Final answer:
Conservative establishment feared Enlightenment ideas because they represented a radical shift from traditional monarchies to governments that recognized individual rights and shared power, challenging established social and political hierarchies.
Step-by-step explanation:
Conservative establishment members were frightened of Enlightenment ideas because they proposed new ideas that radically changed the way people thought about the foundations of political states. Central to this fear was the shift away from the long-standing divine right of monarchies towards concepts like constitutional monarchies or republics that emphasized shared power and individual rights. Enlightenment thinkers such as Locke, Voltaire, and Rousseau brought forth the ideas of government accountability, the protection of natural rights, and the possibility of replacing a government that fails its people. This fundamentally challenged the established order and was seen as a threat to the entrenched power structures and social hierarchies of the time.