Essay by Philip M. Williams

Stonehenge, Avebury, Silbury Hill
A Meditation on Function

Stephen Jay Gould, in The Structure of Evolutionary Theory, reiterates the following.
As a general structural principal, applicable across a full range of natural phenomena, from cosmology to human social organization, complex systems can usually collapse catastrophically, whereas the construction of such functional intricacy can only occur by sequential accumulation - a pattern I have called "the great asymmetry" (Gould, 2002,p 1145).

Stonehenge, Avebury, and Silbury Hill fit the pattern of great asymmetry. Each site reveals a complex social organization. Each site collapse was catastrophic, and remains a source of no little speculation. Their structural intricacy occurred only because of sequential accumulation. An almanac as a function was not lost, although Stonehenge was lost. The art and science of estimating time and materials in moving large amounts of earth was not lost, although Silbury Hill was completed. The skills of moving and erecting large unshaped stones were not lost although Avebury fell into disuse.

Christopher Smith, in Late Stone Age Hunters of the British Isles issues a stern warning when one comments on the evidence in an archaeological inquiry.

The evidence must be examined rigorously, and as objectively as possible, while the basic subjectivity of the inquiry is acknowledged. (Smith, p 8)

Following in Professor Smith's footsteps, I aver that I'm an old man who spent much of his middle age buying building sites, building single family houses out of wood, and selling them. I thus have a bias, that of a builder. It could be useful in speculation of function. I cannot escape it.

Silbury Hill is a work-in-progress. Its most unusual aspect is that it appears to have been completed. Avebury is a work-in-progress. We do not know if there was an endpoint, or if there was a need of an endpoint. Stonehenge was built-to-order. All three projects illustrate that construction in the round gives amplitude for expansion without diminishing the building's function. This is graphically illustrated in Julian Richards' Stonehenge. As evidenced by postholes, Woodhenge and Durrington Walls both increased their diameters to accommodate a larger interior population.

One should note that light was not optimized by enlarging the roof opening, unless the building's function was mud wrestling during periods of rain. All similarly large structures had multiple "doorways", which we now call windows, since we, and surely them, block them up halfway and thus make a distinction. During summer heat, cooling breezes are allowed to sweep through doorways, or more likely windows. They also give light. The upper half could be shut, by a shutter, or by a skin. A two or three foot hurdle, or equivalent in-fill, makes the opening more handy to secure, while still optimizing valuable sunlight.

Any building of Durrington Walls' size and scope indicates sophistication of construction, and an increasingly complex social structure. The enlarged society need not mandate an enlarged construction crew. The new larger structure is built outside of the existing building. It is piecemeal work, one post at a time, placed a given distance from its interior partner post. The chaos without does not upset the tranquility within. That is the advantage of expanding large, round, ground floor buildings. The larger roof is built atop the smaller roof. The interior roof gives footing for the exterior roof, again minimizing disturbance below. There is no need to erect scaffolding, although at some point the deteriorating roofing material might be removed. It might be at such time when the client is considering roof replacement that it is decided to expand the project. How well these buildings fit the conceptualization of sequential accumulation.

Woodhenge, Durrington Walls, and Stonehenge were built-to-order. "We want such and such. Can you do it? How long will take?" There is still a requirement of creativity, as well as technical skill, in an order-built project. Brunelleschi in Florence and Michelangelo in Rome built domes to order. Their work is only slightly less impressive than the order-built structure of Stonehenge. That builder had the problem of procurement and transportation of exotic materials. Once any part of material arrived he had to cope with the problem of foundational stability. Stability is fundamental in any building project. It is critical to Stonehenge, which rests its large masses upon small footprints.

Another trial was measuring and cutting. Each posthole was custom made, and was measured to a custom depth. The stability of the ground was tested and approved by a soils man. The soils man, or men, most likely executed the digging. Too deep and one would have to add fill, the compression of which would result in an uneven top plate. The compression factor of a large weight falling a given distance had to be estimated. The hole, and stone itself, would have had to be measured before, during, and after the tenon was cut. Therefore the client's order included a predetermined top surface of upper plate height. This finished height was given to the builder long before the material to be fabricated was brought to the site. Otherwise, how could he select potential candidates for the finished project?

Evidence of sequential evolution remains at the site of Stonehenge to this day. Earlier forms were of wood. This is interesting. Scientific advances were being made by modifying and improving the manufacture of scientific instruments to give increased precision of measurement and observation. Stonehenge is not magic. It is merely the advancement of science, although many people think that there is an element of magic in any advancement of science.

One quails at the prospect of even describing the technical subtleties of dropping large stones into pre-dug holes with such precision that equally large stones are fitted at their summit in mortise and tenon and tongue and grove exactitude. Sequential evolution in an individual's life is called experience. Experience alone is helpful and necessary in completing the above, but other elements are needed. Many youths are experienced at playing soccer football. Some become expert. Even fewer are immortalized because of their ability to focus, coordinate, and time their moves during periods of extreme competitive pressure. One says that they are "in the zone", and that they do the impossible.

Although they may appear identical, each stone is unique. That is due to the nature of the material itself, which is not uniform in density. Additionally, each is roughly cut to an idealized shape. With the exception of the top surface of the upper plate, there was no value added to precise cutting to a block that was intrinsically disuniform. One may take away from the top of a long stone already in the hole, but how does one add to it? With its massive weight centered in such a small footprint, it is impossible to turn, twist, or otherwise adjust the position of the stone once the stone's weight is transferred from its length to its end.

The ancients knew better than us that all of the stone's weight had to be taken off the footprint in order to change its position. Otherwise the moving action would eat into the hole. That reduces stability and destroys the overall height calculation. The stone must needs be removed from its hole and the entire operation would have to be repeated. The significance of that reality was the source of pressure on the hand and mind of the master mover. He had to identify the individual character of the stone, identify what and where, the final slight pressure of the hand would start the final move and make that push be smooth and precise, without a twitch of uncertainty.

As an analogy, and only as an analogy, it is instructive to view the launching of a large ship that is built upon its ways. The master shipwright would lay blocks of wood upon the ways, and then craft the entire ship, from the keel up, upon those blocks. Its launching illustrates how puny man, with primitive material, harnesses gravity to move mighty masses down a slope. So we know that the impossible can be done with small effort precisely placed.

All of the above, and all of the rest is sequential in nature. The earlier structures of Stonehenge were of wood, which the ancients learned was unsatisfactory for their measuring of the firmament. Wood, exposed to the elements, changes dimensions over time. Exactly how those previous structures and how the final structure was raised in place is of only peripheral import. There is no need to explore the differences of building up the earth by earth or by a wooden crib. Both have their merits, and neither merit is lost by combining the two. To clamber over a log crib in damp weather is treacherous, unless their open spaces are in-filled with earth. In the British Isles one may mind the gap, but not mind the rising damp, which is not infrequent. In the end a structure must be made in order to harness gravity.

Regardless, the erection of each stone is a piecemeal project. Interestingly enough, the first upper sill set in place could begin its use as a datum line for the horizon, just like any ordinary planetarium of today. Because the entire operation is piecemeal, various teams could move the stones from their original location. Repetition of the action makes each subsequent move that much faster. Equally, various teams could execute the rough cutting. As for the placement of the stones, one assumes that only one stone is raised at a time, or, fanning out from the initial placement, two at a time. A real master could start a second round at the further side. That would take a true master of measurement. Of course the completed structure is such a marvel of measurement, even that thought cannot be dismissed.

We built a flying staircase, more than one actually. That is a stair that circles upward from one floor to the next. It is tied only at the base, and at the top of the flight. Just to make it more difficult, and graceful, we made it narrow at the top, and constructed it to fan out as it approached the bottom. This involves offset radii for the inner and outer circles. The master framer, Ben, built the first tread on the ground floor in such a position that the next fourteen treads, each with an equal riser height, but with a different tread width, length, and angle, wound up in the air, step by step, to land at the top. It fit perfectly. As it went up we placed scaffolding under each new tread. Once it was up, we removed the scaffolding, plastered underneath, and we had a flying stair.

Perfect measurement, or near perfect measurement is rare, but not impossible on a job site. If Ben had been employed at Stonehenge, and the client wished the far side of the circle started simultaneously with the near side, he would have done it as a matter of course. He would have been elated when the final top sill plate was fitted into place. Elated, yes, but he would have been surprised only if it had not fit. For the expert to measure once, it is what it is. The sharp eye. The steady hand. No special rule.

One cannot close an analysis of the structure of Stonehenge without looking at the completed project. Once again, an image in Julian Richards' Stonehenge is suitable (#104). The stability and permanence of the construction was made hundredfold stronger upon the installation of the entire upper plate. As the holes in the ground prevent the bottom of the stones from shifting, so to the mortise and tenon and tongue and groove fastening of a structure in the round prevent the upper ends of the stones from swaying. How pleased they must have been with their perfect machine for viewing the continuously changing heavens. It would be interesting to see a mock-up, of wood, of the original, incorporating the existing erect stones and the same holes. Although I would not be counted among the star gazers, I imagine that the modern set would delight in moving back and forth from planetarium showing the past, and Stonehenge showing the present firmament at dusk, at dawn, and at night.


To meditate on Stonehenge and Avebury, one must first clear away the rubbish and look at what is there. To learn what is going on at both, one must be there at night. Night erases the present veneer. What remains is their essence, past, present and future. To learn what was going on at Stonehenge one must further be alone, in a room with a bright fire as a companion. That is where shadows play their shadowy games. One does not attempt the supreme difficulty of Stonehenge merely to see if the sun comes up in the morning and goes down at night. One does not require stone to see that. If one has a view, one can mark on the windowsill the sun rising in the east and setting in the west, all during the year.

With Avebury, the importance is that the stones are there. They are not metaphors. They exist. The trench, too, exists. It is not a metaphor, and it has no function but to exist. The outside bank exists by chance as a venue. A place to see, where one can assess the balance and harmony of the inner field, where one is separated from the inner field in order to absorb its eternal, unchanging existence. Stable, even with each new stone emplaced. It is all in how one looks at it. Go, thou stranger, to the East, to Crete, to Knossos. Climb the distant hill to the east, and look down upon Knossos. Return to Avebury, to climb Green Street to its terminus at the Ridgeway. Look down upon Avebury, and see what it is.

Compare this to Stonehenge, which is not studied from outside in order to observe balance and harmony inside. At Stonehenge the inside is used to study the outside. One studies the earth at one site, and studies the firmament at the other. One absorbs balance and harmony at one site, and studies the ever changing, constantly moving heavens from the other. One looks down. The other looks up. One looks at the round, uneven earth. The other looks at the round, perfect horizon, and above it, the perfect bowl. How the world does turn, and how different it is.

  List of Essays:

Time, Tools, and Measurements on the Occasion of Nova's Program on Stonehenge A Builder's Amplification

Stonehenge, Avebury, Silbury Hill: A Meditation on Function


© 2013
Website development by Morningstar Design