At the so-called "million-man" march on Egypt's Tahrir Square two months ago, estimates of the size of the crowd varied from 250,000, in Newsweek, to two million, on the Pakistani website CNewsWorld.com. Figures for recent protests in Syria have been similarly hard to pin down ("thousands" in the Daily Telegraph; "tens of thousands" in the Los Angeles Times). Estimates of European demonstrations seem to converge a little more reliably. According to the Trades Union Congress, "between 250,000 and 500,000 people" attended the London march on Saturday. The right-leaning Telegraph went with "at least" 250,000. At the same moment "some 200,000" turned out for anti-nuclear protests in Germany, according to the Associated Press. The protest organisers claimed 250,000.
The best way to count protesters was invented in the 1960s by the Harvard journalism professor Herbert Jacobs. It is hard to believe it had to wait until then. According to the Jacobs method, one simply divides the occupied space into equal sections, finds the average number of protesters across a few such sections, and then multiplies that figure by the total number of divisions. The approach has been enhanced by developments in aerial photography but its flaws are still obvious. How should one distinguish protesters from bystanders? How does one decide where the edges of the demonstration are? Despite these defects, the technique has no serious rivals.
At any rate, there is no more reliable procedure. In practice, the Jacobs Method is not used very often (America's Park Police is actually banned from using it). In most cases, the dominant approach remains "eyeball" assessment, also known as guessing, also known as making it up. It is of course traditional for supporters of a given cause to exaggerate their own numbers and the peacefulness of their movement. Opponents low-ball and focus on violent elements. Each side attempts to claim the weight of numbers and paint its opponents as anti-democratic thugs.
It was, I think, Elias Canetti who suggested that democracy might best be viewed as a kind of sublimated battle. At some point in the mists of time, according to this just-so story, it was discovered that by counting the members of opposing factions one could predict the outcome of combat. The weaker side could then save its skin and surrender in advance. In protests, this imagined violent core to the democratic process seems to rise to the surface.
Demonstrations occupy an uncertain zone between the civil and military realms. Protesters have contradictory goals - on the one hand, to keep the peace and avoid alienating their supporters; on the other, to terrorise, to punish the state and make it pay. Hence the inevitable squabbles about "rogue elements" within "otherwise peaceful" actions. Governments have the same dilemma, often attacking their own people and then apologising for it, or else "holding an inquiry" - by which ritual blame is parcelled out in harmless doses and the torpor of civil life is restored.
The logic of protest remains obscure. Some see it as a kind of super-vote, with participation calling for unusual passion and commitment. Protesters are therefore the tip of the iceberg: for every person on the streets there are five, or a dozen, or a hundred, privately willing them on (and perhaps this hypothetical portion could be held to approach democratic majority). Other theories paint protest as a species of military display, an intimidatory show of might, or at least of immovable resolve on the part of a neglected minority. The group may, moreover, gain strength and confidence in its public association.
There's something rather hazy about both these accounts, though. It isn't just that solid numbers could harm either adversary; the significance of any given total would remain uncertain. Better, perhaps, to stick with known unknowns. Politics is the art of the possible, as Bismarck said; that may be why all participants seem united against the science of the actual.