first off the emergence of the age of enlightenment was in the late 17 century scientists such as isaac newton and john locke challenged the old order.
it happened because of a movement, here are some reasons 1) the clout of the Church and State and the power struggle between them 2) the Western discovery of new societies with radically different cultural traditions and norms. 3)Many intellectuals also felt discontented with the fixed social striations among their own collectives, 4) people were angry at their governments' unwillingness to grant personal rights.
these are just a couple out of many reasons why it sparked up
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