The dissemination of divination in roman republican times

information sought, F = the frequency that this context arises, S = Survival – probability that the
practice will survive, A = Adoption of a new practice.
Ad 1) This equation states that the credibility value of a divination practice is composed of
three factors which have a different weight each (a, b and c). We don’t know the exact value of
these factors, but we do know that ritualization is the most important. The second most important
is direct prestige, and the least important is indirect prestige. Thus the weights of the three
factors are a>b>c. Ritualization is a binary factor. Indirect prestige varies with the direct prestige
and may be slightly higher or slightly lower. IP probably depends on R>0, but it is a different
problem whether the IP remains a factor outside ritual divination. 183 The equation also predicts
that the credibility value of an utterance which is not ritualized, that is when R=0, can be
evaluated according to the normal human heuristic of prestige bias. This is because only DP
remains.
Ad 2) Equation 2 states that the probability that a practice will be disseminated is inversely
proportional to the credibility value of the practice. The reason for this can be learned from a
basic insight from economics. Divination is a service and as such economicly a commodity. Like
all commodities it has a value. This value correlates with what we have here called credibility
value. It should not be controversial that the more credible some information is (credibility
value) the more valuable it is (actual value). The probability of dissemination correlates with
demand. In economics this relation between value and demand of a commodity is expressed in,
what has been termed, the demand curve. The basic prediction of the demand curve in economics
is that ceteris paribus, high price of a commodity results in low demand and low price in high
demand (Mulhearn & Vane 1999: 28-30). Likewise in divination we should expect high
credibility value to result in low demand and low credibility value in high demand. It is however
necessary to remember that this is a ceteris paribus claim, so other factors may result in a low
credibility value practice not being widely disseminated, just like a cheap good does not
necessarily result in high sales. It could also be argued that utility should be part of this equation
183 One could here imagine revelations or prophecy as positive examples, because the ultimate communicator is a
god. For an interesting analysis of these implications see (Levy 2007)
186