Jumping back into apologetics mode... I came across this site:
Below I will answer to what Mr. Gilbert has presented:
Is the Catholic Church a Christian church?
When we talk about God we often need to talk about him in parts. Because God is so big and our brains are so small, we need to be able to talk about him in manageable chunks. That is why we sometimes talk about the doctrine of the Trinity, or of Christ, of the church, of creation, and so on. However, because God is one and presents himself to us as a person, Jesus Christ, he is not reducible to those different parts; all these parts impact on and affect each other. You can’t change your doctrine about Jesus without it affecting your doctrine of the Trinity, for example. That is why when we learn and teach about God we study in a systematic way—so we can understand God best through an integrated and coherent system of truths, not isolated ideas.