"The reasonable doubt formula seems mystifying today because we have lost sight of its original purpose. At its origins the rule was not intended to perform the function we ask it to perform today: It was not primarily intended to protect the accused. Instead, strange as it may sound, the reasonable doubt formula was originally concerned with protecting the souls of the jurors against damnation."
I find this a fascinating bit of social history. Truly, there is nothing about a society that is not the product of its history and culture, and that is even more true when we're unconscious of those origins. That taken-for-granted background cultural knowledge shapes our values and creates a shared sense of right or wrong, good or bad, and fair or unfair.