'Natural Catastrophes During Bronze Age Civilisations:
Archaeological, geological, astronomical and cultural perspectives'.
A conference at Fitzwilliam College. Cambridge. 11th-13th July 1997
Organised by The Society for Interdisciplinary Studies.
Benny J. Peiser, Trevor Palmer and Mark E. Bailey: Introduction. [See text below]
Robert A. J. Matthews: The Past is our Future
Mark E Bailey: Sources and Populations of Near-Earth Objects: Recent Findings and Historical Implications [abstract].
Bill Napier: Cometary Catastrophes, Cosmic Dust and Ecological Disasters in Historical Times: The Astronomical Framework [abstract].
Duncan Steel: Before the Stones: Stonehenge I as a Cometary Catastrophe Predictor [abstract].
Gerrit Verschuur: Our Place in Space [abstract].
Bruce Masse: Earth, Air, Fire, and Water: The Archaeology of Bronze Age Cosmic Catastrophes. [abstract].
Marie-Agnès Courty: The Soil Record of an Exceptional Event at 4000 B.P. in the Middle East. [abstract].
M. G. L. Baillie: Hints that Cometary Debris played some Role in several Tree-Ring dated Environmental Downturns in the Bronze Age [abstract].
Benny J. Peiser: Comparative Analysis of Late Holocene Environmental and Social Upheaval: Evidence for a Global Disaster in the Late 3rd Millennium BC [abstract].
Amos Nur: The Collapse of Ancient Societies by Great Earthquakes [abstract].
Lars G. Franzén and Thomas B. Larsson: Landscape Analysis and stratigraphical and geochemical Investigations of Playa and alluvial Fan Sediments in Tunesia and raised Bog Deposits in Sweden [abstract].
Bas van Geel, Oleg M. Raspopov, Johannes van der Plicht, Hans Renssen: Solar forcing of abrupt Climate Change around 850 calendar years BC [abstract].
Euan MacKie: Can European Prehistory Detect Large-Scale Natural Disasters? [abstract].
Gunnar Heinsohn: The Catastrophic Emergence of Civilization: The Coming of Blood Sacrifice in the Bronze Age Cultures [abstract].
David W. Pankenier: Heaven-Sent: Understanding Cosmic Disaster in Chinese Myth and History [abstract].
William Mullen: The Agenda of the Milesian School: The Post-Catastrophic Paradigm Shift in Ancient Greece [abstract].
Irving Wolfe: The 'Kultursturz' at the Bronze Age/Iron Age Boundary [abstract].
S. V. M. Clube: The Problem of Historical Catastrophism [abstract].
Publishing DetailsBritish Archaeological Reports -S728, 1998. Natural Catastrophes During Bronze Age Civilisations: Archaeological, geological, astronomical and cultural perspectives. Edited by Benny J. Peiser, Trevor Palmer and Mark E. Bailey. ISBN 0 86054 916 X., pp.252. 39 photos, 46 figures, 13 tables, Publ. Archaeopress, Oxford.
British Archaeological Reports -S728, 1998.
Edited by Benny J. Peiser, Trevor Palmer and Mark E. Bailey. ISBN 0 86054 916 X., pp.252. 39 photos, 46 figures, 13 tables, Publ. Archaeopress, Oxford.
For availability and price, contact ARCHAEOPRESS, Gordon House, 276 Banbury Road, Oxford OX2 7ED, UK. Email
The Second SIS (Society for Interdisciplinary Studies) Cambridge Conference, entitled "Natural Catastrophes during Bronze Age Civilisations: Archaeological, Geological, Astronomical and Cultural Perspectives", was held at Fitzwilliam College between 11-13 July 1997. The one hundred or so participants, who came from as far afield as North America, Australasia and Japan, as well as from all corners of Europe, were a vibrant blend of enthusiastic amateurs and professionals from all the subject areas under consideration, in keeping with the traditions of the SIS. The event was dedicated to the SIS Vice-Chairman, Geoffrey Bennett, who organised the First Cambridge Conference, but was unable to attend the Second because of terminal illness.
The SIS was formed in 1975 to provide a forum for the discussion of all aspects of catastrophism and chronology. At that time, the gradualist paradigm was supremely dominant, as it had been throughout the previous hundred years, and any attempts to suggest catastrophist explanations for events in geology, evolution or ancient history were viewed with great suspicion and generally ignored [12, 28, 30, 41]. That fate certainly greeted the publication in 1948 of Claude Schaeffer's "Stratigraphie comparée et chronologie de l'Asie occidentale" , despite the eminence of the author, who at various times occupied chairs at the École de Louvre and the Collège de France . Schaeffer's main professional achievement was the excavation of a tell at Ras Shamra in Syria, which he was able to identify as ancient Ugarit.
On the basis of findings here and at other sites throughout the Middle East, Schaeffer claimed that there had been at least five occasions in the Bronze Age when catastrophic destructions occurred in widespread fashion, often with evidence of earthquakes and/or fire.
Two of these were in the Early Bronze Age, the first around 2300 BC, co-incident with the end of the Old Kingdom in Egypt, involving sites in Syria (Byblos, Hama and Ugarit), Palestine (Beth Shan) and Anatolia (Alaça Hüyük, Alishar, Tarsos and Troy), whilst the second occurred perhaps 200 years later, affecting many of these same locations, together with others such as Bait Mirsim, Jericho and Tell el-Ajjul in Palestine and Tell Brak in Mesopotamia. The end of the Middle Bronze Age was marked by destructions at many sites, including Ugarit in Syria, Beit Mirsim, Jericho, Bethel, Hazor and Lachish in Palestine, Alaça Hüyük, Alishar and Boghazköy in Anatolia and Tepe Gawra in Mesopotamia. This was also the time the Hyksos invaded Egypt. Schaeffer further claimed that there were two episodes of widespread catastrophic destruction in the Late Bronze Age, the first around 1365 BC, the time of the Amarna Period in Egypt, affecting locations in Syria (Alalakh and Ugarit), Palestine (Beit Mirsim, Beth Shan, Megiddo, Tell Hesi, Beth Shemesh, Lachish and Ashkelon), Anatolia (Boghasköy, Tarsos and Troy) and Mesopotamia (Chagar Bazar and Tell Brak), and the other around 1200 BC, bringing to an end some Bronze Age cultures, with destructions at most of the same sites in Syria, Palestine and Anatolia as in the previous wave [8,22,31].
Schaeffer was convinced that these catastrophic destructions were the result of natural events, rather than human activity. However, he was undecided as to the precise causes, although undoubtedly favouring the involvement of earthquakes. He did not consider the possibility of the involvement of extraterrestrial factors, a point picked up by the Belgian amateur geologist, René Gallant, in his 1964 book, Bombarded Earth .
Gallant (who was to become an SIS member, and who addressed a Society meeting in London in 1984, shortly before his death ) argued that the seismic activity and climate changes which, according to the evidence provided by Schaeffer, occurred at the times of the destructions, were both likely to have resulted from large meteoritic impacts. Bombarded Earth, however, received even less attention than Schaeffer's major work had done.
However, if the ideas of Schaeffer and Gallant made very little impression on the consciousness of others, a very different reaction, although one which was no more positive, greeted those of another catastrophist, the Russian-born psychoanalyst, Immanuel Velikovsky. Largely on the basis of myths from around the world, Velikovsky came to the conclusion that several of the planets of the Solar System had threatened the Earth in historical times. In particular, he believed that Venus had caused major catastrophes by passing close to the Earth at a time corresponding to the end of the Middle Bronze Age in the Middle East, and Mars did similarly a few hundred years later. These ideas were outlined in his 1950 book, Worlds in Collision .
Despite the mythological origin of Velikovsky's ideas, he made several successful scientific predictions in Worlds in Collision and at a graduate forum at Princeton University, a transcript of this talk subsequently being included as a supplement to his later book, Earth in Upheaval . Amongst these predictions were that Jupiter would be found to emit radio waves and that, contrary to what was generally believed at the time, the surface of Venus was very hot.
Furthermore, by comparing accounts of catastrophies in different traditions, Velikovsky came to the conclusion that the currently accepted chronologies of certain civilisations were incorrect, and that the supposed "Dark Ages" between the Bronze Age and the Iron Age periods in Greece (and similar ones elsewhere) had never existed. His proposals for a revised chronology for the ancient world were given in Ages in Chaos and subsequent books [36, 38, 39].
The eminent physicist Albert Einstein, who from 1921-1924 had been co-editor with Velikovsky of the Scripta Universitatis atque Bibliothecae Hierosolymitarum, from which the Hebrew University of Jerusalem was to grow, found his compilation of evidence for catastrophic events at the Earth's surface convincing, but not his proposed mechanism of planetary interactions. On the other hand, because of Velikovsky's correct predictions, he considered his ideas to be worthy of further study. Many other academics took a different view, however, and in America there was an attempt to suppress publication of Velikovsky's books [13, 40, 42].
For a while there was little knowledge of these events in Britain, but then, in 1973, archaeologist Euan MacKie wrote in New Scientist that, no matter whether Velikovsky was right or wrong, he had formulated hypotheses which should be tested in the normal way . In the same year, he suggested in Pensée that radiocarbon dating might provide the evidence for a test of Velikovsky's theories of global catastrophes and chronological revisions .
A year later, on the 5th November 1974, MacKie discussed related matters with Harold Tresman, Brian Moore and Martin Sieff over a meal at the Regent Palace Hotel in Picadilly and, as a direct consequence, the SIS came into being. The inaugural meeting took place at the Library Association Building, London, in November 1975, with Tresman in the Chair, and 70 members present . (Happily, three of the four founding members of SIS, the exception being Sieff, were present at the Second Cambridge Conference, with MacKie presenting a paper and Moore chairing a session.)
From 1975 onwards, regular debates have taken place at SIS meetings, and in the pages of the Society's journal, the SIS Review, later re-named the Chronology and Catastrophism Review. To avoid possible misunderstandings, it was made clear right from the start that the Society had been formed to examine the ideas of Velikovsky and other catastrophists, not to promote any particular point of view .
Of Velikovsky's several claims, the only one which has made significant progress towards widespread acceptance is his general one that the history of life has been shaped by major catastrophes to a far greater extent than his contemporaries realised. Partly that has come about because of increased knowledge of the threat from asteroids and comets in Earth-crossing orbits, together with the growing realisation that many of the craters at the Earth's surface, previously thought to be of volcanic origin, were in fact formed by impacts. Also, many previously-sceptical scientists started to become receptive to catastrophist arguments when physicist Luis Alvarez and colleagues showed, in 1980, that the end of the Cretaceous Period 65 million years ago, when the dinosaurs and many other groups of animals became extinct, is marked in rocks around the world by a high concentration of iridium. This metal is largely absent from the Earth's crust, but present in abundant amounts in extraterrestrial materials, and taken together the evidence suggested the possibility that the extinctions could have been linked to the impact of a large asteroid or comet [1, 6, 7, 23, 26, 28, 30, 33, 41].
So far as the historical record is concerned, orthodox opinion has remained unconvinced about the need to make any major revisions to the established chronologies of ancient civilisations, but challenges continue to be made. In 1978, the SIS, in collaboration with the Extra-Mural Department of Glasgow University, organised its first residential conference to discuss the issues. It was entitled Ages in Chaos? and held at the Jordanhill College of Education. The consensus which emerged at the conference was that there were indeed problems with the conventional chronologies but, equally, there were major difficulties with Velikovsky's proposed revisions [2, 11, 15]. Since then, several historians with SIS associations, including Gunnar Heinsohn , Peter James  and David Rohl , have gone on to propose revised chronologies different from those of Velikovsky, and from each other.
Velikovsky's belief that the planets Mars and Venus, now in stable orbits, could have passed sufficiently close to the Earth in historical times to have caused global catastrophes, cannot be reconciled with the known laws of physics, so, although planetary catastrophism still receives enthusiastic support in some quarters, it has been firmly rejected by professional scientists [27, 28, 33, 41].
The British astronomers, Victor Clube and Bill Napier, have acknowledged that Velikovsky may have been correct in suggesting that some myths might have been derived from objects which had been prominent in the ancient sky, and caused catastrophes on Earth, but these cosmic bodies must have been comets, not planets. By extrapolating backwards in time the orbits of Encke's Comet, the Taurid meteor stream and associated Apollo asteroids, Clube and Napier concluded that all were products of a huge comet which came into an Earth-crossing orbit around 20,000 years ago and began to break up, with particular disintegration events occurring about 7500 and 2700 BC. Fragments would have struck the Earth at intervals throughout the Bronze Age, with devastating consequences [6, 7]. Clube put these ideas before the general public for the first time at an SIS meeting in London in 1982, and developed them at another in Nottingham the following year [5, 23]. The model which he and Napier advocate, that small but frequent impacts occur as a consequence of the break-up of a giant comet, has been termed coherent catastrophism, in contrast to stochastic catastrophism, which involves larger individual impacts occurring in isolated fashion over long intervals of time [33, 40].
In an issue of SIS Review published in 1979, Euan MacKie followed up his earlier suggestion of using radiocarbon dating to test for possible correlations between catastrophic events in different locations by carrying out a survey of published data. He tentatively concluded that the end of the Old Kingdom in Egypt, which Schaeffer had included as part of the first wave of Early Bronze Age catastrophes in the Middle East, could also have been contemporaneous with the end of the Chalcolithic in the western Mediterranean, the fall of the Harappan civilisation in India, and the end of the Neolithic in northwestern Europe . One of the sites associated with the last-mentioned event, Skara Brae in Orkney , was investigated by Brian Moore and Peter James, who concluded that the evidence was consistent with a catastrophic destruction around 2300 BC .
More generally, archaeological, geological and climatic evidence for a world-wide catastrophic event around 2300 BC was presented in the pages of the SIS Review by the American engineer, Moe Mandelkehr [20, 21, 22]. At this time, for example, there were global crustal deformations, sea-level discontinuities, earthquakes, volcanic activity, a geomagnetic transient and a transient in the atmospheric radiocarbon concentration .
The First SIS Cambridge Conference, held between 16-18 July 1993, was entitled "Evidence that the Earth has Suffered Catastrophes of Cosmic Origin in Historic Times". At this conference, Bob Porter outlined the destructions which had occurred at various sites during the Bronze Age, and concluded that there was strong evidence of a widespread catastrophe of possible extraterrestrial origin only towards the end of the Early Bronze Age. Even here, however, there was doubt about the precise dating of events at the different sites. Catastrophic events at the end of the Middle Bronze Age, and at other times, remained a possibility but, if any had occurred, they were on a much smaller scale than had been envisaged by Velikovsky . A similar conclusion was also reached by the Old Testament historian, John Bimson . Both Porter and Bimson considered comets to be a far more plausible cause of Bronze Age catastrophes than planetary encounters.
All who attended the First Cambridge Conference considered it to be a great success, characterised by stimulating discussions on a wide range of topics. However, in retrospect, the SIS Council thought that, perhaps, the programme had been too wide ranging. Despite the title there had been papers on, for example, the age of the Earth, the age of Venus, and the identity of Job, and there had also been one (by Victor Clube) on catastrophes in the Christian Era, as well as those focusing on events in earlier times. Hence, when planning the Second Cambridge Conference, it was decided to narrow the title to include only Bronze Age catastrophes and, apart from papers concerned with present-day scientific findings which could throw light on past events, to exclude from the formal programme topics which were not clearly related to the subject of the conference.
On the other hand, the meaning of Bronze Age was interpreted loosely, partly for reasons which, since not all who read these Proceedings are likely to be particularly knowledgeable about archaeology, may need a brief explanation. The term refers, of course, to a time characterised by the use of bronze weapons and tools, but it was not an all-or-nothing situation: iron was used, albeit rarely, in the Bronze Age, and bronze continued to be used in the Iron Age.
In any case, metals (of whatever type) were far from common, so the different levels at particular locations are generally classified on some other basis, e.g. style of pottery, enabling correlations to be attempted between different sites, but not without some element of subjectivity. Also, the introduction of a new metal-working technique has to start somewhere, and it could take a long time for it to spread to a far-off region, or to be developed independently. Hence, the Bronze Age undoubtedly started and finished at different times in different places. For example, as we have already noted, the Early Bronze Age in the Middle East overlapped to a considerable extent with the Neolithic in north-western Europe. Furthermore, it is generally believed that the Iron Age in some locations did not begin for several centuries after the end of the Bronze Age, the intervening period being a Dark Age, thus complicating the picture still further. So, a broad view was taken by the organisers of the Second Cambridge Conference as to the period covered by the term Bronze Age and, in consequence, it should be understood that it was concerned with events between about 3500 BC and 500 BC.
2. The Proceedings
The first paper in the Proceedings is based on the keynote address by science journalist Robert Matthews. In this, Matthews makes two main points: (1) that observations made in the distant past may be far more accurate than we generally assume; and (2) that, because of the dangers from asteroids and comets, the Earth is not, and never has been, a safe place to live. He concludes with a quotation from George Santayana: 'Those who do not remember the past are condemned to relive it.'
Then follows a series of papers by astronomers concerned with those hazards from space. Firstly, Mark Bailey reviews recent advances in our knowledge of Near-Earth objects, some of which originated in the cometary regions of the Solar System and some in the main asteroid belt. Calculations indicate that giant comets are likely to come into the inner Solar System and break up every 0.1 to 1 million years. Bailey points out that it is now sometimes difficult to make a clear distinction between asteroids and comets. Regardless of that, they undoubtedly pose a threat, and some may have struck the Earth in the astronomically-recent past.
Bill Napier then assembles data from a variety of sources to present a picture of the current interactions between the Earth and its cosmic environment. In his view, the Taurid/Encke complex of interplanetary material has been a regular and occasionally conspicuous hazard over the past 12,000 years or more. This has resulted in impacts such as that which devastated the Tunguska region of Siberia in 1908; in an occasional contamination of the stratosphere by cometary dust, leading to freezing episodes which may have lasted decades; and in small-body impacts into an ocean, causing catastrophic flooding of coastal areas.
After these two papers comes one from Duncan Steel which is more speculative, although based on the same astronomical data and interpretations. Steel makes the intriguing suggestion that the construction around 3500 BC of the Great Cursus near Stonehenge, and that around 3100 BC of the first stage of Stonehenge itself, were intended as predictors of catastrophes, since these were the approximate times when the orbit of the giant proto-Encke comet intersected that of the Earth.
Finally, for this section, Gerrit Verschuur takes both a scientific and a philosophical view of the Earth's place in space. Impacts have been the rule rather than the exception, and will be in the future. The problem of humankind is that hope prevents us from seeing that the cosmic events which have destroyed civilisations in the past will continue to do so, unless we take preventative action.
The next and largest group of papers are concerned with archaeology, geology and climatology. To start this section, Bruce Masse attempts to re-evaluate events on Earth in the light of estimates made by astronomers of the rates of impact of asteroids and comets.. On the assumption that 20-30 impacts causing at least local catastrophes are likely to have occurred in the past 6000 years, he examines literary traditions, together with archaeological and palaeo-environmental data, to see if any previously unknown Bronze Age catastrophes can be identified. The most significant one appears to be a cometary impact in the ocean around 2800 BC, which released almost a million megatons of energy, causing devastation on a global scale.
After this come three papers which are concerned, at least in part, with happenings around the time of Mandelkehr's supposed 2300 BC catastrophic event, close to the end of the Early Bronze Age in the Middle East. Firstly, Marie-Agnès Courty presents new archaeological evidence of a dust layer and burnt surface horizon apparently caused by an air blast in northern Syria around 2350 BC. A previous hypothesis involving a local volcanic eruption has now been rejected, with a cosmic catastrophe appearing more consistent with the evidence, but whether such an impact event actually took place at the time has still to be established. Regardless of that, Courty stresses the importance of high temporal resolution investigations in the assessment of causal relationships between natural catastrophes and societal collapse.
Evidence for an adverse climate change in Ireland at about the same time, and on several other occasions, is then given by Mike Baillie. Narrowest-ring events in Irish oak chronologies corresponding to 2345 BC, 1628 BC and 1159 BC line up with similar events in other tree-ring chronologies and also large acidities in Greenland ice records. They also correspond to the approximate ages of the Hekla 4, Santorini and Hekla 3 volcanic eruptions, respectively. However, the narrowest-ring events are imposed on pre-existing climatic downturns, which, as with similar events around 207 BC and 540 AD, suggests a scenario of stratospheric dust loading and bombardments from space, the latter triggering or at least augmenting the volcanic eruptions.
Benny Peiser then summarises a survey he has made of around 500 reports of late 3rd millennium BC civilisation collapse and climate change, which shows a significant clustering around 2300 BC. Most sites in Europe, the Middle East, India and China where civilisation collapsed at this time show clear signs of natural disasters and/or rapid abandonment, whilst around the world there is strong evidence of water-level and vegetation changes, glacier and desert expansion, seismic activity, floods and extinctions of animal species. He concludes that only extraterrestrial bodies acting on terrestrial systems could produce the range of glaciological, geological and archaeological features reported.
The next group of papers is concerned with events which are slightly more recent, occurring around the time certain Late Bronze Age cultures came to an end. Firstly, Amos Nur argues that large earthquakes are likely to have contributed to the physical and political collapse of Late Bronze Age civilisations around the eastern Mediterranean. It is known that, every few centuries, massive earthquakes occur in bursts that sweep across about 1000 km of the eastern Mediterranean over a time-scale of approximately 50 years. In Nur's scenario, the burst at the end of the Late Bronze Age probably began between 1225-1175 BC, and made urban centres vulnerable to opportunist military attacks.
Then, Lars Franzén and Thomas Larsson present evidence from sites in Tunisia and Sweden showing that a major atmospheric cooling event, accompanied by excessive precipitation, which led to flooding, occurred around 1000 BC. Other sources indicate that the event was sudden and widespread, and the finding of small glassy spherules points to a possible impact origin. Franzén and Larsson suggest that an asteroid or comet of diameter in the range 0.5-5 km may have landed in the eastern Atlantic around 1000 BC, affecting in particular Europe, North Africa and the Middle East.
After this, Bas van Geel and colleagues show that a sharp rise in the 14C content of the atmosphere towards the end of the Bronze Age in north-western Europe, around 850 BC, was accompanied by a rapid transition from a relatively warm and dry climate to one which was cooler and wetter. They suggest that a reduced sunspot activity at that time allowed more high-energy galactic cosmic rays to reach the top of the atmosphere, leading to an increased production of 14C cloudiness and precipitation.
The final paper in the section on archaeology, geology and climatology is by Euan MacKie, who begins by warning that astronomers will have to produce clear evidence of comet swarms or the likelihood of large impacts at specific dates before most archaeologists will be willing to re-examine their data with this in mind. He then briefly suggests some examples of instances where such a re-examination might be productive, including two around the end of the Bronze Age in north-western Europe. One of these concerns a site ten miles west of Glasgow, where there are two phases of "cup and ring" rock carvings, the first perhaps from the latter part of the 3rd millennium BC, and the other probably from the 6th or 7th century BC. According to Victor Clube and Bill Napier, these could be representations of comets, but that suggestion is not currently being taken seriously by archaeologists. The other example concerns the vitrified forts of Scotland, dating from the period after 800 BC, whose timber-framed construction might have been intended as a protection against earthquakes.
The Proceedings are then brought to a close by five papers on the subject of history and culture. In the first paper, Gunnar Heinsohn considers the origins of kingship, priesthood and blood sacrifice in the Early Bronze Age. Nicolas-Antoine Boulanger, in the eighteenth century, believed they were reactions to major catastrophes taking place at the time, but that view has been disregarded almost ever since. However, in the light of increased knowledge about cosmic events, Heinsohn argues that Boulanger was correct after all. Re-enacting catastrophic events as rituals involving blood sacrifice would have had a therapeutic effect on traumatised survivors. Significantly, according to Heinsohn, there was a gradual abandonment of blood sacrifice in the Iron Age, when cosmic catastrophes were much rarer events than they had been in the Bronze Age.
Similarly in the next paper, David Pankenier suggests that, contrary to what has generally been supposed, legends and rituals from Bronze Age China may reflect actual events. In particular, around the time of the transition from the Xia to the Shang dynasty in the middle of the second millennium BC, there is a story of ten suns appearing in the sky and then, a few years later, of five planets criss-crossing, and stars falling like rain, after which there was an earthquake and then a drought. It would not be difficult to see this as an indication of the appearance of multiple comets in the sky, and impact-induced catastrophes. The same or a different cometary catastrophe could also form the basis for the legend of the battles between the wicked Chi You and the Yellow Emperor, which featured in ritual games.
Finally come three papers which, on the assumption that major catastrophes were indeed a feature of the Bronze Age and the first few centuries of the first millennium BC (whatever Age one wishes to call this latter period at particular locations), consider how humankind reacted when more peaceful times came along.
Firstly, William Mullen describes how the Milesian School of pre-Socratic philosophers in the sixth century BC set out to explain terrifying phenomena such as thunder, lightning, earthquakes and eclipses in terms of the same processes which it used to explain the orderly arrangement of the Earth and the heavens, thus moving away from the old view which associated them with the unpredictable activities of the Olympian gods. World-destructions could occur, but only in cycles which stretched over vast periods of time. Mullen suggests that the hidden agenda may have been a desire to reassure the population that they were now safe from the cosmic catastrophes which had occurred in the past.
In similar fashion, Irving Wolfe then argues that a cultural crisis occurred in the sixth century BC, with the appearance of new religions, new philosophies, new art forms, new types of games and new forms of social organisation, all of which were very different from what had existed previously. In many ways, these laid the foundations for the cultural characteristics of our modern age. According to Wolfe, the cost has been that, ever since the middle of the first millennium BC, humankind has been suffering from a collective form of Post-Traumatic Stress Disorder, denying not only past catastrophes, but also the possibility of future ones.
The denial of past and future cosmic catastrophes was certainly a feature of the influential philosophy of Aristotle, and has been a characteristic feature of scientific thought over the past few centuries. However, in the concluding paper of the Proceedings, Victor Clube argues that the situation in between was somewhat different. The relatively tranquil period in the middle of the first millennium BC did not last for long, and further episodes of cosmic bombardment conditioned people once again to believe that the world might come to an end in this way. Clube suggests that this provides strong support for coherent rather than stochastic catastrophism, because frequent small-scale events would keep the issues in people's minds, which would not be the case if there were vast periods of time between impacts. According to Chinese astronomical records, there have been seven peaks of fireball activity in the past 2000 years, at times which indicate an association with the Taurid/Encke complex. However, the past two centuries have been a quiet period and, because of the influence of Lyell and Darwin (who established the gradualistic paradigm, largely for philosophical reasons), and of Newton (who played down the threat from space on religious grounds), the future seemed secure. We now know otherwise but, in contrast to previous generations, who could only hope and/or pray, we may soon have the capability for defending ourselves. However, Clube warns that the prospect of safeguarding the future of civilisation is not being helped by those who cling to gradualistic, Earth-centred views, or by those who adopt what he sees as erroneous forms of catastrophism. To produce the best answer, we must fully understand the problem.
We are grateful to Alasdair Beal, Birgit Liesching, Bill Napier and David Roth for their help in preparing papers for these Proceedings.