1859 + 150: Time depth and process.

Renfrew, Colin

In a single year two of the fundamental principles for the study of antiquity were established: chronology and process. Both have been elaborated and re-visited since: chronology most significantly 90 years later in 1949 with the development of radiocarbon dating by Willard Libby. That these two foundations should be established in the ambit of a single year--1859--is remarkable, and worthy of celebration.

With the Antiquity of Man, the study of prehistory became at last possible. So 'the stone that shattered the time barrier' is a crucial piece of evidence. It is splendid that Gamble and Kruszynski have been able to locate the very handaxe that Prestwich and Evans were able to photograph in situ in the gravel pit at St Acheul. This is a story worth telling, and an artefact worth exhibiting. But is there not one strand in the story that is here undervalued? Where was Boucher de Perthes? It was he who had recognised the importance of the gravel deposits and who had published his findings. It was he who had taken Evans and Prestwich and the others on a guided tour of the Abbeville pits that very day, followed by 'a most sumptuous dejeuner a la fourchette'. Perhaps he should share rather more of the congratulations with the British grandees who had come to visit his sites.

The huge expanse of time which the discoveries at Abbeville and St Acheul and indeed Hoxne made possible allowed also a considerable time depth for later periods, and it was Lubbock himself who invented the terras 'Palaeolithic' and 'Neolithic' in order to begin to subdivide this great time depth. So it is indeed of great interest that Tim Murray should have re-located the illustrations which Lubbock himself commissioned, although he did not employ them to illustrate his Pre-historic rimes (Lubbock 1865). It is interesting that he used them to accompany the artefacts in the private museum at his house in Kent. They stand at the head of the series of well-informed works of reconstruction with which subsequent artists have sought to bring to life the early past.

Darwin's series of principles, outlined in On the origin of species, were even more momentous. For they set the past of biology and palaeontology (and by implication of much more besides) in a context where they could be approached by the study and understanding of process. In Darwin's specific case, vast in its scope as it was, that process was natural selection. But we can situate that very powerful general principle in the context of yet more widely applicable concepts. For we see here the echo of an earlier debate that set creationism or catastrophism against process as the key agency of long-term change, and within which the principle of uniformitarianism was developed. As James Hutton in his Theory of the Earth (Hutton 1785) had written: 'No processes are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principles' (quoted from Daniel 1950: 37). So it was that Charles Lyell gave as the subtitle to his Principles of geology (1830-1833): 'An attempt to explain the former changes of the Earth's surface by reference to causes now in operation'. Darwin's theory of natural selection is in a sense a special case of the unformitarian principle developed by these pioneering geologists. And the general approach has even wider implications, for this view of process is clearly related to the cosmological principle--'On large spatial scales, the Universe is homogeneous and isotropic'--which has been current since the time of Copernicus. In a sense cosmology, geology, and Darwinian biology share a generalist and uniformitarian view of process, to be contrasted with the catastrophist or 'diluvial' position of the creationists, then and now. Darwin's interest in earthworms as the agency of slow change in soil formation is another example of this approach, this time on the very local scale. It led him to some interesting dabblings in archaeological excavation, as Chris Evans reviews here.

Posterity has been good to Darwin. For molecular genetics has given a very precise mechanism for the inception of variability, which is one of the bases for the theory of evolution. Evolutionary genetics now underlies our understanding of Darwinian evolution, so that the structure of DNA gives the clue as to how these things work in our world. Yet these elucidations also present challenges to the historian and to the archaeologist. For when it comes to human culture or cultures, different mechanisms are at work. During the speciation phase (Renfrew 2006, 2007: 94) it cannot be doubted that changes in the genotype, that is to say changes in the structure of the hominin DNA, were a fundamental part of the evolutionary process. But since the out-of-Africa dispersal of our species, some 60 000 years ago, the genotype, i.e. the DNA sequence, has not changed very fundamentally. Different cultures and civilisations are not to be distinguished one from another simply by comparing the DNA of their populations. Darwinian evolution does not seem to have very much to offer here.

So this I take to be part of the continuing legacy of Darwin. He situated the emergence of humankind, The descent of Man (Darwin 1871) as he was to term it 12 years later, within the context of the evolution of species, seeing this as part of a gradualist and uniformitarian process which rendered creationism unnecessary. He opened the way towards the evolutionary genetics which today, with the help of DNA studies, allows us to understand the mechanisms in much greater detail. But as we better understand those mechanisms, we see that these are not very relevant to the changes taking place in the subsequent tectonic phase of human development (Renfrew 2006, 2007: 101). Although some scholars have begun to puzzle out the processes which underlie cultural evolution (for example Shennan 2003), we are only now coming to terms with the issue.

The legacy of 1859 was a new view of time depth and of process. We have learnt, with the aid of radiometric methods, to control chronology rather well. But the analysis of process as a key to the understanding of human history, even with the aid of molecular genetics, remains a challenge for the future.

References

DANIEL, G.E. 1950. A hundred years of archaeology. London: Duckworth.

DARWIN, C. 1859. On the origin of species by means of natural selection. London: John Murray.

--1871. The descent of Man, and selection in relation to sex. London: John Murray. HUTTON, J. 1785. Theory of the Earth.

LUBBOCK, J. 1865. Pre-historic times as illustrated by ancient remains and the manners and customs of modern savages. London: Williams & Norgate.

LYELL, C. 1830-33. Principles of geology. London: John Murray.

RENFREW, C. 2006. Becoming human: the archaeological challenge. Proceedings of the British Academy 139: 217-38.

--2007. Prehistory, the making of the human mind. London: Weidenfeld & Nicolson.

SHENNAN, S. 2003. Genes, memes and human history: Darwinian archaeology and cultural evolution. London: Thames & Hudson.

Colin Renfrew, McDonald Institute for Archaeological Research, University of Cambridge, Downing Street, Cambridge, CB2 3ER, UK