Abstract
In 1919, Alfred North Whitehead gave a series of lectures subsequently published as the Concept of Nature; in those lectures, he provocatively called the Great Pyramid at Giza an ’event’ (not simply a building, or an object); Whitehead‘s intention was to argue against a materialist theory of nature, by which he meant an atomistic, object-centred theory rather than one which foregrounded the ’passage of nature’ as he called it – the fact that the world is in a constant state of flux or becoming, rather than one composed of static elements. Whitehead was openly influenced by the french philosopher  Henri Bergson and both thinkers were of course important to Deleuze. In this paper, I want to draw on the ideas of these philosophers to explore the relations between object and event as they are articulated in our understanding of the archaeological record and in particular, suggest that as archaeologists, we are not simply digging up the residues of events but digging up actual events. To appreciate this point however, means re-thinking what we mean by terms such as object and event and also enriching other concepts which we usually take for granted, especially the concept of ’assemblage‘. At the heart of this problem is the relation between time and materiality and understanding the complexities of writing histories from/ of things.

There are two related problems I want to examine in this short paper. The first concerns the distinction between objects and events and how that affects our understanding of the archaeological record. I suggest we need a concept that captures the continuity between object and event rather than a dichotomy. In this regard, the notion of assemblage is more apt – but one which also brings its own problems, chiefly its pre-existing meaning in contemporary archaeological discourse. The second issue concerns the nature of history in relation to the object/event continuum; the question here is: to what extent do assemblages preserve a memory of their own history? Or, what is the ontology of residuality? These are difficult issues – and perhaps impossible to do justice in a 20 minute talk, but I will try nonetheless.

Part 1. Assemblages
There have been many ways to draw a line between the contemporary archaeological record and the past to which it refers or from which it originated: Lewis Binford‘s statics vs. dynamics, Michael Schiffer‘s archaeological vs. systemic context, or Warren DeBoer‘s dead vs. living assemblages. What they all share in common is the idea that the archaeological record is composed of the material residues of events and processes; the events have long ceased to exist but at least some of the objects involved in those events have survived. The danger comes when one slips into the language of separating object and event so that the archaeological record appears ‚eventless‘; it clearly isn‘t, simply because ruins and artifacts are always caught up in events, not least through the activities of archaeologists themselves. Approaches like Schiffer‘s transformational theory of the archaeological record recognizes more than the others that the issue is not that the archaeological record is eventless, rather that its elements (i.e. objects) are not bound to single events or processes but are event-transgressive: they take part in multiple events. However, even in Schiffer‘s model there remains a distinction between object and event insofar as this transformational process has limits: an origin (e.g. an object‘s primary or original context) and an end (the archaeological record as encountered by the archaeologist). These limits in  a sense, guarantee the essential stability of an object, that it remains what it is, independent of the successive events through which it traverses and the modifications which may affect it.

But the fact is, there is no beginning or end – just a constant process of transformation. The ‚origin‘ of any object is just another transformation of matter through whatever agencies – a natural stone being formed by geological and geomorphological processes is continuous with that stone being flaked into an axe, being re-sharpened, being broken and then re-worked, and so on.

By taking a continuous perspective on objects, one sees of course that the object itself changes in the context of these events, and one should question whether it is the same object at all. What it shows is that object and event are not absolutely distinct but are mutually constitutive; it suggests that what we are dealing with are processes of materialization, de-materialization and re-materialization on a single ontological plane, not two separate ontological planes, of events and objects.

Many of these ideas one can see anticipated in Alfred North Whitehead‘s discussion of an event ontology. First presented in his lectures of 1919 on the Concept of Nature and later elaborated in his major work Process and Reality, Whitehead argued against a materialist theory of nature, by which he meant an atomistic, object-centred theory rather than one which foregrounded the ’passage of nature’ as he called it – the fact that the world is in a constant state of flux or becoming, rather than one composed of static elements. He talked about the Great Pyramid of Giza as an event, but gave a more detailed illustration of his ideas through another Egyptian monument, Cleopatra‘s needle, which now lies on the Embankment of the River Thames in London.

Whitehead saw this obelisk as a continual happening or occurence; not only has it moved location – first from Heliopolis to Alexandria in 12 BC, then from Alexandria to London in 1878, it is constantly changing on a micro-scale in terms of accumulated soot and grime and the erosion of surface particles and on atomic scales in terms of the interchange of molecules. It is perceived as an object however because the multiple occurrences which pertain to it, cohere into what he later defined as a society. By the term ‚society‘, Whitehead meant any enduring object – a self-sustaining collection of events which share a common history. In terms of the conventional distinction between objects and events then, an object is simply an enduring collection of events bound together while an event is an ephemeral, unbound occurence.

The event-like nature of objects in terms of this material fluidity is much more apparent if one thinks of them as assemblages – and by implication, thinks of assemblages as object-events. The distinction between object and assemblage is not absolute but merely a matter of degree; one might think of them as ideal points on a grid defined by qualities of coherence and persistance – that is, how impermeable they are to material re-configuration on the one hand and how enduring they are on the other. An artifact like a pottery vessel may have a short use-life before it is broken but it is difficult to modify without completely changing what it is; a building on the other hand can be repaired, fixed, altered and stand for centuries yet still function as a building. The building is an example of what I mean by an assemblage.

An assemblage is something more like a machine or an organism than the conventional idea of assemblage in archaeology. An organization of matter which operates as an autonomous or semi-autonomous entity but one which permits flows of material in and out. The conventional concept of assemblage in archaeology is vague but generally refers to a group of finds – artifacts, animal bones etc. – which are related by context. The definition of context can be variable, from a single feature to a whole site; moreover, the term may apply to all material from such a context or just a specific subset, e.g. pottery. Clearly this notion of assemblage bears little relation to the term as I use it here; the assemblages I am thinking about are more like our archaeological concepts of structures, sites or landscapes. One might think of an archaeological site or indeed a landscape as the corpse of an organism or one huge, defunct machine. One might think of excavation as autopsy. Such assemblages obviously vary in both their openess and complexity.

It is no coincidence that such descriptions evoke an older theoretical language, that of systems theory and cybernetics. They also resonate with many ideas circulating in contemporary theory today –Deleuze and Guatarri‘s concept of strata, Bruno Latour‘s notion of a collective, or Manuel De Landa‘s idea of the assemblage (after Deleuze), which themselves sometimes explicitly reference these earlier ideas of cybernetics. It may seem ironic that today, one should be invoking systems theory as an influence, but there is a fundamental difference between the systems theory employed in archaeology of the 1970s and that used here. In the 1970s, cultures were systems, while ideologies or technologies were sub-systems. These cultural systems are abstractions, reifications of social phenomena; the systems I am talking about are concrete, material assemblages made of stone and earth, flesh and bone.

Part 2. Archives
While the concept of assemblage may be viable and resonate with other concepts in contemporary social theory, there is one significant difference with archaeological assemblages: they are the residual. As residual, they exist like memories, those parts of contemporary assemblages which are the preserved traces of a former existence, a fomer mode of material organization. This is a point which has also been picked up by Laurent Olivier in his recent book The Dark Abyss of Time. These assemblages exist in the present, but are buried – both physically and metaphorically. Herein of course lies the origins of two fundamentaal concepts in archaeology: stratigraphy and palimpsest. These terms describe the manner in which their residual nature is articulated within contemporary assemblages. It is thus an ontology of residuality that I want to explore next.

Stratigraphy is of course one of the most well-known and basic concepts in archaeology and appears in every archaeological textbook; theoretically however, it has received almost no attention if one excludes methodological debate such as that between geoarchaeologists and the Harris school of stratigraphy. With palimpsest, the situation is almost reversed. In landscape archaeology the concept of palimpsest has a long pedigree but it is hardly a core concept in the discipline; theoretically it entered archaeology in 1981 with the simultaneous publication of three papers by Lews Binford, Robert Foley and Geoff Bailey. All three archaeologists drew attention to the fact that the archaeological record is almost always a palimpsest of residues from multiple events, while one of them – Bailey – went on to develop a whole theory from this observation called time perspectivism.

The idea of a palimpsest refers of course to the ancient practice of writing, erasing and re-writing on the same surface – originally wax tablets but later medieval manuscripts. The sense in which Binford and most archaeologists use it however is somewhat different – more like superposition without erasure – but also without preservation of the sequence of deposition. Like writing over a tablet without erasing the previous text. As such, a palimpsest is in effect, the antithesis of stratigraphy: superposition without sequence.

What I find a little odd in these discussions of palimpsests however is that there is no discussion about the relationship between palimpsests and stratigraphy. The focus is rather on distinguishing the archaeological record as a palimpsest from a living context; but palimpsests are a fundamental feature of material existence whether one is talking about the archaeological record or an ethnographic context. It is admittedly a matter of degree and archaeologists need to reflect on the temporal resolution of their data, but the over-emphasis given by time perspectivism to short versus long-term scales obscures what is surely a more important issue: the preservation or memory of sequence. If palimpsests imply a loss of memory, stratigraphy is the inverse – the preservation of a sequence of object-events or assemblages, of material formations. In a sense, the concepts of stratigraphy and palimpsests are virtual points at either end of a continuum: on the one hand, total preservation of sequence, as every materialization in the past had been preserved, and on the other, total erasure of each materialization by a succeeding object-event.

Both poles in their pure form however, are an impossibility – in the first, matter would have to constantly increase whereas in actuality, any organization of matter is simultaneously a de- and re-organization of previously existing matter. This is given concrete expression in the recognition that real stratigraphic sequences are not just composed of the superposition of matter but also the subtraction or erasure of matter in the form of cuts and erosion surfaces. Concommitantly however, erasure is not absolute but relative to a particular locale: any cut or truncation does not destroy matter, it merely moves it somewhere else. This is why the pure palimpsest is equally an impossibility – if all matter was erased and each new deposit started anew, there would be no history, no time. Rather than seeing this as a process of inscription and erasure – which it is relatively speaking, relative to any paricular locale – it is more fruitful to see it as a process of de-organizing and re-organizing of matter. As archaeologists however, we do not see this process – we simply observe its effects at a locale level.

Thus in actuality, the archaeological record (and material reality in general) lies between these virtual extremes of stratigraphy and palimpsests, which always remain nothing more than virtual. If we articulate this idea with that of the archaeological record in terms of de-materialization and re-materialization, then it is always a question of degrees of de- and re-materialization; as such, the archaeological record is an archive of this process.

The question is fundamentally about change and the extent to which changes in material organization preserve traces or memories of previous organizations. This is why the concept of the archaeological archive or record is so apt – it encapsulates this tension between the virtual poles of stratigraphy and palimpsest. If the notion of the assemblage discussed earlier foregrounds the temporality of objects as events, the notion of the archive or record foregrounds the preservation of material changes within an assemblage – it presents us with the idea of matter auto-archiving its own past. This is not a new idea – Lyell used much the same metaphors in the 19th century when talking about the geological record.

The question remains – is this archiving process random or not? Is what occurs in the archaeological record simply a product of chance or something else? Conventionally, preservation is considered to be largely about natural processes of decay, but of course there are mutliple agencies involved in this archive process and they are not necessarily related. Material assemblages offer various resistances to their environment which influence rates of decay – and these resistances are not so much determined by any intrinic properties in the assemblages or elements themselves as in their relation to this environment, which is both social as well as natural. In short, entropy is a social as well as a natural phenomena. Let me offer some analogies I have used on previous occasions to illustrate this point.

Consider as the first, a book collection. How does one characterize this assemblage in relation to residuality? One can re-arrange the order of books on the shelf tomorrow and there will be no trace of the former order at all. If I take away some books that I am tired of, the same effect accrues. In short, subsequent events have completely erased antecedent ones and it is as if they never existed. This is an anti-historical process in the sense that it creates no history in the collection itself; materially speaking, such projects have the effect of reversing time, and they are extremely common. Materially speaking, reversibility is not only possible but ubiquitous in social phenomena – one only has to think about the material organization implicated in everyday activities one is involved in, to find more examples. Elements may survive - e.g. books, shelves, but the particular organization does not. Such an assemblage lies close to the palimpsest end of the spectrum.

Other assemblages however offer a contrast; as the second example, consider a traffic system, especially as regards which side of the road one drives on. To change this – for example to make the cars drive on the right hand side in Britain as almost everywhere else in Europe would be an enormous task; the complexity of the material connections accumulated over time have created massive inertia in this respect such that to reverse it or to re-organize it, would involve major disruption. But it is still possible. This is not just about changing the attitude of the driver – indeed this is perhaps one of the easier elements to change – but the material infrastructure (cars, signage, roads). In short, there is an inherently greater irreversibility built into a traffic system than a book collection, even if both are, potentially reversible. The traffic system presents us with a more stratifiable assemblage than the book collection.

The importance of characterizing assemblages through this quality of reversibility/irreversibility is to highlight the critical factor in those assemblages that leave residues in the archaeological record. Archaeological assemblages are quite emphatically tied to the degree of reversibility in material organization, which in turn, directly effects residuality. Thus on the one hand, change occurs much more readily in assemblages with greater reversibility (e.g. the book collection); on the other, such changes also leave less material residues. Conversely, the assemblages, which have greater irreversibility and change with difficulty (e.g. the traffic system), tend to leave much more material traces. This property is largely related to the extent an element or object within an assemblage is constructed specifically to fit that assemblage – that is, how self-sustaining or autonomous an assemblage is. Books can be re-ordered in multiple ways and their materiality is not intrinsically tied to any particular system; a car on the other hand is built to operate quite specifically with left or right-hand side traffic systems and becomes anomalous if not defunct once the assemblage is changed. Either it is taken apart and re-assembled or it is simply discarded – and which of these fates it has, is also a question of reversibility since a car, although an object from the perspective of a traffic system, is also an assemblage from the perspective of a mechanic.

Talking about assemblages in terms of entropy, resistances to change, to being de- or re-materialized, means in a sense that understanding the archaeological record is about grasping its probabilistic nature with regard to the process of materialization. We deal with actualities, with real residues of past assemblages, but what they reveal to us is not some kind of mirror existence, comparable to our own present but rather a latent materiality, one whose forces and powers are potential rather than actual. As archaeologists, I would suggest that we are exploring potential or virtual materialities, yet ones which were (and are) nonetheless real; the real incorporates both the actual and virtual, it is not opposed to the virtual. These virtual materialities are the fields or forces that bind and disperse assemblages.

This brings us back full circle to  Whitehead. Assemblages, or what Whitehead called ‚societies‘ are the actualization of a field of potentialities. Whitehead referred to these potentialities as eternal objects. It is these eternal objects which enable repetition and thus order in the universe. Actual objects are events because they are the determination or actualization of potentialities. The eternal objects are somewhat like Deleuze‘s Body without Organs, a virtual materiality. Curiously the only archaeologist I am aware of that has has ever cited Whitehead is Lewis Binford. In a paper published in 1982, Binford enigmatically drew on Whitehead to suggest that these eternal objects were critical to understanding the archaeological record. For Binford, Whitehead‘s eternal objects acted as frames of reference. Bur Whitehead‘s eternal objects were not just epistemological frames of reference but also the ontological parameters of reality– they defined the limits of the real. What the archaeological record offers us is a glimpse into how one domain of reality – assemblages of humans and other things - preserves its own past within itself. But the past itself, remains virtual, never actual. The actual remains as they exist for us in the present, articulate a part of virtual reality which may be otherwise hidden and in doing so, adds to our understanding of the limits of the real. More specifically, it contrbutes to a history of reality and reminds us that reality is a historical process, of becoming rather than being.

A lot has been left unsaid here; questions about how one defines reversibility in archaeological assemblages, in practical, even quantifiable ways; also questions about what kind of narratives this archaeology of the virtual might produce, and how it differs from conventional narratives. I cannot pretend to have any answers, and maybe the particular path taken in this talk will lead to stony ground. For all that, the basic line of questioning is I believe not only valid, but vitally important. What is the ontological status of the stuff we, as archaeologists, engage with? For it seems to me that this is a question which has been too easily ignored or glossed over, especially when it comes to theoretical discourse where the emphasis has been on commonalities between archaeology and other social and humanistic disciplines, without due attention to the empirical differences. Nowhere is this more apparent than in the concept of material culture, which conceals a multiplicity of ontologies, many of which are simply unsustainable in relation to the archaeological operation. It is time to critically review the concepts we routinely use in archaeology in relation to the ontology of our evidence.