Practical Epistemology Recycled

[Originally posted April 2010, but has been reworked a couple of times.  The original (with some comments) is at  http://therealtruthproject.blogspot.com/2010/04/practical-epistemology.html]

Wikipedia defines epistemology as "the branch of philosophy concerned with the nature and scope of knowledge". Traditionally it has led to questions like whether we can really know anything, and discussing the qualities of different kinds of knowledge like logical or mathematical knowledge.

How much attention has been paid, however, to the question "Who can I trust?" -- perhaps far and away the most important epistemological question that anyone can ask.