All this talk of conceptual categories left me wondering if I could catalogue them. Here's what I came up with:
1) Objective: Verifiable, testable statements about the physical world. e.g. Objects accelerate at x rate due to gravity. Virus A causes disease B through mechanism C.
2) Subjective: Experiential statements. I feel cold. I chose to go to the store. I love you.
3) Descriptive: Statements of value about something. She's pretty. Good job. This town is boring.
4) A priori: Definitions. A dog is a living organism with X characteristics; Blue is light of these wavelengths.
There may be more, but this is all I could come up with on the way back from Taco Bell.
The first thing I noticed was that the first three types all come down to a priori concepts in the end. That is to say, "This worm is 2 cm long" is an objective statement -- but it depends on an a priori definition of what a worm is, what a centimeter is, and what the word "2" means.
The second thing I noticed was that you can retranslate just about every sentence among the first three. For instance, "Ouch! I'm in pain" (subjective) Ouch! That hurts! (descriptive) and "The contact between your elbow and my chest caused X reaction in my nervous system." (objective). Each of them looks at the event from a fundamentally different vantage point. The first expresses feeling. The second expresses judgment. The third describes reality.
And then I wondered, "if we can state things from all three angles, I wonder if we can examine them from all three angles." Obviously, you study objective reality through the scientific method. Subjective reality must be studied through introspection -- looking into your own experience. Descriptive reality must be studied with respect to a purpose. That is to say, "This is the perfect car" presumes a set of criteria in the mind of the speaker for what a car is intended for -- criteria that exist independently of the characteristics of the car, but which the characteristics of the car happen to match.
The next thing I noticed was that you can't study one category with another category's means. For instance, you can't study the characteristics of a frog through introspection or determining what the frog is useful for. You can't study why you're afraid of the dark with a microscope, or say it's not useful . And you can't determine whether a woman is beautiful or not with a ruler, or hour of meditation. Each type of statement has to be evaluated in its own way.
And then I thought, seems like most philosophical disputes come down to a failure to place concepts in their proper category. Scientists, for instance, seem to want everything to be studied in an objective manner. That works for some things, like chemicals in a test-tube. But it doesn't work for philosophy, interpersonal relationships, or self-awareness. Little wonder so many masters of the lab are failures in their own mind and life. Similarly, subjectivists seem to want everything to be an extension of their feelings. If they feel a thing, it is true. They argue that science is just a rationalization for the emotional biases of the scientist. And surely it often is -- but not when science is properly applied through its proper tools, and in its proper scope. Finally, the religious tend to see everything in terms of its inherent "value." Man is "evil." God is "good." sex is "only for marriage." The purpose of life is to serve God. Always judgment, evaluation, and purpose. And surely sometimes that is good. But they often neglect simply understanding what is (objective world) or what they are actually feeling (subjective world), constantly evaluating, and never understanding.
Is it any wonder that groups looking at the world through such radically different epistemological glasses would come into conflict? They literally look at the same event, person, or phenomenon, and see something completely different. No wonder the bickering never ends.
I think I might be onto something here.