Rationalism, Empiricism, Subjectivism

John M. Frame suggested a new framework for knowing what knowledge is in 1982. (This philosophical sub-discipline is called "epistemology.") He begins by listing three general types of epistemology throughout the history of philosophy:

The first tendency is rationalism or a_ priorism, which I shall define as the view that human knowledge presupposes certain principles known independently of sense-experience, principles by which, indeed, our knowledge of sense-experience is governed. The second tendency is empiricism, the view that human knowledge is based upon the data of sense-experience. Thirdly, there is subjectivism, the view that there is no "objective" truth, but only truth "for" the knowing subject, verified by criteria internal to the subject.

I tend towards empiricism, myself, with a healthy respect for rationalism, but I have long despised "subjectivism." Frame's description of subjectivism convicts me of intellectual snobbery:

Then comes the third member of the triad, human nature, which correlates with philosophical "subjectivity." Self-knowledge has always been philosophically difficult. As Hume and Wittgenstein especially have pointed out, the self is not one of the things we see as we look on the world. Yet it is through our­selves that we come to know everything else. All we know, we know through our own senses, reason, feelings, through what we are. And it is thus in knowing other things that we come to know the self. The self seems to be everywhere and nowhere. We know it, but only as we know other things.

Frame does not take two opposing principles and merge them into one synthesis, as Hegel would do with his dialectic. He affirms three different perspectives as co-equal--like the three dimensions of physical space.

My approach to knowledge, up until now, seems two-dimensional at best? Has my epistemology been just a cardboard cut-out with no subjective depth to it?