Giulio Tononi on Consciousness and Phi

what is consciousness and where does it come from this is rather open to debate the neuroscientist and psychiatrist Ryota Noli is one of the leaders in this elusive field here just before his lecture on the nwg but we met him right after he flew in from New York thank you for being here professor Tony you you work on consciousness for how many years now it's embarrassing to say let's just say that I decided to work on consciousness one way or the other when I was 16 well came time has elapsed in then but of course most of the time I haven't been able to do as much as I would have liked to unconsciousness so you can cut down as many years as you want in this cut down years have you found an easy answer to the question what is consciousness a short one there is always a short one that I give when I have to give a lecture and that is it is what goes away when you fall into dreamless sleep and the important thing about that is everybody knows what that means and well cut away seems to be literally everything you don't see anything you don't hear anything you don't feel anything you don't have any emotion or any thoughts it's all gone so as far as you're concerned there's nothing at all then of course you come back to consciousness which can be because you wake up or it can be because you have a dream so the shortest way of putting it is consciousness is experience any experience you might have sight and sound thoughts and feelings doesn't matter what any experience and the opposite is nothing at all okay so it is everything and when it's gone there's nothing yes as far as you are concerned you suspect that there will be still thing going on when you're gone but when you're gone as far as you're concerned is absolutely nothing um which means consciousness is basically everything as far as you're concerned so rather big a rather important might be true yes but it is subjective I know I got mine you could be a zombie and I would never know so how do you scientific research on something that's subjective well there it is subjective he's indeed one of the essential properties of consciousness Chalmers is certainly right in saying so and you knew it very well your consciousness is yours and it's not mine and this leads to this so-called zombie argument the idea that you cannot even prove for certain so far that your interlocutor me in this case is not just a machine but is seeing things and hearing things and not just acting as if he did okay so yes the subjectivity is true and normally scientists think oh well if it is subjective this is really outside of the realm of science quite the opposite I think you have to look at what is essential in consciousness subjectivity being one essential property once you list the essential properties then maybe it is possible to formulate a good hypothesis about what it takes for a physical system or let's say the ordinary kind to be able to support it so I see subjectivity as something that needs to be explained as opposed to an unsurmountable problem what else is near that what other path does does met puzzle of consciousness need a very simple way of putting it is that it has consciousness five essential properties and those are in addition to the fact which is not a property of existing and that was recognized long ago by the cart and others where consciousness exists and there is no way you can deny that it's in too beautiful it's immediate and of course it's inconceivable to think of an experience that you would have that would not exist so that's a good starting point culturally exist but what integrating information theory does IITs tetraman going to use for an abbreviation well IIT does is say that's not all there is to it which is essential and therefore is a good starting point for a scientific theory the other five are that it is subjective or intrinsic as we put it it's yours from your point of view not somebody else's that's also immediate it's also indubitable and it's possible true of every conceivable experience you cannot think of an experience of yours that could not be yours then there are others the one is that it is structured it always has parts that are related to each other in various ways you see the left you see the right but you see them together into a scene you hear my voice you see my lips you see them together and so on you see my jacket you see its color you see them together so many many many distinctions within each experience bound together in various ways as for this destructiveness of consciousness or composition information is that every experiences the particular way it is the one you're having now which presumably you never had exactly like this before well there is something that makes it what it is and different from unthinkable number of others that are different and that's a key property if you cannot have an experience that is generic you're going to have this experience okay these are all seemingly trivial because they are so basic you don't really pay much attention finally - I'd be very quick one is the consciousness is unified this has been remarked by many including cont for instance the fact that you've experienced what you experience always is one thing yes you may hear and see things and they may seem a little bit separated you know people talk about Metallica's but they are still seen and heard together there is sort of a center to which they both belong it's very different to see something and then independently hear something if you know that you saw and heard the Thunder and the lightning well that was a joint experience so it's unified and always because you don't see the left and the right of the visual field separate it's the field and the final property that I think is a foundational property of experience is called being definite it's the so-called axiom of exclusion being definite means that your experience contains what it contains not less not more so for instance right now you experience contains presumably my face my voice some colors etc it doesn't contain half of it say half of my face or just above my neck mm-hmm or me without color and so on and so forth it doesn't contain more it doesn't extend behind your back to include the entire room so again you can see why it is in a way trivial of course it's like that yeah completely used to that but it is an essential property it's inconceivable to have an experience that is not definite meaning it doesn't have borders with what's in and what's out and of course there must be a reason and that's where we get into now science for experience to have borders why does have borders why doesn't it just extend smear out into the universe why those borders why does it have to be unified why doesn't it break down into various pieces why is it that particular way why is it structure in that particular way why is it subjective of course you can also ask why does it exist at all let's leave that aside so this is the starting point this is the explained anthem what needs to be explained is the fact that it exists and these essential properties later we might explain its accidental properties why does your face look the particular way does to me okay the particular tone of coal or etcetera but those are accidental not every experience has to be of that color and this is true for most other things okay in fact I insist it's true also for space and time and invariance meaning the ideal faces we might be creature that don't have and thing about faces instead about some some others nowt or mouth I would say in German and so on and so forth and yet it would be an experience but the fundamental properties always have to be satisfied that's at least the idea of here okay you already named the theory integrated information theory it's got five explain anthems and where do they lead you to in this theory yes so this one really is constant it has five fundamental properties that characterize it and the thing to see is whether with these five of course we're just saying there is consciousness and it's a big mystery where it comes from and how could possibly come from IAT then does the second step which is the most you know cosplay step in terms of the time it took which are the translation of these fundamental properties of phenomenology of consciousness into fundamental properties of its physical substrate so we essentially postulate like everybody else that there is a world out there a world of physics which is the independent of me and it can be manipulated and observed the criterion for the physical to go very long time back in fact was formulated that time to play to more or less and I still think is the best has to do with being able to take a difference and make a difference if I can do this to your questions I actually manipulate something and I observe the changes and I can easily say what there's got something there you know here's some pieces of paper where you've written some questions and that is a simple-minded test for the physical in everyday life but you can go beyond everyday life into the most sophisticated science and search for the Higgs boson and the very same criteria applied just indirectly you are not going to convince somebody of the existence of explosions if you cannot show observable effects of some sort and if you cannot manipulate accelerator to produce the right energy level and so on and so forth so it's much more indirect but it still become is that something exists physically if it can I put it take a difference and do something to it and make a difference it could do something to you as small as that might be so that's the criterion for the physical engine and so IIT wants to translate the essential property of consciousness those five into essential properties that any physical substrate must satisfy if it can be as substrate for consciousness and it turns out that that is actually extremely constraining it's not that everything will do okay you have to actually have physical system of very very specific properties to be able to account for consciousness although it can be greater can be little constant as high consciousness so the work has been this translation into what online now called postulates which are the same they have to do with intrinsic oddity composition or being structural being specific being unified and being definite which we can express in physical terms so operations observations and they get given a mathematical form so that in principle we can literally go and look at different physical systems and say well how well is the system doing respect to these five properties in other word can it in principle be a substrate for consciousness consciousness is primary you start from your own consciousness and we make up a story about the existence of a physical world it's a very good story there is very good evidence for it by while the evidence for your consciousness is absolute indubitable the evidence for the way the physical world is is good but not absolute you start from there you start from conscious this is the starting point of science there will be no science without conscious behave ok but then of course there is plenty of good evidence about a particular model of the world in terms of things that take and make a difference and how they interact that explain lots of things has given us a lot of power but at the same time now the hard problem of fitting our own view to our own existence s conscious being that's the only existence that matters within the successful framework scientific framework of the physical world where we see that things like brains they seem to be especially important and but that wasn't so clear a long time ago it's become clear on over the past let's say five hundred years has been really clear and now we are still very primitive in terms of where within the brain because it looks like it's not the entire brain some parts of the brain we can take out and you know you may have problems nobody not not in your consciousness okay and other parts of the brain and more controversial does it really matter of consciousness or not and here we are still very much in a you know primitive state of affairs mm-hmm is in principle in principle would allow you to take anything but it's a brain or a liver or a computer as matter that is physically constituted is a physical substrate potentially apply these measures that translate the axioms of IET the essential properties of a phenomenal kind into essential properties translated into the physical and see well is it there is it not there how much and Oh which kind also the quality of consciousness is critical why does it feel like this say space and color and time and so on and not some other way that also has to be explained by a theory of consciousness now I said in principle because in practice is incredibly hard meaning then calculations are immense so we need to make many approximations and then the actual tools to get at the right level because you could do this at the level of neurons for instance in the brain but also at the level of molecules or atoms where you could pull to the level of macro units like groups of neurons at different time scales and all of these levels will tell you something about the physical interaction between that system but according to 80 there is the right 11 and that has to be found on first principles so it's practically very complicated to do it right I can't just take an instrument and just measure your consciousness like that I wish I could what we can do is inform guesses and very crude approximation that we have started already applying in the clinic so you work with patients those are this is one group you you try to measure yes we work with ourselves primarily so a lot of work with healthy subjects then we work with patients or with manipulations of consciousness like anesthesia in which we can produce at least big changes in consciousness what sort of everybody more or less agreed is happening this I was conscious then the doctor gave me this propofol injection and I was gone consciousness was gone so this is big and we must see a big difference in some of these measures that we think index consciousness sleep is another good case in point early in sleep you're sort of vanish hmm and then later you tend to come back in the form of a dream so we have interesting changes between being conscious not really being conscious again although you are disconnected from the environment and so under these conditions since this is us and we are still you know the best place were to try and validate the theory there we have tried to do many experiments to see whether some measures of integrated information do art we behave as pricked it they should be high when you're conscious and they should collapse when you lose consciousness okay in these very basic cases and this so far has succeeded really well in fact it's always succeeded better than anything we have right now the very first study was done on ourselves literally and then other healthy subjects using transcranial magnetic stimulation and high-density eg this is just a tool and we have to develop the tool to be able to sort of knock on the brain and see how it will respond the idea being that if it responds in a complex manner and yet there's one integrated system this sort of fulfills some of the basic basic requirements were integrating information theory it's both unified and informative differentiated it's very crude but at least it gives you an indication and it's causing because you are perturbing the brain so we did that and if I do this in you when you're awake and then when you are in early non REM sleep during the night in which your brain still active almost just as much yet somehow he lose consciousness we found that the response became much less complex so much less you know compatible with lo 5 which is sort of the measure of integrating information that we use when you lose consciousness so that fit the prediction and then we did it with many subjects then we started doing anesthesia of different kinds then we did Dreaming which is on the surface you are just asleep as before when you had no consciousness but now sometimes you do regain consciousness in fact it can be a very beautiful and strange dream where you have experiences so by definition you're conscious not of the environment but you're conscious and they're the measure was supposed to go back up and it did regularly so that's an interesting task because the state was subject is not really changing you mean still asleep in the same stage asleep sometimes she dreams sometimes he doesn't so it was a good test the measure should be high and low not depending on you know the overall state of the brain but whether you're conscious or not and it did so with anesthetic same story when you lost consciousness quite obviously the measure went down but with one anesthetic in particular which is ketamine that is rarely used alone but still sometimes in children certainly in large animals but we did it on healthy volunteers they lose responsiveness meaning they are mister sized and you could do surgery on them when they come out unlike the other anesthetics they regularly report that appropriate doses incredibly vivid and long dreams having nothing to do with the hospital where they were treated okay and so this is well known and we confirm this by asking them right afterwards and this index jumped back up like it does when you dream or when you are conscious during the day so there are some counterintuitive aspects okay if you paid it on behavior if you build on responsiveness you would throw the opposite conclusion you need something that evaluates the state of the brain with respect to consciousness according to a theory not just according to you know while he's not moving therefore okay and then the rest was really applied to patients were more difficult to understand so one we had a very good validation in us and with these different manipulations we were able to show that the value of this index which is called perturbation or complexity index and was developed by a colleague of mine in Milan was really above this value you are conscious humble and look below this value or not and then we can use that to go through the bedside or patients with a vegetative state which is now called you know unresponsive way for us in terms sometimes or with so-called minimally conscious state where it's difficult but some good neurologists can say I suspect there is somebody home so to speak and essentially the index did very well so it clearly says that the memory conscious patients identified the good good neurologists are high in this quantity so high consciousness sort of like you and me from what we can tell even if this crude and instead the vegetative patients typically know but even there other words are surprised so to speak you have like three levels 0 and then century we believe there is no functioning or system that can support conscious of any sort values which are the one you normally find in a deeply sleeping healthy subject or under anesthesia so they are long they are not appropriate for consciousness but they suggest something is going on that maybe with some interventions you may make them jump over the threshold like waking somebody up and then a fracture on 20 25 % with values like you and me and they don't respond at all so from the outside you couldn't tell from the MRI you don't know read what's going on it's very it's very unclear from the MRI how things are and from this index it will suggest that is somebody there and we should try to establish communication maybe through brain machine interface had we known playing tennis something like that yeah the plain tennis paradigm of hadrian horn was really the first sort of elegant demonstration using fMRI that in some of these seemingly vegetative patients you could establish communication but instead of having them you say yes or no they would counter in their mind a scene for instance playing tennis or going through the room that lead to very clear signature usually in normal subjects and those signature were seen also in that patient she had prefer the same thing so because it was a response to command it was just you know locked in it was made explicit on in terms of brain activity patterns there was a case that it would be very hard although some people tried to refute the conclusion that she's there she's just not able or willing to move but she can do that in her mind ok these cases are few and far between it's very hard because you may be conscious and incapable even know if people are conscious and can't do that because you need to sustain attention for a while instead the PCI index would certainly identify such cases but it doesn't require any effort on the part of the patients we're just probing the brain sort of like an electrician yep inserting a pulse of current we see the reverberation of the current and depending on that we say there is consciousness ok so he can work in a much larger proportion of patients they may be confused and may be tired and may be incapable of sustaining attention then they would fail the playing tennis test but they wouldn't fail the TMS eg last time I talked to your colleague fists of he came up and was wondering about that with quantum physics again I thought this was an explanation back from the 70s but it seems to be coming back do you think it there is some quantum physics aspect in consciousness or how do we just explain the unexplainable why are something else unexplainable well there are inevitable some quantum physics has been in consciousness because of the way our brain is constituted and there is an interesting twist now in science over the past few years which suggests that there may be some quantum level phenomenon happening at the temperature of the brain which is was hard to believe before but there may be some events but the fact there may be some events of some meaning even at sort of room temperature or body temperature doesn't mean that they play an important role okay there is a lot of quantum level activity happening in our liver and yet doesn't seem to be very important for consciousness okay so we have to keep something in mind I mean four quarters and unfortunately what happens is that because it has been christened as the heart problem and the century most people assume that it will never be solved it cannot be solved it goes beyond the realm of science or you name it or in the best case scenario you just wait for science to run its course amass more and more data and then perhaps one day we understand okay yes there is a freedom to come up with any notion and you can explain the unexplainable by the unexplained and so on and so forth do all of those things which are essentially I think a syndrome of failure of imaginations we we don't really think is doable consciousness looks like a transparent impenetrable wall and you don't see any attack point and then there are very understandable psychological reactions like you denied there is a wall you turn your back and go in the other direction or you say the wall is a quantum wall or who knows what else in order to essentially justify you in a bit each to even think how the problem could be grasped and attacked like a climber who sees an absolutely no place to put her hands okay you invent some excuse or some sort instead otherwise I wouldn't be working on integrating information theory I believe that you have to take this perspective from the inside that is you have to say what is true of my consciousness will I it's essential properties translate them to physical terms and once you do it which is not an easy process but can be done you can actually test the predictions with the theory for instance you can check whether this particular piece of biological organization let's say the brain and this particular part of the brain and within that this particular part does it have there were with all to support this very high value of I which is presumed for us okay and does it do in a way that accounts for the particular way our experience feels like first as we feel special you feel temporarily extended it feels colored or all the other phenomenal properties so this is a doable exercise in fact we are doing it we are beginning to do it it requires lots of computational resources but it's absolutely not something that you need to invoke mysterious new things to do you just need to understand better what it takes for something to exist from its own perspective in a structured specific unified and definite manner and then you'll be surprised so in fact the reason I'm optimistic is because even if our tools are crude and our understanding still of course were limited the theory can predict what could be and what could not be a substrate of high consciousness and for instance about our own brain it can predict rather clearly and then explain why say the cortex in general seems to be in a very good position to have high consciousness by other part of the brain a standard example is the cerebellum which is back here and he has five times more neurons than the cortex but it's also connected to inputs of all sorts it has maps and it's connected to cortex a lot so why does that piece of brain not contribute at all to motor experience but it contributes to regulating your gauge and so on and so forth you can cut it all out and nothing happens to your consciousness essentially we have several cases of this so that's an you know it's a challenge it says well it's his brain like as you want it's complicated as you want if there is something important being complicated which is not clear and it's connected intensely to cortex so why would my consciousness to speak end in cortex and not extend into this fantastic tool of neurons as the Serban but it doesn't so you need to explain that I think we explain that quite properly and I think one of the most intriguing parts that we are working on right now is even within cortex there is evidence that some parts are important for consciousness some parts aren't now there's also great ignorance and great controversies or people let's say are not so sure about which parts in fact some people may think that all cortex somehow must matter okay just because I think but I think the experimental evidence if you look at it objectively is pointing Daphney in certain directions but Pete as it may IIT has an interesting position their IT say is whatever the subset of conscience is it must satisfy these five essential properties in physical terms so the short version is it must be a global maximum of intrinsic cause effect power that's just another way to say all these properties intrinsic ality being structural being specific being unified and being definite they must be selves satisfy but as physical substrate once you know how to do it to check what it does and so we should look for that in our cerebral cortex my guess is we are going to find that there is a maximum and this maximum is not going to be the entire cortex and it's not going to be probably most of the prefrontal cortex for instance which people take us of the most evolved and sophisticated of all our organs in the brain it's going to be primarily in posterior regions in the back of the cortex where the sensory input comes in and the body input comes in visual notation exception which is organized in a way much more simply it's like grids stacked upon grids with little hierarchies and so on and so forth that part we think has the prerequisites to be really - and to be a maximum so now the theory essentially is making a very strong prediction it says if we find a maximum with all due respect of the methodological tools we have of course effects power which is what the theory says independent of what it is made of is it neurons is it transistors is it groups of neurons is it doesn't matter wherever there is a maximum of that there should be consciousness and this can be tested first and foremost in us if that maximum turns out to be in the same areas of the brain say cortex where the empirical evidence suggests that if I kill those you lose consciousness if I take one of one of those you lose a piece of conscience so to speak the ability to see faces and so on and so forth if that fits it's good for the theory if it turns out that you do something to this maximum of five and nothing really happens to conscious but you do it somewhere else and something big happens the caution the theory is dead okay so this is an area which is delicate in the sense of you know the tools or never idea fMRI has temporal resolution which is non-ideal spatial resolution is okay but not that great yet and so on but still they can give us a sense so I think the predictive and testing the prediction side of the theory is become much much more precise and for that reason intrigued it sounds wonderfully down-to-earth and it sounds like you might solve a problem that we are about to face which is when do computers become conscious so you will be able to measure it while five yes and I'm actually very passionate about this I've considered this to be an urgent matter and this is because you can show in IHC and we have shown the main paper is is coming out soon that no matter how sophisticated one of our computers is right now the one that are able to drive cars the one that I booked to have a conversation the ones that I able to translate a conversation and solve mathematical problems and all kind of other problems they are not yet as good as we are in everything but they are getting better and better but but if their physical substrate is that of a computer which it is IIT says that they have literally zero consciousness they will be able in principle to do all the things we do talk as intelligently or unintelligently as you and I do convince you that you won't have dinner with me now because he has described interesting and yet there will be absolutely nobody there NIT is unique in this it doesn't say computers are not because they are cold they are machine they don't have a motion on our computers can simulate anything they're not there yet but they will and when they do that we will not be able to tell them apart from other human being except for perhaps for saying the nicer they behave better and they are vastly educated and so on and so forth but if IIT is right there is really a complete divide there they would be functionally equivalent to us from the point of view of what you can do with them they are like us they would be phenomenally absolutely different from us they won't exist at all and this is obviously very very big ethical implications as you can imagine yes whether we as a society the end values you know what you you get things that do things very well or values being ultimately that you exist and you exist in the particular thing IIT makes that divide extremely sharp it's a pity we have to finish here because the bar is about to open thank you very much thank you [Music]

Channel: dasGehirnInfo

Views: 9,850

Rating: 4.890625 out of 5

Keywords: Bewusstsein, Consciousness, Guilio Tononi, Integrated Information Theory, IIT, Phi

Id: huxh9YCL5nM

Length: 35min 34sec (2134 seconds)

Published: Mon Apr 15 2019