Why sacrifice works...

"Meaning inheres in why provisions, feasts, and gifts are considered appropriate, in what they are thought to accomplish, in what relationships they establish. Similarly with sacrifice, itself both function and meaning. Sacrifice cements alliances, creates passageways between this world and the next, and is a political tool, but its meaning ultimately lies elsewhere. It is why sacrifice is understood to be the proper way to do these things that is the ultimate object of inquiry."—Ann M. Porter in Sacred Killing , page 193 

<idle musing>
And we don't really know why, do we? "It just works" seems to be the default answer. Is there something inherent in humanity that thinks we need to offer something up? The Christian would answer yes and point to the cross.
</idle musing>