There are many one-time Evangelicals who convert to Rome in a quest for religious certainty. There are many problems with this move, but for now I’ll comment on just one:
The problem with the Catholic convert is that he simply stipulates an artificial standard of certainty, and then he constructs a belief-system around his stipulation.
This is a mistake. Unlike God, we are in no position to stipulate the way things must be or ought to be.
We are only responsible for what God holds us responsible for. Our level of certainty or uncertainty should be calibrated to the level of evidence that God has given us in any particular case.
If God wanted us to be more certain on this or that belief, he would have given us more evidence, or more compelling evidence, for this or that belief.
It isn’t the duty of a Christian to be more certain than God himself has warranted.
One doesn’t begin with some abstract standard of certainty, and then construct a belief-system around that artificial criterion. To do so is to play God.
Rather, we just go with whatever God has told us, whether more or less. We don’t have to be equally clear about everything, because God has not made everything equally clear to us.
We are answerable to God for what God requires of us. We are not answerable to God for what God does not require of us.
Indeed, when we aim for a target that God did not give us, we are not doing God’s will.
Of course, if you don’t believe in God or providence, then you can’t be certain of anything. That’s where transcendental theism comes in.