Just a quick thought on the JyllandsPosten cartoons: if religion is related to morality, then sacred symbols have to be local at least to a particular community. The sacred, in this sense, which I found in David Sloan Wilson, is distinct from the numinous, which I find in the world around me, as does everyone. But most people find it in different places from me, and where I find it varies over time. The sacred symbol, by contrast, is fixed and always sacred and hedged about with taboos.

DSW would say that this is because the sacred must be lifted above all ordinary social and negotiable relationships if it is to function. It is a kind of imperative. It ends argument, as the Supreme Court is supposed to do. But this is itself a social funciton of course. The sacred functions within particular communities. Thus, the urge to spit in Mohammed's eye is a declaration that we don't want to be bound by the laws of Islam, an essentially political statement. (Nice irony that it turns out that even secular societies cannot disentangle politics from religion in some contexts)

If the sacred is a mechanis by which a community understads its own morality, then the horror of blasphemy becomes a little clearer. Since altuistice behavrious is always vulnerable to defectors and cheats, they have to be stamped out. Altruism, in this context, always applies within a group. Hence the intuition that morality must be absolute if it is to be valid. Blasphemy is a declaration that the blasphemer is -- in game theory -- a defector, a cheat, someone who won't play by the rules that constitute society. The only way out of this bind is to find some larger, common loyalty, something which is left as an exercise for the reader.