what "schools" of bass playing are there?

[Thomas Erickson]

This is a huge and twisted subject. IMO, good more for a lifetime of study and ten or so books, rather than a thesis. In fact, putting (essentially) the whole history of our instrument and the art of playing it into the context of a college paper might just be a little insulting. You are aware that many, many people spend their entire lives studying the one instrument, one method, and even a limited scope of music and never come close to perfecting any of it, right?