Man can learn nothing except by going from the known to the unknown.  ~Claude Bernard

    That statement sounds rather obvious but most of us behave as if it were not.  We try to learn not by studying or experiencing the unknown, but by digging into the details of what we already know and consider that learning.  Such learning is limited.  We have become so specialized in our jobs that we often carry that over specialization into our entire lives to the extent that we are not just missing the forest for the trees, we are missing the trees because we are concentrating on the leaves.  While specialization may be necessary in employment these days, we should take care to not limiting our growth, spiritual or otherwise, by too much specialization in what we do and what we study off the job.  
    In the area of spiritual and religious growth, I find it surprising how few people know anything about other religions, or even other churches, that the one they have always belonged to.  The usual reason given is "I believe in my church (or religion) so there is no reason for me to learn about other churches or religions."  My response to that is: If you truly believe in the church you belong to, why are you afraid to learn about others?  If your not afraid, than learning about other churches and other religions will help you learn to understand other people better.