I want to know the answer to the following question:
Which city in the mid-18th century became the center of an explosion of philosophic and scientific activity?
All the background I'm provided with is that "While the Philosophes of the French Enlightenment were not revolutionaries, and many were members of the nobility, their ideas played an important part in undermining the legitimacy of the Old Regime and shaping the French Revolution.". Is that enough to answer the question?