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Stewart Brand: Good evening Im Stewart Brand from the Long Now Foundation. Ive just been talking with our speaker tonight. One of the peculiarities of archaeology he reminded me of is that we assume the past is the past and after we have done a century or two of archaeology we assume that our knowledge of the past is our knowledge of the past and thats that. It doesnt work that way. We have barely touched the past, we have done tiny amounts of digging in tiny amounts of places and then formed these huge speculations about what actually happened, what our story is actually made of. And because the instruments keep getting better, the theories are getting better, well hear some good ones tonight, there are more and more archaeologists out there digging, we keep retelling the story of how we got here and this is not going to stop. The history of humanity, interestingly enough, is, not only is our future work in progress, our past is a work in progress. Please welcome Sander van der Leeuw. Sander van der Leeuw: Well its a great pleasure to be here, I can't see any of you because the light is too strong but thats maybe a good idea, you will have to find your own reactions to this. What I like about the way Stewart just introduced me is that indeed one of the things I am going to try and do is give a different, very personal, reassessment of a couple of million years of human history up to a fairly recent present. I am clearly going to do that in very large steps and there are some underlying ideas that I will try and bring to the fore which I think have direct relevance for what is happening at present. This is where I am going to start and I am going to start here for two reasons, this is a series of three little slides that posits a problem that you all know very well and that has to do with sustainability and I am putting that in there because I think my own perspective as an archaeologist has given me a very different sense of what sustainability is all about than what a lot of people have. I have come to that topic because as an archaeologist I was asked in the early 90s by the European Union to do a project on modern land use problems and the relationship in particular between towns and rural communities and I did that for ten years with a wonderful team of about sixty scientists from all over Europe which was basically having my own private university and organizing my own courses the way I would like them and to see what I could learn. So what I am presenting here is a mixture of ideas that come out of archaeology and ideas that come out of the study of the present and what I am going to try and do is bring all of this together. Its very much a work in progress and so there maybe moments where I do a hiccup of something like that but we will see how far I can get. These images speak more or less for themselves, on the left hand top side you see an evolution of US GDP and below it world wealth in deciles per continent and then on the top right a sense and the bottom right as well of where wealth is actually going in the present time and I am simply putting that as one of the main issues that we have to deal with. The result of that is this, this is a graph that many of you will have seen, it comes from Will Steffens work and it is basically a call to arms for the sustainability movement and it takes a very wide range because this is only two of the graphs that he has and basically shows the acceleration of the sustainability problems that are hitting us in every which direction, whether its the damming of rivers, climates, pollution of the earth, of the ocean and so on and so forth and very recently I have had the good fortune to participate in a paper that takes the whole sustainability issue out of climate change alone and basically argues that there are a number of other dimensions where the earth is just as much under threat of destabilizing itself due to our influence and some of those are mentioned on the right hand side. Well that to me is the backdrop and I will only come back to that at the end of my talk when I am talking about maybe ways in which we could do something about this. But lets look at archaeology for a moment and look at what is your favorite topic: the long term. There is a number of reasons from my perspective to actually look at very long term dynamics and this comes out of the work I did in Southern Europe. If you dont, as most of us dont, you miss a whole package of dynamics that are ultimately of great importance. Moreover, what you dont do is to observe complete cycles of change, if you have the models that now drive our economies whether its the World Bank or the government or somebody else, we basically look back for about a hundred years, maybe two hundred years to numerical data and we observe a very narrow part of the total system behaviors that could have happened and more than that we actually observe a highly biased part that is biased towards all the things that have been going on recently. But to me more important than anything else as an archaeologist is that we forget to observe the change of change, we dont observe how processes themselves change and in my own work over the last twenty years that has in many ways become the most important lesson of long term thinking. Archaeology does this and as Stewart just said it does it very, in a very fragmented way, it has a lot of trouble doing it but it has also a couple of major advantages. Most of the climate data is data that doesnt take any humans or animals or plants very much into consideration because it is polar data and it goes through the gas phase of the atmosphere. There are very rare sites and one of those we are currently and when I say we it is people in my department are currently digging on the south coast of South Africa where we have three hundred thousand years in one cave and so loosely packed that we can actually begin to distinguish different very short periods. Stewart was referring to new techniques one of the more amazing techniques that is now possible is we can actually approximately date single sand grains and that is helping us with these kinds of things. So what can archaeology contribute, it can contribute an evolution of the terrestrial environment over the very long term time that takes humans into account but also animals, plants and everything else. It can also help us with understanding the evolution of human behavior and that is a lot of this talk is going to be about and then finally it allows us to downscale from global to regional and that is one of the biggest problems that the sustainability science right now is coming as it does out of climate science which is essentially global and we have a lot of work to do to convince people and IPCC is doing that for example, to convince people to actually start looking at the regional scale because in the end the adaptations have to be done at the regional scale, they can't be done at the global scale. Now the archaeological record is the only one in my mind that can do these things partly because it is not a written history so it has not the bias of individuals, it is omnipresent all over the world and it integrates a very wide range of sources. On the other hand as Stewart said it is very difficult to interpret and our added problem is and he didnt say that, he left that to me to say and I will do it with quite a strong feeling about it, we destroy all the evidence that we dont already know. When we go out into the field we recognize things, those things that we recognize we preserve or we record, those things that we dont recognize we dont know about and we destroy them and so we have a very slow proof cycle in archaeology and because of that a lot of archaeological evidence and my talk will suffer from that in a major way, is actually based on getting the most coherent picture together rather than necessarily saying well this is the truth. That also for me personally is a great privilege because it allows me to roam much freer in my thinking about these things, than some of my colleagues can do but that is another story. Now these hockey stick curves as the ones that Will Steffen published, the ones that showed this very rapid acceleration, they pose us as archaeologists a couple of questions. On the one hand this covers the last couple of centuries, now why did it take us millions of years as a species to come to this particular point? And once we got there why did it then go so fast? And then finally, and I have left that for the last, what is it? We dont know. What I am going to try and defend here today is that it is not the climate or the environment but that it all hinges on the innovative capacity of society and so I am going to try and take you through the evolution of human cognition and innovation and outline a number of the crucial transformations that have happened over a long term time in the way humans interact with their environment. So the question there is what is different about humans that they can develop such complex technologies as we are currently doing and the first question that you then get when you think about humans who are both biological beings and social beings is what are the enabling factors, are they biological or are they essentially social-cultural? Now where I am going back to is a particular concept that is the short-term working memory, that is the sense that in our minds we can bring together, when we are thinking or doing, a limited set of informations that we can manipulate, transform, do all kinds of things to, but it is very, very limited. The difficulty of course for archaeologist is that this is very, very difficult to document because what do we have, we have skulls, we have skull sizes but we dont really have any ancient evidence on the evolution of that short-term working memory so I am going to have to approach that in two different ways. I am on the one hand going to compare in the way of direct evidence the size of the short-term working memory of primates and that of human beings and I am also going to follow on the next couple of slides a two lines of indirect argument that help us corroborate this particular part of the story which is the first part and the biological part of the story. What we know from many experiments whether its Frans de Waal or others observing them in captivity or in the wild we know that chimpanzees can crack nuts and that that involves essentially three objects an anvil, a nut and a hammer but we also know that there is only about seventy five percent of the chimpanzees that can actually learn to do this and the conclusion of the people who are doing this research in much more detail than I will ever be able to do is that that short-term working memory that they have is essentially two plus or minus one, that is, the best can indeed deal with three objects, can manipulate those in ways they want, but some of them can't and those have only two objects. There are a number of other tests and I dont want to go into those now that point in the same direction, ways in which you can combine tokens, the ways in which you can get them to manipulate objects to combine gestures and so on and so forth. Another line of research, argues that the short-term working memory of modern humans is actually a factor seven plus or minus two. Now lets look at the indirect evidence and this is also, by the way I should say, the human evidence is also based on experiments on the number of things that you can actually juggle at the same time. Lets look at the indirect evidence. What we know is that chimpanzees achieve that maximum short-term working memory at an age of two or three years old, between thirty six and forty eight months. We also know that humans when they are four or five can actually deal with three objects, everybody. What this graph shows is a projection over the first fourteen years of human existence of what that growth if we assume that it is linear will actually let us see that we then have at the age of about fourteen that working memory of seven plus or minus two so this is not a corroboration but it helps to understand a little bit what is going on, we have to make two assumptions. On the one hand that the development is linear through the beginnings of an animal or humans life and secondly that it actually stops with adolescence, the age of two or three is adolescence for a chimpanzee, for humans it is lets say thirteen or fourteen. So another way in which we can begin to look at that is to calculate the size of the brain relative to the size of the body and that is what is called the encephalization quotient that is what is the relative growth of the body, of the head respective to the actual body and that is what is being put on this particular graph. On the right hand side we look at essentially six and a half million years ago and we assume that chimpanzees at that time had essentially the same working memory and the same brain size as they do now and we have some skeletons to actually affirm that. When you move towards the left you actually move with time and you see these bars that are essentially illustrating where in time we actually for the first time have evidence of more than a factor two of manipulability in the various proto-humans and humans that we have the evolution of. The triangles and the blue dots and the two rectangle are different peoples evidence about when these particular subspecies actually are found and that is what we are now getting on to with the next slide because what I am going to do next, oh no one slide in between. So we have this evolution of what is essentially cognitive capacity. We see over that whole period a huge variability in climate, but we dont see any major changes in what people can do and I will show you that in a moment. So the question then is why is that so, why if climate change was so dramatic, cultural change was actually minimal over that whole long period and my argument there is that the signs of the short-term working memory actually for that period constrains the cognitive complexity of early artifacts and what I am going to do in the next few slides is show you how we can begin to trace, how proto-humans and early humans have actually bent their mind around the concepts necessary to begin to make three dimensional tools and that is a long story, that is a story that took several million years. The simplest conception of an artifact is essentially a combination of geometric and topological properties and what I will show you in a moment is a Oldowan chopper and what you can see there is that there is a line of little chips that were taken off a piece of stone and that that is actually the earliest evidence that we have of something that is aligned So the cognitive complexity of stone tool conception seems to me to be an indicator for short-term working memory development and you can make similar arguments for all kinds of other parts of human development. Let me now very briefly first give you an overview of the various kinds of activities that we can see in this stone and you should look at the column concept which is the second column from the left where we begin lets say in stage three to look at the fact that people were able, or whatever they were called in those days, were able to take one little flake off a piece of stone, that demanded indeed three different things because it demanded the stone with which you hit, the stone that you hold and the cognition of the angle with which you can actually hit that stone so that the flake comes off; that incident angle has to be less than ninety degrees. On the right hand side you will actually see in the red column that that is the stage three of that short-term working memory evolution and we have the tools in this particular case in a site called Lokalalei in East Africa where we find the evidence for this. What we begin to see then, much later, is that people do this repeatedly and initially that repetition is simply repeating the same act but in a second stage that repetition becomes a goal oriented, coordinated activity in which there is actually a strategy involved, those are the two stages that I have here called flaking and making an edge. What then happens is that you would get an edge and when you make the edge complete you actually have encircled a surface and what we see then is that initially in the stone tool manufacture what happens is that you get the edge first and then people take off the surface and then later they take off the surface first and then start by working on the edge, now that reversibility proves that conceptually they actually distinguish between the two dimensions, the single dimension line and the two dimensional surface. In the next stage we actually see this again in three dimensions, and Im jumping a few stages here to get down at the bottom which is stage number seven where we actually start working completely in three dimensions. Let me now illustrate this with a few examples of stone tools, right here. On top you basically see dimension zero the point, then dimension one, the line, you basically have an edge. The second dimension is the surface and I just talked about that and the third dimension finally we get to the volume. In order to get there much, much, much, much later we actually get a procedure that distinguishes between a surface there, a surface there and a surface here that is the only way you can explain that these particular tools were being made. Now that is an interesting sort of thing because it allows us to follow through time what the evolution of the capacity of humans to begin conceiving in three dimensions, how that evolves. Of course all that time they dealt with objects that had three dimensions but they were not cognized dimensions and what I am talking here about is the evolution of cognition. Here you have some of the earliest examples on the left hand side, a clever from Olduvai which is one and a half million years old where you basically have a couple of flakes removed on the side and that creates the cleaver, on the right hand side you see the next stage which is already a lot better, where the edges have been worked all around or to a large part around and where the object therefore gets a lot more shape. A particularly critical stage is what technically we called the Levallois Technique and that points to something else. It points to the fact that if you want to start making objects in series you want to find ways so that taking off one object, one flake prepares for the next and so people are beginning to learn that and they do that by actually conceiving of a stone as two halves or two parts and working on those two parts alternately so that they can actually get into that kind of continuous activity, this is the result and what you see here is of course that through time we gain a huge amount of control over the objects that we actually make, you have only to compare the Oldowan chopper and the Solutrean blade to see how much of that control we are getting but you have to remember that that takes actually about a million and a half years to get there. And it is my contention that that process, by the time we come to the Solutrean blade lets say, has achieved the capability of seven factors in our short-term working memory and that from that moment on we actually havent, from then till now, which is only a relatively limited amount of time of lets say a hundred and fifty thousand maybe two hundred thousand years, we havent really evolved that biological capacity any more. But then we havent had to because by the time you have the possibility to deal with seven factors, the combinatorics are such that you can actually deal with a huge number of different things so biology is no longer a constraint. What then becomes the constraint is to extricate experimentally and by thinking and by working different conceptual tools with which we can actually begin to build more and more complicated objects. So what we see at that moment and that is from about fifty thousand BC onward we see an explosion of new operations, so there is no longer a constraint we can do for that moment at least a very wide range of things. Now what happens at that moment? My basic theory is that from that time onwards we see a feedback loop in information processing and I am very deliberately therefore arguing that not only our society is an information society but that every society in the past and in the present is essentially an information society and that what determines the growth through time of the demographics, the technology and everything else is that feedback loop between being more innovative, coming up with more concepts, being able to do more things, because of that, encountering also more and more challenges, having after a certain moment no longer the capability to deal with those with a very small group of people so assimilating a larger and larger group of people and that is the sort of process that from that time lets say fifty thousand BC onwards I am actually talking about and that then leads to major social transformations. And lets very briefly summarize what is available, and I have not pointed to all of them, conceptually around fifty thousand years BP. On the one hand we can distinguish between reality and conceptions, between the objects and our ideas about the objects. We can categorize based on similarities and differences we feed back, we feed forward, we anticipate and that to my mind is a very much underplayed element in this whole story and we can actually reverse between looking backward and looking forward so we can develop memory and control loops, we can generate mentally events that could be different because we are basically able to deal with choices, we have options and we realize certain options and leave others untouched. We also hierarchize, we hierarchize between zero, one, two and three dimensions but we hierarchize in size and I will show you some examples of that in a moment. We also are able to distinguish parts from a whole and in different ways that is what I have here called partonomies. Basically one of the things that we see in this whole story is that initially people or whatever you call them go for these very large stones that are the cores and they take things off to create the shape they want but at the time, around fifty thousand, they inverse that process and what they are doing is they use the flakes that they take off and they throw away the core. So that difference is also one that we can demonstrate. And then finally we begin to see more and more complex ways in which the stages of production are actually intertwined because when you make something each step also has consequences for later ones and sometimes in order to get the product you have to reason back from the later ones to the earlier ones and that begins to be possible. Another thing that we can do by that point is reduce dimensions, we can picture, make pictures, paintings of three dimensional objects and actually depict them in a realistic way in two dimensions. Now how did all these people for this whole Pleistocene essentially survive? On the one hand by not investing in the environment, by only harvesting what comes out of the environment, by following a multi resource strategy and if things didnt work out in one place anymore simply moving somewhere else so adapting to change in a spatial way and I will get back to that later on because one of our problems is that we can't do that anymore. And also by systematically staying below the environments carrying capacity. One of the interesting data that we have from Australia is that the only place in Australia where people systematically have famines in prehistory is in the lush forests of the Murray and Darling rivers because there people were lured into the idea that they could actually have more and more people and then they get tapped on by famines; in the very sparse areas of Australia you never have any famine, any trace of famine, we find famines in the bones and that is why I can talk about that. The other thing is that people did not know how to interact with the environment, they only reacted to it so the environment was essentially left alone, change and risk were imminent all the time, every minute of the day but because they were, there was no accumulation of risks and I will get back to that later on. People did to some extent choose locations where they minimized change; for example, and this is something that applies to this region where you are living, where we find in Greece that prehistoric people at the end of the Paleolithic choose the tectonically very active areas and why do they choose them because those are the areas where nature itself puts itself regularly back to stage zero where there is no long term change because that is interrupted all the time by the tectonics. These are some of the tools that come out of that phase and when you compare with earlier images you can see they become much smaller, they become composite like at the top right hand image, you get with neolithic complete control over shape by first taking off large flakes, smaller and smaller and smaller and then finally grinding it so that you take out individual grains and that gets you complete control over shape and at the same time what you begin to get is things like basketry and I have given here the examples of a fish trap and some reconstructed basketry, what is interesting there is that we start from the small, we start from the single fiber or the single twig and we first make them into long one dimensional things and then we make them into two dimensional things by weaving them or in another way combining them so those scales are things that are normally operated. Around ten thousand that control over shape then is complete but we also see interesting things like for example that fish trap but also pottery that gets introduced at that time. We see for the first time a completely different topology. We see a topology of a solid around a void, that up to that moment all the objects are solids but they are never a solid that has a shape around a void. That means that by that point we have a tangled hierarchy of concepts, surface that defines a volume and that is defined by yet another volume, so we begin to stretch that mentally as it were. We also begin to invert the sequence of manufacturing. One of the real problems with stone tools is once you make a wrong blow, you have blown it and you will have to start over again, you can't correct. By the time you begin to create your two and three dimensional objects from the little pieces to the big pieces you can actually correct and so you have a much better chance of coming to an end result and that happens with clay, that happens with basketry, that happens with weaving. And at the same time, and pottery is there a very good example, you actually stretch temporal sequences. I need to hurry a little bit because we are going a little bit slow. Now lets look at the next phase that is these last ten thousand years. We all think about climate but we very often dont realize that that period is an incredibly stable period compared to the earlier periods that we have talked about. And that leads then also if you combine it with the changes that are happening there to an interesting question, is climate the driver or is climate the enabler? What we see with the neolithic is people start settling down, they start doing agriculture, they start raising animals, they have all these new technologies, they begin to live in villages, they begin to live in larger groups and they get a different perception of space and time. One of the interesting things out of the Australian data and in particular the story about the songlines is that there, time and space are actually intertwined in a very interesting way. Every individual learns certain songs but those songs only get a sense when that person goes through the space that they described and so there is a feedback between the spatial and the temporal. There is not a two dimensional map in their head, its a one dimensional map and its a one dimensional map that is hung on to time which is very different from what we do later on. If you look at a book like Hugh Brodys on how in areas where there is no maps people actually defined their territories it is very much a two dimensional sort of pattern. A crucial difference here is that people go from harvesting the environment to investing in the environment. People start taking out forests, burning down the stuff that remains after they have cut down the trees, planting, harvesting all of that is a longer timeframe so time is something that is beginning to get conquered. Now mobility at that point drops out at least to some extent as the way to meet challenges and the question that we have always been told is well that is because of the Neolithic, that there was some sort of progress idea that that meant that we could finally do those sorts of things. My sense of it is that that mobile system could have continued until the present day and that it would have been fantastic in the Neolithic because it wouldve be lot easier in some ways. So the question then is, what drives that change from the Pleistocene to the Neolithic, and my sense of it is that is the conceptual, the cognitive rather than anything else. These are some of the images that go with this, you see the villages, you see Stonehenge, you see the Neolithic plowing, we have the traces of the plowing and we have the plows as well. We suddenly also begin to see three dimensional art objects which is a very different story from what we had before. These are some other images of villages particularly to show you that they can be very, very different depending on the climate if you compare Skara Brae in the Orkneys with Catal Huyuk in Turkey, you can see how different that is. But what did it do? It changed the dynamic with the environment and climate. It is now no longer only people responding or harvesting things that are done in the environment, people actually impact on the environment and we will see in a little while that there are instances where we can actually see that impact. We intervene more and more in nature, we try and control our environmental risks by simplifying our environment, for example by extricating from the wild an area in which we do agriculture, over which we actually have control. We diversify spatially and technically. And as the system of course integrates it also becomes more vulnerable to all kinds of disturbances. So the emphasis shifts to problem solving and that is part of that feedback loop that I outlined earlier on. And as part of that we see people diversifying in particular challenges, particular problems and we see larger and larger interactive groups, its the beginnings of people really dedicating the time it needs to deal with specific issues. The cost of it of course is growing social complexity and that means more conflict and you have to find ways to begin to deal with that conflict. And now we come to the next step which is for me what I would call the sort of second revolution which is the origins of cities, and Stewart and I talked about this a little bit beforehand, I am going to try and argue that urbanization is not as it has been seen for a long time a way to be more efficient, at least not in energy terms. Once you get a over certain threshold of size of the population it means that you have to get your food so far away, your footprint becomes so large that it becomes actually from an energy perspective very uneconomical to do that. So my point here is that it is again the need to make a more efficient way of dealing with the information processing that brings people together, by bringing them closer together communication is made a lot more efficient, people get more direct contact, more intense contact and that means that ultimately there is a possibility to innovate more effectively in the city then there is outside and what is happening at that point to my mind at least is that you get a sort of flow structure in which from the city organization goes outward, new ideas or innovations go outward and once they are outward they facilitate the bringing inside into the city the energy that is necessary to feed all the people that are there. But for those kinds of structures, dynamic structures, to survive basically means that innovation becomes a permanently necessary thing because otherwise people at the periphery after a little while are no longer interested in participating in this whole game. The other side of that is that of course by bringing an invention in a city where there are people with very many different perspectives we also see that that invention suddenly gets enriched by being in a much larger cognitive sphere and therefore the possibility that it will actually take off is enhanced. One of the interesting things about cities is that they emerge in clusters and I have given you here some examples whether its Etruria or the Maya. And other things that happen at the same time but that are important to understand this are the capability of counting, the capability of writing. What you have in the left hand side at the top are tokens, tokens that according to a colleague Denise Schmandt-Besserat are the antecedents of actually the first tablets and the first writing because they signify an animal or an object and they are given to somebody who transports that object as a sign that that is what it is so they are also counters in a sense. Ultimately that leads to making impressions from those objects in the tablets. In the Maya area its done differently, in the Peruvian area on the right hand below its done differently yet again but what we see in every case is there is a need to have a material means to carry across time and space certain symbols that say something about what is going on in the society. At the same time ones we get people together we need to solve conflicts, we need to do administration and what we see on the left hand side is the famous column of the laws of Hammurabi, at the top we see a clay tablet in cuneiform that here symbolizes the fact that you get a bureaucracy and below that the Egyptian scribe does the same thing and on the right hand side you see an actual archive that was excavated in Syria about thirty years ago. So those are aspects that occur at the same time and that to my mind are very much part of that transition, they would not have been there if you hadnt had people in the cities together. The next revolution is that this same things happens on a much larger scale and that is what I have called here the imperial revolution. When cities get up and running and attract more and more people, more and more energy is needed so that has to come from further and further away and ultimately that comes from so far away that it comes across cultural boundaries, across linguistic boundaries and that is only possible for a particular reason that I will mention in a moment when there is, in those areas to which the power of the city expands, treasure that can be taken in and that can actually pay for the act of extending the empire. One of the beautiful arguments launched by a colleague here in the United States that I appreciate a lot Joseph Tainter is that the Roman Empire was only able sort of to spread on the back of an earlier phase in which organization had spread and treasure was accumulated and that as soon as the Romans could no longer find new treasure the empire actually started getting into trouble. Part of that process is of course that power to do things becomes power over, control becomes important, institutions, formal institutions and their roles. From conflict resolution we get to the stage of resource and people management, roads and communication became important and that is what this slide is all about, the left hand side shows the expansion of the Roman empire through time and the right hand side shows the huge network of roads that are another component of this need to communicate more efficiently and to exchange more information that spread over the empire. Now the first moment that we have actual anthropogenic climate change is in that Roman period and its not on a global scale. This graph shows a whole series of ways of registering climate change that relate either to the polarized caps or to the atmosphere that are truly global. The only one at the bottom, the black one, is a regional one and it is based on erosion of soil and there we see suddenly a peak in the second century AD that doesnt appear on a global scale and so we actually argue that that is the result of human intervention because the Romans at that point institute what I can only call a sort of proto-agro-industry all over the empire to feed people in Rome. This is the collapse as soon as there is no longer treasure to be had the Romans get to the edge of the empire, the Rhine, the Danube, the desert in the south and its very interesting to hear Caesar complain when he gets to Belgium, I am a very good soldier, I do a lot of fighting, but I am useless here because there are no things that I can conquer, there are no armies that I can conquer, there are no cities that I can destroy, there is none organization, and so I cannot do anything here anymore. What you see at the same time on the right hand side here is that once that stage has been reached, that there is no new treasure to be found, you see by the devaluation, the debasement of the Roman coins how actually the inflation must go very, very quickly, very high up. And ultimately by the end of the empire we find that local entities detach themselves from the empire, and how do we find that? We have a fantastic sources in the south of France, you may have seen the Pont du Gard, which is this fantastic Roman aqueduct. Well if you look inside it and you analyze the calcium carbonate that is deposed by the water on the edges you can do that sort of by periods of twenty, thirty years and you see that from the third century onward the water becomes actually very dirty, you see that people start tapping it out of the aqueduct for their own latifundia so that the city no longer controls even its own hinterland. That to my mind is how things go until around 1800. By 1800 with the industrial revolution we have actually temporarily solved the energy constraint, we begin to use fossil energy. And when we do that, innovation explodes and very quickly our societies become dependant on innovation and that is where we are now. Innovation becomes endemic, you could say, because that is a word that has recently been used a lot in the financial crisis, that innovation is the biggest Ponzi scheme of all because you have to keep going and going and going and going and going faster otherwise it wont work and that is where we are at this particular point. And on the left hand side here you see actually how the energy needs and the energy use hugely expands. We use in our society about ten thousand watts per person. A human being needs a hundred watts, the other ninety nine times a hundred watts actually go in maintaining our society and our material culture. Okay, what is the underlying pattern, and I have to go fast on this, but I just want to basically say that ones the biological constraints to innovation have been overcome we see innovations leading to challenges leading to innovations. Humans overcome every major hurdle every time, but they do so by very fundamentally changing their society and how they are actually organized. How is that dynamic driven? And to my mind it is driven by a tangled hierarchy between two perceptions of the relationship between society and environment and I am getting to that in the next slide. Based on the work of people like Kahneman and the Stanford School, we know that there is a relationship between the direction of a comparison, whether it starts with a subject towards a reference or the other way around, that determines whether we stress in a comparison in a categorization, similarity or dissimilarity. As a result we find and we have documents in ethnography that certain categories can be open that is we know what may be part of them but we dont know yet what wont part of them, whereas at a later stage when that comparison has also turned in the other direction we actually close the category and then we know what is in it and what is not in it. Apply that to the environment and think about it and I have taken these two French words milieu and environment because they are both still actively used in the language. In the case of milieu, humanity is compared to nature, the cohesion of nature, its unknown aspects and its strangeness and force are amplified. The confusion and the handicaps of humanity are accentuated, humanity is passive in a natural environment that is active and aggressive, change is attributed to nature and people have no other choice but to adapt to that. So natural changes tend to be viewed as dangerous because they are beyond the control of humanity. Now look at the other perspective that inverts the two, the society and the environment, and there nature is compared to humanity. The cohesion and the strengths of nature are diminished and its known aspects are emphasized, the cohesion and strengths are accentuated in humanity, humanity is active and aggressive in a natural environment that is passive. Humanity tends to be viewed as the source of all change, people as creating their environment and over the last fifty years we have actually gone through both those stages but right now we are at a point where we are beginning to look at their interaction and the interesting thing to my mind is that these two opposite perspectives reinforce each other in one particular way: that natural dangers are exaggerated and those of human intervention are systematically underplayed and undervalued so that we intervene more and more in our natural environment because we think that we thereby reduce our risks. But what we dont know and we dont realize is that we are also only changing the spectrum of risks, we are not in anyway reducing the risks. So ultimately society loses control because the more it transforms its surroundings the less it understands them. That leads, and this is a known fact for example that we have studied at length all across the Mediterranean, that complex ecological systems consist of hierarchies of dynamics on all kinds of scales, that the faster dynamics take control over the slower ones and usually these faster ones are the human ones. But ultimately there is a role reversal between the two, the human dynamics that are rapid but initially didnt have much impact because nature dominated very much, begin to control the slower and natural dynamics that are more encompassing. So what happens is that ultimately and this is, Israeli colleagues have studied this in great depth, that landscapes become what we call disturbance dependant, they become dependent on humans to actually be maintained as they are. And finally, talking back on that risk spectrum, any societys risk spectrum shifts over time with respect to its environment. Because what we do is we over emphasize the frequent risks that we see regularly, we do something about them, we reduce them, we take out those frequent risks and we substitute by our actions into the environment completely new, completely unknown risks of much larger, at least some of them, of much larger temporalities and so ultimately what I think you see they said you get a risk barrier, by analogy to a sound barrier, you get a build-up of risks that ultimately creates a collapse. Okay, I think I would then summarize. At some point, any social-environmental system will go out of control because those dynamics that I have just outlined are irreversible. What points in that direction? The appropriation of nature, the human perception of the relationship between people and the environment, the risk perception and the relation between cognition and action which I have not really gone into here but I can do that in the discussion if you want. The effects are that the system pushes itself into a trap that short-term solutions create long-term problems that the cost of problem solving goes up, flexibility goes down, we get a number of those time bombs and then the real question is the outcome at the end of, for example, the Roman Empire and how far is the way it ended already included in the way it was started, that is, in how our perception of our environment has exploited that environment and by exploiting it, has created the weaknesses that we get confronted with at the end. And now this is really the last slide, this is then, we are now at a completely new stage. For the first time we are beginning to get control over information itself, we have control over energy, we have control over matter. We are facing an incredible transformation in the next fifty years in nanotechnology, biotechnology and what have you. In order to shape our future we must first of all, and this is I think the main thrust of my argument here, understand the process of innovation itself. What we dont know is how we relate our perspective on the past, our lessons from the past, to the future in a scientific and coherent way and that is something we can discuss later in the discussion a bit more in detail, I have some ideas about it, but it has to do with the fact that because we have this limited short-time working memory, we basically cannot handle the total complexity of the phenomena, whether they are past or future. For the past we get out of that by creating a narrative that tells us how the past was and that can be changed as archaeologists do at every occasion. If we look towards the future, we dont do that, we set out a path and then simply say Well it has such and such a probability. We need to get into that dynamic if we are going to be able to solve some of these things and I do believe that modern information technology can actually help us with that in some ways. And then in the end, of course, if we manage this, we will actually have to adapt our social structures, our institutions to this much better use of innovation because in the end it is the rampant innovation of the last two centuries that has lead us to the crises where we currently are. Thank you very much.