Final answer:
The core value of the Enlightenment thinkers that said truth, even in social systems, could be discovered through thinking and applying the scientific method is Reason.
Step-by-step explanation:
The core value of the Enlightenment thinkers that said truth, even in social systems, could be discovered through thinking and applying the scientific method is Reason. Enlightenment thinkers such as John Locke, Voltaire, and Immanuel Kant emphasized the power of reason and rationality to understand and improve society. They believed that through the use of reason and scientific inquiry, society could progress and achieve liberty and happiness.
Learn more about Enlightenment thinkers and their core value of Reason