I love Richard Feynman's approach to questions about what we know and do not know...
I have approximate answers and possible beliefs in different degrees of certainty about different things, but I'm not absolutely sure of anything, and of many things I don't know anything about, but I don't have to know an answer.
I don't feel frightened by not knowing things, by being lost in the mysterious universe without having any purpose which is the way it really is as far as I can tell possibly. It doesn't frighten me.
I would rather have questions that can't be answered than answers which can't be questioned.