Do you know how psychics learned about the paranormal etc.BEFORE computers etc.?

I remember seeing little houses etc. where psychics read your fortune with a crystal ball etc. They didn't seem to have much money ...and I'm sure no Degrees. Where do you think they (and others who knew about horoscopes, numerology, etc.etc.) get their "learning" from? These things are complicated and not usually in library books. I guess information was ped down through generations...but I'd think you'd need a cl in this to really know about all these things...at least a computer. (I don't think there was much in encyclopedias either) Maybe someone on here has relatives who knew about these things. How did they learn? Who taught them? Thanks.