When the right basis has been laid, cultural development in a society could become spectacular enough to usher in a Golden Age. With this Policy, great inspiration comes to all your citizens, whether they dabble with culture or not. This effect is particularly strong in cities which have constructed amazing buildings, which can serve as inspiration for the artists to really outdo themselves.
- Culture increased by 33% in all cities which have built a World Wonder.
- The empire immediately enters a Golden Age.
This powerful mid-level Policy has both a long-term and an immediate effect, and both have the result of increasing your total Culture output, so you should aim at adopting it as soon as possible. Since it depends on both level 1 Policies, it stands to reason that this should be the third Policy in the tree you adopt, unless you really need a Great Artist at this very moment (in which case you should go for the other level 2 Policy).
This Policy is the more effective the more cities you have with Wonders in them. Note that the number of Wonders in each city doesn't matter - even one will trigger the Culture increase. On the other hand, a single city with many Wonders in it won't have a greater Culture increase - the bonus is still capped at 33%. Also note that only World Wonders (such as the Great Library) apply, and not National Wonders (such as the National Epic).
"Flourishing of the Arts" generally refers to a period of heightened aesthetics characterized by great production of innovative art, usually in conjunction with a civilization's Golden Age. Along with advances in science and living conditions, the "flourishing of the arts" during a golden age affects all forms, literature and music as well as the material arts. Unfortunately, every such cycle inevitably is broken, usually due to outside influences such as war, economic collapse, religious fanaticism, or other circumstances beyond people's control.