Indeterminacy and approximation in Mediterranean weight systems in the third and second millennia BC
Research on weight systems used during the Bronze Age, prior to the introduction of writing,
generally assumes that the widespread use of metal as ‘commodity currency’ eventually resulted
in the adoption of widely shared systems of measurement. Many studies aimed at the identification
of recurrent weight values as multiples and/or submultiples of theoretical standard units. This
approach faces two limitations: 1) the absence of written sources, or at least statistically sound
samples, makes it difficult to either validate or reject any reconstruction of prehistoric systems;
2) in the literate Ancient World, different polities usually retained distinct systems. Here an
alternative analytical framework is outlined, making use of elementary statistics and crosshistorical
comparisons, and relying positively on ‘indeterminacy’ and ‘approximation’ rather
than on ‘exactness’. Recurrent weight measures can correspond to ‘Standard Average Quantities’,
rather than representing arrays of exact multiples/submultiples of given units. By departing
from a ‘fractional’ theoretical logic, one can observe that constant exchange practice may have
produced the normalisation of ‘tradable quantities’ and that this can happen without necessarily
implying the unification of local systems.