What you're saying if I understand you correctly is that we don't know with any degree of certainty that:

1. There's a God
2. There's a Trinity
3.There's an afterlife
4. Humans have immortal souls.
5. We will be judged at the end of our earthly lives. 

These are all part of the dogmatic teachings of the Catholic Faith, and must be believed by Catholics under penalty of sin. Anyone who says that a teaching must be taught ex cathedra before it is binding upon their conscience, is woefully mistaken.