 Well good morning everybody, welcome to our session What Haven't You Found? So very kind of negative start to the beginning of a conference that introduces a topic which really hasn't perhaps had the attention but it's deserved over the last few years. You'll hear more about this in due course. Roger Thomas, one of the organisers is with me, I'm Tim Darvill and Φrift Llywth is in fact in the field at the moment and therefore hasn't been able to come over and join us ond mae'n gweithio'n sgwyddiol a woes iawn. Mae'n gofyn i'ch gweithio'n sgwyddiol a'r hwyl iawn. Mae hynny'n taeth eich cyfrifiad, S571 i chi'ch meddwl. Mae'r cyfrifiad y gallai gwaith o'r hwyl iawn a'r bwysig i'ch meddwl yn cael ei gweithio'n meddwl. Rwy'n cael ei wneud ymgylchau. Mae'r cyfrifiadau yn cyfrifiadau yn ymgylchai yma a'i gyda'n ei wneud â hyn ychydig. I have to attend for some family issues over in Canada, but I'm going to be filling in with a short paper which I'm just writing at this moment to fill that gap, so that might help us a little bit there. As I say, this is a relatively new topic and one that deserves some further attention. And to introduce it to us, Roger is going to think about the issue of blank areas and the value of negative evidence to set us off. Roger. Thank you, Tim. Well, thanks very much for all coming along to learn about this early, to learn about the joys at blank areas. We weren't sure if we'd turn up to a blank room or alternatively a room full of people telling us we were mad to talk about this topic. So it's good to see you all. Traditionally archaeology has been focused on finding and excavating individual sites and monuments. That's been certainly true in the past and in some places still true now. And so in that perspective, the idea that finding nothing confusing does actually seem quite strange and we made the title deliberately provocative. But as Tim said, this is something people have begun to start thinking about. And actually we were fantastically pleased with the range of abstracts that were submitted because they did show that a lot of people independently seem to be thinking about the same kinds of issues. So we were really pleased about that and we're looking forward to hearing all the other papers. And I just wanted to look quite briefly at why this is an interesting subject and outline some different aspects of the topic. And we think that this interest in, I've put the phrase at the bank Thomas in inverted areas because it's a very low and difficult phrase and we may want to talk more about what we mean by that. Blank areas are negative evidence, which is another way of looking at it or confirm negative evidence. And we think that interest comes from three linked developments in archaeology in recent decades. Landscape archaeology, looking at things in the big scheme of things. Kind of linked to that, the theoretical interest in the social use of space, how people use space, use land, use the landscape. And then the third thing, which is really probably the thing that's focused at the mind of Tim and me on this subject, the results of very large scale development like archaeology, particularly on big infrastructure schemes, motorways, railways, mineral extraction, that kind of thing. And we'll all be familiar with the kinds of results that are coming from that sort of work. Landscape archaeology, I don't need to say where it is an approach and a methodology which looks at the whole landscape, not just the sites. And it considers how sites and how people in societies operated in a wider geographical context, the way they lived in their environment in their landscape. And there's been a lot of theoretical and practical interest in landscape archaeology in recent decades. There's a long tradition of landscape archaeology in the United Kingdom and it's been considered in many other areas as well. And there are obvious links, the sort of theoretical interest in the social use of space, people like Tim Ingold with his idea of task scapes and things like that. So landscape archaeology is where we're coming from in this, in a way. Although it's perhaps worth saying that a lot of our landscape archaeology certainly in England has been, or the United Kingdom, is about using non-intrusive methods. It's about surveying things that exist above the ground rather than about excavating them. So these big developments mean you can do excavations on a sort of landscape scale. Development-led archaeology in Europe, again, don't need to say this. It expanded greatly after the Valletta Convention and has led to many huge archaeological investigations. And I'm sure many of you may have worked on them, you'll all be familiar with the results. And many of them are on large-scale infrastructure projects like motorways, high-speed railways, long-distance pipelines, airports, big quarry sites. Things of that scale, things that cover tens or hundreds of hectares or tens or hundreds of kilometres of linear excavation. And because of their scale, landscape approaches are very common in this kind of work. And particularly because it kind of mirrors the way these projects are developed approaches which sort of start with a big picture and maybe think we're going to put the motorway there or there. And then progressively focus in starting with very broad, extensive methods and then focusing in down sort of quite intensive methods like open area excavation, but used on a very huge scale. And certainly in England enormous amounts of money are being spent on this kind of archaeology, millions and millions of pounds or euros, even tens of millions on some projects. And in this process, as I've said before, tens or even hundreds of hectares of land may be stripped, cleaned and investigated archaeologically. It is really on a staggering scale. And in some areas like parts of southern England, which I'm familiar with, southern England, development-led work finds so much that actually finding nothing, if you expose a really big area, is quite unusual. Now that's partly because we look in places where we already think that we'll find things, but equally to strip a really big area in southern England and find nothing at all is pretty unusual. If you strip, say, a square kilometre and some projects are on that scale and found out nothing, you would really be asking yourself what that was, why you hadn't found at least a Roman settlement or a couple of neolithic pits or whatever. So that's the kind of thing we're thinking about. So that issue and work on this scale and considered in the landscape archaeology has sort of put our attention onto this question of the blank areas between sites as well as on the sites themselves. Of course, the thing that's why this term blank areas is loaded because you can use it and it kind of makes you put it out of your mind if you say it's a blank area, but actually they weren't blank in the past. Obviously they were part of people's landscape. There were their fields, there were their forests, there were their pastures. They were almost certainly used in ways that are leaving archaeological traces that we don't find or no traces at all, and even if they weren't very much used, they would still have been part of people's landscape and part of their kind of mental geography and maybe symbolically very important, like forests and things. Who knows, but that's why the term blank areas can sort of lead us in the wrong direction. In the past, and this is sort of assuming that, it was often uncertain if blank areas really were empty of archaeological remains or just because they hadn't been investigated, and that's why it's an ambiguous phrase because you say blank area and you're never quite sure if that's because there's nothing there or because we simply haven't looked. And now, and sometimes even if you had looked, it could have been ways or in conditions that didn't reveal what was there. But now large-scale work of the kind I've been talking about can give us much more confidence in confirmed negative evidence or true negative and I think Tim's going to be talking a bit more about his impromptu filling in of the absent speaker about this issue of true negative and false positives and all that kind of thing, which is a way of looking at things well-known from other subjects, particularly medicine where you don't want false negatives particularly. And confidence in negative evidence depends largely on the techniques that he used and there is a kind of gradient of confidence if you like. And there are various forms of extensive survey, error of photography, geophysical survey, surface artefact collection. You can have some confidence in those, but they're very much affected by the conditions, by the geology and so forth. I mean error of photography is notoriously precrecious. It doesn't work so well on some geologies as others. Sometimes crop marks will show in one year or under one crop, not under another. So I think you have to be quite careful to use error of photography to say this is confirmed negative. Geophysical survey works better on some geologies and soils than others. If you're working on a soil geology where you know that geophysical survey is effective and you're doing it right and it says there's nothing there, you can be reasonably confident that you haven't missed anything really big and major. I mean somebody may shoot me down but I don't know, we'll see. So anyway, there is a sort of gradation of confidence in negative evidence. Diagnostic trenching, what we quite often refer to as field evaluation, digging a kind of array of narrow trenches across an area, maybe sampling between 2% and 4% of the surface. I think that allows you to identify major sites or the lack of them with a high level of confidence. You probably wouldn't miss a Roman villa if you were sampling in that sort of way. Well, if you were doing it properly. But if there was a very small rich prehistoric burial or something that was an isolated feature, you might well miss that because it could easily fall between 2 trenches. But I mean, typically our trenches are what 30, 40, 50 meters apart. So anything that was bigger than that, you would expect to find it if you were doing it right. But again, it's an area in which things can go wrong and in which being overly confident results of diagnostic trenching can lead you into problems. So that's something we might want to talk about. Open area excavation where you strip down to the subsoil and clean it up and look to what's there will give you a very high level of confidence in the presence or absence of features which are cut into the subsoil. And there is an important issue in that about kinds of archaeology that don't have features cut into the subsoil which exist entirely in the topsoil and plousoil and which if you strip it off by machine and then say there's nothing there, well, there wasn't. There was something there, but you've put it on spoil heap. So that's something we might well want to come back about. And I think Chris Evans would have had a few things to say about that if he'd been here. And this sort of follows on from that. The relationship between techniques and the character of the archaeology. If, just saying, if the only evidence is artefacts in the topsoil and you remove it, it'll look as if there's nothing there, that won't be right. And also some periods have much more substantial traces than others. I mean, you know, the Romans left a lot of pottery, building material, metalwork, coins and things around. So if you've got a high likelihood of recovering that if it's there and if you look carefully and don't recover it, you can be fairly sure it wasn't there. Neolithic materials say the pottery can be much more fragile. And it's features, unless it's a major ceremonial monument, the domestic features can be certainly in parts of what I know. I can be quite slight so you could more easily miss those. So you need to think about all of these things when you're saying, you know, is there anything there or not, or how much is there there. This sort of led us on to thinking about chronological patterns. Some areas may produce no evidence of activity any period, and I suspect that's probably rare across much of lowland Europe, if I can put it like that. What's kind of more interesting, in a way, is that other areas can produce a lot of evidence of some periods, but little or none of other periods. We're going to be hearing about cases in this later. And that's very important because it's kind of telling us about local and regional patterns of colonisation, of occupation and abandonment, and kind of different trajectories of settlement in different geographical areas. And certainly, again, in part for what I know, it's quite evident that there are shifts. You'll have a lot of, say, bronze age material in one area, not very much iron age, and then, you know, you can have a lot of iron age in another area and rather less bronze age. Seeing these or beginning to be able to perceive these shifts. And because of the scale of work that's been undertaken, we can now be much more confident about saying there isn't material or much material of a particular period in an area, you can be much more confident in detecting those sorts of patterns. We think that sort of focusing on this issue of blank areas can help us in both in academic research and in heritage management. Obviously, understanding the blank areas helps us to understand past settlement and land use, and as we were saying, these chronological patterns of regional and local colonisation with implications for the wider and long-term evolution of societies. And implications for heritage management. Understanding these patterns can tell us what's like to be found and where, which areas are more or less rich and remained. And if you do find something in an area where there is very little, then in a sense it's more valuable because it's more unusual than if you find another Roman settlement in an area where you've already found, you know, dozens and dozens of them. And this leads on to something which is very, very important, and this is the importance of, and it's something that has been neglected, the importance of recording and publishing in inventories, negative investigations. To say, yes, we did an excavation here and we didn't find anything and putting that in the record, and it's something which I think hasn't been done in the past. And it kind of leads me on to the last point I want to end on, which is taking us a little bit beyond the scope of this session. But traditionally, and this is gross caricature really, archaeology has been about studying old things in a way, in terms of characterise of the Santa Aquarianism. But when you start to think about confirmed negative evidence, it does bring home to us that the evidence that we have really depends on the kinds of observations that we make. And I just wonder if we're becoming more conscious of our sort of places in observational science, if you like. I mean, for scientists, it's absolutely standard to record the scientific procedures, the way you've made your observations as part of the report on what you do. And that enables everybody to assess the validity of the results. A lot of excavation reports are quite cursory on that. They tell you we excavated a pin, but they don't tell you whether it was done with a bulldozer, a shovel, a trowel, or everything serious. So you have to kind of guess how much may have been recovered and how much lost. So are we moving towards one where it's just as important to record how we observe as what we observe? And this thing about recording, we did an excavation, we didn't find anything, I think it's part of that. And maybe this sort of interest in understanding how our data has come about is seen in other areas of the subject, particularly kind of these big data studies which are being done now where you really need to understand characteristics and origins of our data. What kinds of looking did we do? And how does that affect what data that we have? So I think I'll stop there. That's the revised programme that you've all worked on in front of you. Thank you very much for listening.