Online | Secrets of the Mind | The Electric Brain
  7. Oct 1, 2003 #6

    I think that, like the word "energy" or the word "life" the word "consciousness is best understood with examples and descriptions as opposed to trying a direct frontal definition.

    It seems to me that in order to be conscious a thing must have sences of some kind for recieving information from the outside world
    and it must have some sort of processor for that information, a "brain" of some kind where the information is used to formulate a responsive behaviour.

    I think everything down to bacteria is conscious. I'm not sure about viruses. Lower down things are just chemical reactions that are occuring without any awareness on the part of the chemicals involved.

    Things get more tricky when it comes to plants. Some people claim plants are conscious. This doesn't seem likely to me, but I dont see any way to prove or disprove it.

    Since consciousness depends on information from sences you could expect that the consciousness of a dog would be very different than that of a human given the differences in the sences of a dog: black and white vision, superior hearing and sence of smell, that we know of. Most animals have sences we do not. I was amazed to read that some birds can see with light in the ultra-violet range, for example, and that snakes of the "Pit Viper" class have infra-red sensors on their faces which allow them to sence mice at night from their body heat.

    Dogs and ants are certainly conscious but it would be a mistake to think this means they are like people in a dog's or ant's body. Their brains are designed to make sence out of things according to the kind of sences they are endowed with. Our brains wouldn't be able to make any kind of sence from the sort of imput they recieve anymore than theirs could make sence of the imput humans recieve.

  8. Oct 1, 2003 #7
    I suspect it is the stimulus/responce, stick a pin in a cell, and it reacts, hence the belief that it is (sorta) "self aware"
  9. Oct 2, 2003 #8
    i did not know a similar thread already exists in this section. will try to find it. as all of you see there are disagreements about who is conscious and who is not. if one defines consciousness as the ability to take in, process and act on information from the surronding then such attributes are present in all animals(let's leave out plants for the time being) albeit in varying degrees. when Geoge(say) is conscious of the presence of a delicious steak in his kitchen, his dog is conscious of it to, ditto for a fly outside George's window. and what each will do is also obvious, all three will try to eat it in their different ways. if one says however that to be conscious means one must be able to detect itself as a part of the surroundings one is studying, then things are a bit tricky. this is where a mirror test comes in. but what are we to infer when an animal fails mirror test? that it cannot detect itself? but how can a dog not detect itself? it has eyes, it can certainly see its body, so?
    some say consciousness is the idea of I. so what is so special about that? George calls Bob, Bob; Nancy,Nancy and George,I.if one can detect something you have to give it a name, that much is obvious. a dog cannot recognise that the dog in the glass is itself, a hen cannot recognise that a baby crane inseted as an egg in her original clutch is not her chick though it is twice as big as her mother. call them stupid but how can we say they are unconscious?
    Last edited: Oct 2, 2003
  10. Oct 2, 2003 #9


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I believe a very important consideration in any discussion of consciousness is the phenomenon of blindsight, a sort of deficiency of consciousness caused by lesions to certain areas of the brain. People with blindsight are 'blind' in certain areas of their visual field, insofar as they do not have visual awareness in these areas. Yet if you observe their behavior in interacting with objects in these blind areas, you will see that it is pretty much indistinguishable from that of a normally functioning person-- they can answer questions about the objects, reach out and grab them in a fluent manner, etc., despite their claims that they can't actually 'see' what is there.

    This tells us a couple of important things. First of all, intelligent behavior is not necessarily a reliable indicator of an underlying consciousness. Second, blindsight seems to indicate that consciousness is a complex process dependent upon an array of brain functions working in harmony with eachother-- which at least hints at some sort of requirement of a 'sufficiently complex' information processing architecture in order to sustain consciousness. This notion backs up the intuition of a 'spectrum' of consciousness existent in life, where in general the more complex the functioning of an organism is, the more 'aware' it is. So it is natural to attribute consciousness to a chimp, but pretty dubious to attribute it to a paramecium or an ant.

    More on blindsight: http://serendip.brynmawr.edu/bb/blindsight.html
  11. Oct 2, 2003 #10
    I'm not clear exactly what you mean. There would be a difference between intelligent behaviour and intelligent looking behaviour. Driving a car, for example, looks like it involves alot of intelligence. In fact, the more one drives the more "automatic" driving can become. Regardless, it is highly dependent on consciousness of the circumstances to drive properly.

    I would have to disagree with the premise that information processing preceeds and sustains consciousness. I think consciousness comes first.

    The "intuition" is crippled at the start in so far as it requires consciousness to be of a human quality. The spectrum, a product of human imagination, can really only be said to be a spectrum of more human to less human. One could just as well come to the conclusion that humans, because of their complexity, are more diffused and watered down than other life forms. Scattered as it is over so many considerations, our consciousness may never be as sharp and focused as it is for a dog on the scent of a rabbit. The paramecium because of its even greater simplicity, may be able to experience awareness (of whatever it is aware of) with a with a poignancy inconcievable to the dog.

  12. Oct 2, 2003 #11
    Actually, the people I'm thinking of who make this claim aren't anywhere near that scientific about it. It is something you hear from the people who talk to their plants. They claim this makes them healthier, and they grow faster. House plants and garden plants alike.
  13. Oct 2, 2003 #12


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If you want to make a distinction between intelligent behavior and intelligent looking behavior, then the latter is all that applies in this discussion. We can only say of a certain animal that its behavior looks intelligent-- eg, with Monique's example of the dog in the pool. Intelligent looking behavior is clearly a criterion we need to take into account when deliberating on whether a given animal is conscious or not. We just need to recognize the limits of such an approach. In the case of blindsight, if we said that the person's intelligent looking behavior implied that he was conscious of the things he was intelligently interacting with or talking about, we would be wrong. Thus, we must recognize the fact that intelligent looking behavior can exist without conscious guidance, and so is not necessarily a reliable indicator of consciousness.

    Certainly possible, but taking such a view restricts any rational conversation we can have on the matter. If you think a bacterium is conscious, then it's not at all clear why an atom or an electron would not be conscious in some way either. I think, from a logical standpoint, that it's a better approach to start from what we know, ie that humans are conscious, and work from there to try to deduce or intuit what is going on.

    Again, I can sympathize with your points here, but at this stage at least we need to start with what we know. If a certain being is conscious but not in any sense analogous to human consciousness, then we really can't know anything about its consciousness, or if it even makes sense to call this being's quality "consciousness" at all.

    If we restrict our attention exclusively to the notion that brain lesions can destroy parts of human consciousness, then blindsight is only one of many examples. What these all indicate is that human consciousness is a function of the interconnectedness and activity of the brain. As such, it makes the most sense at this point in our understanding to view consciousness and brain activity as equivalent phenomena. From this proposition, in conjunction with the recognition that intelligent (looking) behavior can be the product of unconscious processes, we can begin to make vague claims of the 'spectrum of consciousness' sort.
  14. Oct 2, 2003 #13

    I agree. This is only important to humans, and if it is being applied to animals as a measure of consciousness it is an erroneous method. A cat or dog may not have the neuronal wiring or kind of lobe it takes to form a conception of the existence of an external image of itself, but that is not a measure of it's consciousness.

    The way information is processed is not a measure of degree of consciousness. Yesterday I read an autobiographical story by a high-functioning autistic woman whos language developement was greatly delayed by the fact she didn't realize the noises people made with thir mouths were a form of communication untill she was six or seven. She was perfectly conscious of these noises but she assumed they were a form of play: something people did for the entertainment value of the sensations it produced.

    In the same way a cat or dog looking in a mirror is completely conscious of the image that seems to follow their every move, they simply don't seem to have the circuitry it takes to form the important connection between that image and themselves. It's not a "lesser" consciousness. It's a different kind of consciousness.
  15. Oct 2, 2003 #14
    So, I am correct in supposing you would edit your original statement:"First of all, intelligent behaviour is not necessarily a reliable indicator of an underlying consciousness," to read "...intelligent looking behaviour..."?

    You have jumped to a conclusion about the blind sight situation here that may not be accurate.( I went to your link, but didn't find it wet into any more depth than I already was familiar with.) My guess is that this condition arises when the dominant hemisphere is cut off from the visual processing centers, while the other hemisphere remains connected. In most people the dominant, language, hemisphere is the left. This is the side you would be talking to in a full split brain patient.
    In the blind sight people, this side is blind It is not aware of any visual imput. Visual imput, though, is still getting to the non-dominant, mute, hemisphere
    which can still act upon what it sees despite being unable to utter a word about it or to get the information over to the left side which can still talk.
    What this means is that the person is conscious of what he is seeing - there is authentic awareness there - but there is a disconnection between that aware side and the side that talks to others. (I would guess, too, that the side which can see is probably experiencing only half a visual field - only recieving input from one half of each eye.)
    Not yet. The blind sight example is probably not a proof of this.
    I have not come across any examples of intelligent looking behaviour where an absence of consciousness was shown to be the case.

    My criteria for consciousness is that an entity must be able to recieve information from its environment via some kind of sence mechanism, that it must have the means to process that information, something that we might call a "brain", and be able to formulate a deliberate response. Based on that I wouldn't suspect atoms and electrons of having consciousness.
    The simplest I would go with confidence is bacteria.
    I don't think there is an alternative to starting with ourselves. It is essential, though, to avoid the assumption that in order to be conscious other beings must be conscious in the same ways we are, to do some serious wondering about how different our experience of the world and ourselves might be if, for instance, we had no color vision.

    We can never know details for certain, but the same is true about our view of other people, yet we generally grant consciousness to all other humans.
    I was not suggesting that the consciousness of a paramecium is "not in any sence analagous to human consciousness". It is safe to assume that if it is conscious it experiences something like desire, at least, to eat, to move from discomfort to comfort, etc. And perhaps other things. Whether or not we can call it consciousness is at this point more dependent on a mutually satisfactory description/definition.

    The thalamo-cortical network is critical to consciousness in humans. The thalamus, a very small
    set of organs, seems to be the essential, sine qua non of this duo. This circuit can be gotten into from the cortex of the frontal lobes, but it isn't till trouble reaches the thalamus that consciousness is lost. You can disturb huge areas of the brain, and huge numbers of the connections but consciousness will not be lost untill you interfere with the thalamo-cortical network.
    Agreed, which is why my criteria includes some thing that functions as a "brain".
    I'm agreeing on the requirement of a brain, but not on the existence of intelligent looking behaviour that is devoid of consciousness.

    My speculation that the simpler, more concentrated focus of a dog on the hunt might represent a more intense consciousness is really just extrapolating from human experience, which is what you are calling for. To say people are more conscious because we can talk and drive a car at the same time may be to miss the fact that both activities are much dimmer than either would be if we were just dedicated to one or the other, as a dog is when chasing a rabbit.

  16. Oct 3, 2003 #15
    self conciousness?

    I think up to know 3 animals passed the mirror test: human, chimpansee and dorphin. They recognised paint on their face in a mirror as being paint on THEIR face. Other animals rather attack the mirror. What confuses me is the dophin: he is not directly related (in an evolutionary way) to homoids. I think 2 possibilities arise: conciousness evolved twice in the mammal evolution, or the species between Cetaceae (Dolphin e.o.) and Homoids do have conciousness.

    I heard a rather intersting story from a Dutch professor. Sorry, I have no name nor link or whatsoever. It's a theory anyway. He states that conciousness is not situated on 1 place in the brain. Inputs are crossing around, and the "one with the highest input gets the attention". He compared this to his talk. During his talk he was "focussed" on his presentation, his memory. But suppose a hungry lion would walk in, a new inpuls would cross his mind and would easily defeat the impulses from his memory. He would stop talking and start running! I think this is a nice start for explaining conciousness (of course it's just a concept). It explains f.e. that nobody really found the "conciousness" nucleus in the brain, because there is none.
  17. Oct 3, 2003 #16
    Re: self conciousness?

    It is certainly true that our attention can change focus, but this does not mean that there are many different centers in the brain, all independently conscious.

    The thalamo-cortical complex is most definitely the "seat" of consciousness in the brain. You can disturb any other parts of the brain without a loss of consciousness, but not the thalamo-corticle complex. Conversely if the thalamo-coricle complex is disturbed it does not matter how much of the rest of the brain is fine: there will be no consciousness. That would not be the case if the dutch professors speculation about consciousness existing in all parts of the brain
    held any water.
  18. Oct 3, 2003 #17
    so what exactly happens if the thalamo cortical region is damaged? does this region exists in other animals. i'll be away for a week. continue discussion.
  19. Oct 3, 2003 #18


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Yes. In fact, if you make a distinction between intelligent behavior and intelligent looking behavior, the only thing one can observe in beings other than oneself is of course the latter.

    I'm going to address this in a separate post.

    Fair enough, but consider for example the knee-jerk reaction. There is certainly not consciousness involved in this behavior. Couldn't a bacterium operate in a similar way, responding to its environment without necessarily being aware?

    By your criteria, every cell (or at least major organs) in a human person's body would be conscious, in addition to what I suppose would be the more macroscopic consciousness of the brain that we normally identify ourselves with. Similarly, if we view individual humans as 'cells' of the society as a whole and take a liberal view of your definition, then this society itself would be able to receive information from its environment, have a means of processing information, and be able to formulate a deliberate response. Does this make an entire society an entity which itself is conscious? If not, what are the physical restrictions that prevent it from being so? Are these sensible and derived by logic or more or less arbitrary?

    I definitely agree with this.

    Yes, but the further we get from beings who function on the same overall principles as ourselves, the more in general we must call into question any similarities between the two. Specifically, I don't know if there's anything about assuming that all normally functioning humans are conscious that should entail something like a bacterium also being conscious.

    The most sensible criterion I have come across is Thomas Nagel's: is it 'like something' to be a certain creature? If so, that creature has some form of consciousness; if not, it has no consciousness. This criterion arises from the notion that consciousness involves personal experience of subjective qualia, such as a color or a sound or a thought. We can meaningfully say that it is 'like something' to see the color red, or to be aware of a particular thought, or any other mental percept that we are directly conscious of.

    I understand your reasoning in this regard, I'm just not so sure it can be so easily generalized as we go down the scale of biological complexity, especially if we go all the way down to the level of a bacterium. Plus, what of the example where one seems to be doing nothing but driving, but is still actually quite 'dim' since the process is still more or less 'automatic'?
  20. Oct 3, 2003 #19


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Here are some resources going into more detail about the neurobiology of blindsight.

    http://serendip.brynmawr.edu/bb/neuro/neuro00/web3/Chivers.html :

    http://sorrel.humboldt.edu/~morgan/blind_2.htm :

    http://www.fortunecity.com/emachines/e11/86/enm9.html :

    Furthermore, http://colour.derby.ac.uk/colour/people/westland/cfls3.html discusses patients with blindsight and split-brain patients in completely different contexts.

    From all this I think we can sum up by saying:
    1) Blindsight can occur in variable portions of the visual field, from very small to very large, depending on the nature of the brain damage.
    2) There is a mapping between areas of neurons in the primary visual cortex and areas of the subjective visual field. The blinded portions of the visual field in blindsight occur as a result of damage suffered by the corresponding neurons in the primary visual cortex.
    3) Something of the flavor of blindsight can occur in split-brain patients, but blindsight itself is not strictly a result of information being cut off from the left hemisphere of the brain.

    As such, I think my initial point stands-- blindsight is a demonstration of intelligent looking behavior without underlying conscious perception of the objects with which the blindsighted person intelligently interacts.
    Last edited: Oct 3, 2003
  21. Oct 3, 2003 #20


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I missed the point of what blind sight has to do with conciousness.. maybe someone can give me a quick hint?

    Isn't conciousness the act of NOT acting out of impuls? The lion story would go AGAINST conciousness. Conciousness is the ability to abstractly evaluate situations and act on it.

    I am not sure eather what the mirror experiment truly has to do with conciousness, more with image perception and brain processing/visualization. A dog knows a dog by its smell, not by some abstract pattern in silver, doesn't mean they are not concious.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Discussion on consciousness
  1. Brain consciousness (Replies: 22)

  2. Quantum consciousness (Replies: 10)