A must read and a must see! Part 1/18 below, the rest on youtube.
Saturday, 12 March 2011
Wednesday, 9 March 2011
Book Review: Consciousness Explained (D. Dennett): part V : Delay of consciousness
In the 80's, Libet reported an experiment where subjects (wearing scalp electrodes) were asked to flex one hand at the wrist while noting the position of a moving spot at the precise time they formed the intention to flex. Afterwards, said subjects reported where the spot was at the moment they decided to flex their hand. The electrical measurements performed by the electrodes permited to determine that the subjects flexed their wrist 350 to 400 ms before the time indicated by the subject as being his time of intention to flex.
This experiment seems to indicate that we are conscious of the decisions made by our brain AFTER they have been made.
It seems to me that Dennett does not like this conclusion (although he does not express it explicitly) which seems to contradict the intuition that our conscious acts control our bodily motions.
He considers this kind of explanation as being stalinesque (i.e. presuming that the brain delays consciousness in order to be able to presents all the facts it wants to present in the order it wants them to be presented).
He points out that there is an alternative explanation: "the subjects were conscious of their intentions at an earlier moment, but this consciousness was wiped out of memory (or just revised) before they had a chance to recall it". He calls this kind of explanation "Orwellian" because history is re-writen after the facts.
Finally, he also points out that yet another explanation which is that "an element of content becomes conscious at some time t, not by entering some functionally defined and anatomically located system, but by changing state right where it is: by acquiring some property or by having the intensity of one of its properties boosted above some threshold."
Dennett seems to doubt very much the possibility to equal the time of reporting of the subject with the time of conscious experience.
Personally, I would call on Ockham's razor with such an issue: stick to the simplest hypothesis until proven otherwise. Hence, as far as I am concerned, this experiment seems to indicate that consciousness arises after the facts. Clinical cases like the case of Mrs. Dee in "sight unseen" are also pointing toward such an explanation.
I think Dennett doubly dislikes the results of this experiment. 1) as mentioned earlier, it places consciousness after the events and 2) it looks like we are watching a movie of our live in a cartesian theater (he despises the idea of the cartesian theater).
[this page has been amended on 12/03 after a reader pointed to me some errors of interpretation. Thanks to Jason]
Tuesday, 8 March 2011
My own opinion on "consciousness"
Consciousness and memory
I will try to explain what is my vision of what I think consciousness might encompass. I am sure I do not understand fully what consciousness is (otherwise I would not be reading and thinking so much about it). I however partly developed and partly stole ideas that, put together, gives me a hypothesis of what consciousness could be.
It all started I think in 2007 when I was driving back from a patent law course in Antwerp. It was dark, there was nothing on the radio and I thought "you have no opinion whatsoever on what consciousness could be. Why don't you try to make yourself one by developing it from first principles?"
And so I started to think about what was necessary for experiencing consciously something? I started to reason: "if I hear something (e.g. a word) I can be conscious of it. Why?" How do I know that I heard it? Answer:"because it is in my memory and I can retrieve it. If it was not there, I would not know I heard it".
Then I thought "OK! So what happens exactly when I hear a word, e.g. the word 'abracadabra'?"
I thought that I first hear each sound of the word and that my brain "recognises" it. So I first hear the beginning of a "a", then the end of a "a" then the beginning of a "b" and so on.
But what would happen if I did not have a good memory? I might forget the beginning of the word at the time I am hearing the end of the word and this word would not make sense to me but I would nevertheless be conscious. However if you ask me 10 seconds after having telling me the word "abracadabra" whether I heard it (actually I would not even understand your question and I would not be able to answer it... but let say for the sake of this thought experiment that my memorisation capacity was brought back to normal before you asked me this question), I would answer "no" since I would have forgotten this word already.
Now let's decrease my memory even further to a time span of let say one millisecond. I would hear the beginning of a "a", then forget it, than I would here the middle of the "a", then forget it, then I would hear the end of a "a", then forget it. I would have some kind of rolling consciousness with a very short time span. This would be so far from what we experience as human conscious beings that we can hardly still call that a conscious state.
What would we experience if our short time memory had a time span infinitesimally short? Or no memory at all? I claim that this would equal to not being conscious.
From this thought experiment, I concluded that without memory, no consciousness.
Puropose or cause of consciousness
I then proceeded to think "aha! Memory is necessary for consciousness. Could it be that consciousness evolved together or after memory? Could it be that consciousness serves a purpose linked to memory or that being conscious is what it feels like to memorise?".
I then realised that we can be more or less conscious. We can be very aware of something or almost not aware at all of this thing. For instance, I was driving since half an hour but I was only barely conscious of the road. At other times I am very conscious of the road. So what could be the purpose of something varying in intensity and potentially serving memory?
I thought BINGO! Consciousness with its varying levels of intensity could serve as labels! Consciousness of something with a particular level of intensity could be a "label" informing the memorisation processes of the brain on the importance of said thing. It could also be the other way around. Maybe we just experience stronger consciousness feeling for stronger memories.
For instance, you see a free lion in front of you: you will be VERY conscious of its presence and your brain will record very deeply (and forever) this information instantaneously in your long term memory.
Another example: you see a small stone on the road. Your eyes saw it. This information entered your short term memory but you will not be very conscious of it at all. As a result, your memorisation processes having received the "low consciousness" label associated with this stone, you will quickly forget it and you will never ever be able to recall it.
Actually, we are at any given time bombarded with thousands of inputs, both internal and external. Our senses are incessantly receiving information. If we had to memorise all of them vividly and for ever, our memory would be full in no time. We therefore need to rank information by order of importance, in other words: we need a filter. This filter might or might not be consciousness.
This information is important for our survival (e.g. uncaged lion) or our reproduction (e.g. sexy lady/man)? Our brain attaches the label "very conscious" to it and it gets written deep into our memory.
Is this information unimportant (e.g. one tic of a clock amongst many)? Our brain attaches the label "barely conscious" to it and this information will quickly be forgotten.
Actually, we could very easily replace the word "consciousness" by the word "attention" in the last part of my analysis above.
Also, I could make sense of the same insights by making the alternative hypothesis that a label (or filter) (which is not "consciousness" but well "attention") is attached to each input and what we "feel", i.e. what we are "conscious" of is the process of memorisation. When something is memorised, we are conscious of it. When it is deeply memorised, we feel deeply conscious of it.
Another facet of what I think consciousness is comes from experiments in experimental psychology which all tend to indicate that our brain already knows we will move our wrist before that we are ourselves aware that we will move our wrist (Libet et al, 1983). I think this kind of experimental results fit nicely with my vision above because when your arm moves, it is best for you to keep in memory that it did! As a result, this information is engraved in your memory and you are simultaneously conscious of it.
You are conscious of many things your body experience but you are feeling it "after the facts".
This vision of consciousness is also compatible with my vision of free will (there is no free will).
We are spectators of our own lives. Just like when we go to the movie: sometimes we really think we are living it. Well, we also really think that we are in charge of ourselves...but we are not. The illusion is however almost perfect. This illusion falls apart e.g. when lesion to the primary visual cortex occurs.
Imagine that in the future we would be able to watch a movie while simultaneously feeling and thinking absolutely all what the actor feels and think. We would very easily be convinced that WE are the actor and that the actor that WE are has free will.
Later I would like to make a post on these psychological experiments I referred to. I also would like to speak about split brains, phantom limbs, rubber hands, and Mrs. Dee (a woman whose brain has been damaged and whose case is detailed in the book "sight unseen").
I will try to explain what is my vision of what I think consciousness might encompass. I am sure I do not understand fully what consciousness is (otherwise I would not be reading and thinking so much about it). I however partly developed and partly stole ideas that, put together, gives me a hypothesis of what consciousness could be.
It all started I think in 2007 when I was driving back from a patent law course in Antwerp. It was dark, there was nothing on the radio and I thought "you have no opinion whatsoever on what consciousness could be. Why don't you try to make yourself one by developing it from first principles?"
And so I started to think about what was necessary for experiencing consciously something? I started to reason: "if I hear something (e.g. a word) I can be conscious of it. Why?" How do I know that I heard it? Answer:"because it is in my memory and I can retrieve it. If it was not there, I would not know I heard it".
Then I thought "OK! So what happens exactly when I hear a word, e.g. the word 'abracadabra'?"
I thought that I first hear each sound of the word and that my brain "recognises" it. So I first hear the beginning of a "a", then the end of a "a" then the beginning of a "b" and so on.
But what would happen if I did not have a good memory? I might forget the beginning of the word at the time I am hearing the end of the word and this word would not make sense to me but I would nevertheless be conscious. However if you ask me 10 seconds after having telling me the word "abracadabra" whether I heard it (actually I would not even understand your question and I would not be able to answer it... but let say for the sake of this thought experiment that my memorisation capacity was brought back to normal before you asked me this question), I would answer "no" since I would have forgotten this word already.
Now let's decrease my memory even further to a time span of let say one millisecond. I would hear the beginning of a "a", then forget it, than I would here the middle of the "a", then forget it, then I would hear the end of a "a", then forget it. I would have some kind of rolling consciousness with a very short time span. This would be so far from what we experience as human conscious beings that we can hardly still call that a conscious state.
What would we experience if our short time memory had a time span infinitesimally short? Or no memory at all? I claim that this would equal to not being conscious.
From this thought experiment, I concluded that without memory, no consciousness.
Puropose or cause of consciousness
I then proceeded to think "aha! Memory is necessary for consciousness. Could it be that consciousness evolved together or after memory? Could it be that consciousness serves a purpose linked to memory or that being conscious is what it feels like to memorise?".
I then realised that we can be more or less conscious. We can be very aware of something or almost not aware at all of this thing. For instance, I was driving since half an hour but I was only barely conscious of the road. At other times I am very conscious of the road. So what could be the purpose of something varying in intensity and potentially serving memory?
I thought BINGO! Consciousness with its varying levels of intensity could serve as labels! Consciousness of something with a particular level of intensity could be a "label" informing the memorisation processes of the brain on the importance of said thing. It could also be the other way around. Maybe we just experience stronger consciousness feeling for stronger memories.
For instance, you see a free lion in front of you: you will be VERY conscious of its presence and your brain will record very deeply (and forever) this information instantaneously in your long term memory.
Another example: you see a small stone on the road. Your eyes saw it. This information entered your short term memory but you will not be very conscious of it at all. As a result, your memorisation processes having received the "low consciousness" label associated with this stone, you will quickly forget it and you will never ever be able to recall it.
Actually, we are at any given time bombarded with thousands of inputs, both internal and external. Our senses are incessantly receiving information. If we had to memorise all of them vividly and for ever, our memory would be full in no time. We therefore need to rank information by order of importance, in other words: we need a filter. This filter might or might not be consciousness.
This information is important for our survival (e.g. uncaged lion) or our reproduction (e.g. sexy lady/man)? Our brain attaches the label "very conscious" to it and it gets written deep into our memory.
Is this information unimportant (e.g. one tic of a clock amongst many)? Our brain attaches the label "barely conscious" to it and this information will quickly be forgotten.
Actually, we could very easily replace the word "consciousness" by the word "attention" in the last part of my analysis above.
Also, I could make sense of the same insights by making the alternative hypothesis that a label (or filter) (which is not "consciousness" but well "attention") is attached to each input and what we "feel", i.e. what we are "conscious" of is the process of memorisation. When something is memorised, we are conscious of it. When it is deeply memorised, we feel deeply conscious of it.
Another facet of what I think consciousness is comes from experiments in experimental psychology which all tend to indicate that our brain already knows we will move our wrist before that we are ourselves aware that we will move our wrist (Libet et al, 1983). I think this kind of experimental results fit nicely with my vision above because when your arm moves, it is best for you to keep in memory that it did! As a result, this information is engraved in your memory and you are simultaneously conscious of it.
You are conscious of many things your body experience but you are feeling it "after the facts".
This vision of consciousness is also compatible with my vision of free will (there is no free will).
We are spectators of our own lives. Just like when we go to the movie: sometimes we really think we are living it. Well, we also really think that we are in charge of ourselves...but we are not. The illusion is however almost perfect. This illusion falls apart e.g. when lesion to the primary visual cortex occurs.
Imagine that in the future we would be able to watch a movie while simultaneously feeling and thinking absolutely all what the actor feels and think. We would very easily be convinced that WE are the actor and that the actor that WE are has free will.
Later I would like to make a post on these psychological experiments I referred to. I also would like to speak about split brains, phantom limbs, rubber hands, and Mrs. Dee (a woman whose brain has been damaged and whose case is detailed in the book "sight unseen").
A universe from nothing (Krauss)
Excellent talk about how the universe could have originate from nothing, what we mean by multiverses, and so on...
Monday, 7 March 2011
Saturday, 5 March 2011
Book Review: Consciousness Explained (Daniel C. Dennett): part IV (his model of consciousness)
The main purpose of Dennett's book is to 1) refute the carthesian theater model of consciousness (see image below), and 2) introduce his own new model instead. He calls his new model the multiple drafts model.
The Cartesian Theater:
A representation of the carthesian theater model of consciousness is depicted below:
In this picture, we can see the head of a man looking at an egg being fried in a frying pan. Inside this man's brain, a screen is present where the vision of the man is projected for a smaller man to look at. The smaller man (or homonculus) is a methaphor for a central part in the brain where "consciousness happen".
The carthesian theater model assumes that their is a central "organ" in the brain where what happens is what you are conscious of. Its most naive form is the idea that a spectator must be present in the brain in order for the senses inputs to be experienced. Descarte for instance considered the pineal gland to be such a center from where the input of the senses could be transduced from mechanical signals (Descarte was not aware of the electrical nature of these signals) to spiritual meanings for the soul's benefit.
The Multiple Draft Model:
In this model, there is no centre where everything has to converge in order to be experienced. On the contrary, different conscious events are generated at different places in the brain. Each element within an event is discriminated only once. For instance, if you see a cow, the brain discriminate the presence of a large object, then it notice it is an animal, then that it is a cow. The discrimination and its fixation in the memory is enough for the phenomenum to be conscious (if probed).
What will be conscious will depend of the time of the probing. If you probe too early, you will only experience the diffuse presence of a large object. If you probe very late, you will have forgotten everything.
There is no need for the discriminated element to be sent or linked to a central theater. The conscious experience will originate from the locus of the discrimination. Also, each element is constantly updated/modified (e.g. interpreted, refined, partly erased, ...) due to interaction with the rest of the brain (pre-existing memories, new inputs, ...).
The multiple draft model makes"writing it down" in memory criterial for consciousness.
This can be best understood by looking at the color phi phenomenom at the bottom of this post (I do not insert it here because it is a moving image that would disturb your reading). To most people, the color phi phenomenom is experienced as a red spot traveling from left to right and changing color midway to become green. However (and you can easily convince yourself thereof by hiding one of both spots), it is in fact nothing of the sort. It is simply two fixed spots, one red and one green, the first blinking out of phase with respect to the second.
When experiencing the color phi phenomenom, the brain does not need to place intermediate spots after having experienced the second spot because there is no part of the brain present to "watch" these intermediate spots, your brain (i.e. you) just "knows" that the spot moved.
When remembering past events, you don't feel them happening again, you just know they happended. For instance, if you try to remember with as much details as possible the pain you experienced the last time you knocked your toes against an obstacle, you will not experience real pain, you will just realize that you "know" what kind of pain it was (which intensity, which location...).
His model makes a lot of sense but what remains unclear to me is the following:
At any given time our brain is processing a lot of inputs: external inputs from our various senses and internal inputs. We clearly do not feel conscious of them all. Cerrtainly, we do not feel conscious of many of them "simultaneously". Dennett seems however to say that whenever an object of our phenomenology is discriminated by our brain, it is "conscious".
On another hand he alludes to the notion of probing. Probing that would determine what is reported as conscious. He seems to make a difference between what is conscious and what we report as conscious experience when asked (i.e. probed) to report.
What I don't get is what he exactly means by his notion of "probing". I get it only partialy. I get it when by probing he means triggering a report from the conscious subject: e.g. asking the guy what he sees/feel. However, we are not constantly being asked to report on our internal states and we feel nevertheless conscious in these apparently "non-probed" times.
Of course, I suspect that his notion of what the probing is is more subtle than that. I suppose that internal inputs and external inputs can themeselves serve as "probes".
Maybe this notion is better explained in the rest of the book.
Once very important phrase he wrote is "The multiple draft model makes"writing it down" in memory criterial for consciousness".
I fully agree with the fact that writing something down in memory is critical for consciousness!
I have my own partial theory on consciousness and I should maybe explain it here before to continue Dennett's book. In view of the bold sentence above, I suspect that his views and mine overlap largly.
The Cartesian Theater:
A representation of the carthesian theater model of consciousness is depicted below:
In this picture, we can see the head of a man looking at an egg being fried in a frying pan. Inside this man's brain, a screen is present where the vision of the man is projected for a smaller man to look at. The smaller man (or homonculus) is a methaphor for a central part in the brain where "consciousness happen".
The carthesian theater model assumes that their is a central "organ" in the brain where what happens is what you are conscious of. Its most naive form is the idea that a spectator must be present in the brain in order for the senses inputs to be experienced. Descarte for instance considered the pineal gland to be such a center from where the input of the senses could be transduced from mechanical signals (Descarte was not aware of the electrical nature of these signals) to spiritual meanings for the soul's benefit.
The Multiple Draft Model:
In this model, there is no centre where everything has to converge in order to be experienced. On the contrary, different conscious events are generated at different places in the brain. Each element within an event is discriminated only once. For instance, if you see a cow, the brain discriminate the presence of a large object, then it notice it is an animal, then that it is a cow. The discrimination and its fixation in the memory is enough for the phenomenum to be conscious (if probed).
What will be conscious will depend of the time of the probing. If you probe too early, you will only experience the diffuse presence of a large object. If you probe very late, you will have forgotten everything.
There is no need for the discriminated element to be sent or linked to a central theater. The conscious experience will originate from the locus of the discrimination. Also, each element is constantly updated/modified (e.g. interpreted, refined, partly erased, ...) due to interaction with the rest of the brain (pre-existing memories, new inputs, ...).
The multiple draft model makes"writing it down" in memory criterial for consciousness.
This can be best understood by looking at the color phi phenomenom at the bottom of this post (I do not insert it here because it is a moving image that would disturb your reading). To most people, the color phi phenomenom is experienced as a red spot traveling from left to right and changing color midway to become green. However (and you can easily convince yourself thereof by hiding one of both spots), it is in fact nothing of the sort. It is simply two fixed spots, one red and one green, the first blinking out of phase with respect to the second.
When experiencing the color phi phenomenom, the brain does not need to place intermediate spots after having experienced the second spot because there is no part of the brain present to "watch" these intermediate spots, your brain (i.e. you) just "knows" that the spot moved.
When remembering past events, you don't feel them happening again, you just know they happended. For instance, if you try to remember with as much details as possible the pain you experienced the last time you knocked your toes against an obstacle, you will not experience real pain, you will just realize that you "know" what kind of pain it was (which intensity, which location...).
His model makes a lot of sense but what remains unclear to me is the following:
At any given time our brain is processing a lot of inputs: external inputs from our various senses and internal inputs. We clearly do not feel conscious of them all. Cerrtainly, we do not feel conscious of many of them "simultaneously". Dennett seems however to say that whenever an object of our phenomenology is discriminated by our brain, it is "conscious".
On another hand he alludes to the notion of probing. Probing that would determine what is reported as conscious. He seems to make a difference between what is conscious and what we report as conscious experience when asked (i.e. probed) to report.
What I don't get is what he exactly means by his notion of "probing". I get it only partialy. I get it when by probing he means triggering a report from the conscious subject: e.g. asking the guy what he sees/feel. However, we are not constantly being asked to report on our internal states and we feel nevertheless conscious in these apparently "non-probed" times.
Of course, I suspect that his notion of what the probing is is more subtle than that. I suppose that internal inputs and external inputs can themeselves serve as "probes".
Maybe this notion is better explained in the rest of the book.
Once very important phrase he wrote is "The multiple draft model makes"writing it down" in memory criterial for consciousness".
I fully agree with the fact that writing something down in memory is critical for consciousness!
I have my own partial theory on consciousness and I should maybe explain it here before to continue Dennett's book. In view of the bold sentence above, I suspect that his views and mine overlap largly.
Friday, 4 March 2011
Book Review: The Gnostic Gospels (E. Pagels)
Actually the title of this post should better read "Audiobook Review" because it is in this format that I "read" it. The book is about the secret live of Jesus and about the alternative forms of Christianity that were existing c.a. 50-150 A.D.
The author of the book is a historian. The content of the book is an analysis of the so called "Gnostic gospels".
You might know that the gospels of Matthew, Marc, Luke and John where not the only gospels written in the period 100-400 A.D. Several others gospels (e.g. Mary, Thomas, Truth, Philip, Judas) also date from this period. They are authentic documents that were discarded by the church when compiling the New Testament.
Here are a few differences between the canonical version of the New Testament and some of these Gnostic gospels:
- Jesus was not resuscitated in flesh but in spirit only,
- The god of the ancient testament is not the same as the god of the new testament: the god of the ancient testament is "the creator", a kind of artisan who wrongly wanted to believe that he was the only god. Actually he had a "mother", i.e. the ultimate cause of everything and "father/mother" of Jesus,
- The Orthodoxs are praying the "creator" while the Gnostics are praying his "mother",
- The Christian god was a woman or had both sexes intermingled within him/her,
and so on...
In a nutshell, the author indicates that there was a conflict between an orthodox Catholicism which was in a process of strengthening itself and which was quite dogmatic, and a Gnostic Christianity which was rejecting the authority of the bishops and was much more open to an evolving and therefore changing Christianity.
This book gave me a better idea of how the church became what it is and why it resists so much the ordination of women for instance (the Gnostics were in favor of woman preachers)...
For those who wonder: No, it did not convert me to anything.
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