Catholicism is a community, a tradition, a vehicle of revelation, and a world. The word means “universal” or “all-inclusive.” The Catholic Church is therefore the Church that is not partial but possesses by right the whole of Christianity and truth. The extent to which particular Catholics, including Church officials, exercise that right of course varies.
God is at the center of all things and explains all else. If you don’t know Him you won’t know anything else properly. Nonetheless, the Church recognizes the relative autonomy of things: nature speaks to all men, and Christ is not the same as Caesar. Catholicism allows for a diversity of philosophical and theological understandings, but the diversity is not unlimited since some conceptions of man, knowledge and reality exclude the truth of Catholic doctrine.
There are a great many Catholic resources on the web.