I think there is value in subjective, qualitative software analysis. I think that is a guiding principal of Exporatory Software Testing (ET): "Should I look here or over there?" and our well trained instincts guide us. So what trains us and what are those instincts? Ideas worth looking into.
I rely on the "One Roach Conjecture": "If you see one roach . . ."
I frequently use this principal while performing ET. For example, I look to see if there is a simple parsing problem, if there is, then I think, "Ah HA! These programmers don't know how to parse. I wonder where else parsing is critical to the function?" (Examples of simple parsing test cases: 0.0.0, --1, -0. I found that Acrobat Reader had a lot of trouble with these. ergo . . .)
The subjective led to the objective so I think exploring subjective analysis has some bearing on our software testing craft.
(A slightly different version of this post appeared Oct 27, 2010 in the "Software-Testing" Yahoo group.)