First, they often teach their disciples in metaphors and with parables, to emphasize a point. These metaphors and parables are how the teachings are passed from one generation to the next; whether verbally or in writing. The metaphors can be effective, but they can also be the root of misunderstanding. When the founder is alive, the disciples can ask for an explanation of the metaphor (how much is literal, how much is illustrative, how much is meant to be law, how much is just for art). A parable can just as easily be misinterpreted – it might not have the same meaning in Latin as it does in Greek because some words simply don’t translate. Parables can also have a different meaning in the context of a different culture. Telling a parable about an olive tree will have a different meaning when told to a Greek than when told to a Samoan. Because of this, even when the founder is alive their teachings can be misinterpreted. With different interpretations, diversity flourishes.
Secondly, people tend to hear, see, and remember in different ways. Even when we are at the same place, at the same time, our brains are selective about what information is allowed to enter. I may remember the birds in the background noise, but you remember cold wind. After the founder is gone, and sacred texts are written, memories and experiences are compiled. What was important to me (the birds) may hold no weight for you, and vice versa. Again, diversity arises.
Thirdly, founders of religions tailor their teachings to the societal and political events of their time. Otherwise, what they teach would not be relevant to their followers. While some ideas are universal, others are not. This creates diversity as the teachings spread to other lands, and as they survive time. (For example, Jews who worked on the Sabbath could be put to death [Exodus 35:2 – Moses is considered one of the founders of Judaism]. This is not a socially acceptable practice in today’s society.) Disciples must then resort to deciphering the meanings with whatever societal knowledge/conditions they have. Our societal and political conditionings are different today, even from just fifty years ago much less five thousand years ago.
Even when the religion’s founders are alive, it is possible to have very little unity amongst followers.
Additional reading:
Jesus' followers not at his crucifixion
Buddhist doctrine and conflicts for anthropologists
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