Isn't faith ultimately an epistemological question? In other words, what are the limits of human knowledge? How do we know what we know (or think we know)?

You assert that the only way to arrive at knowledge is through empirical observation or scientific method; through the five senses.  A Christian asserts that knowledge can also come through divine revelation; that we have a sixth sense. 

If this is true, then there is nothing irrational about faith. It's not a blind leap, if it is based upon a rational and coherent conviction that the New Testament represents genuine eyewitness testimony of the resurrection of Christ.