All the Pope is doing is bringing out Catholic doctrine that has been neglected for the last 40 years. Faith is a gift: but human reason is capable of perceiving God through his work. Obviously, this is completed through the preaching of the Gospel, the acceptance of revealed truth, and, ultimately, faith. But in Catholic theology, God has left his mark on his creation for all to see; furthermore, he has created Man in his Image and Likeness, so we really have all the information we need. Faith - that is, the personal relationship - is a gift and something that can either be accepted or rejected.
On the practical level, this is the basis for Catholic natural law theory, which of course is enshrined in our Constitution (the Enlightenment simply took many classical pre-Reformation Christian concepts and secularized them).
Absolutely.