Based on the discussion under the "Socrates" thread and some philosophical observations by Phaedrus, I thought up a way of thinking of the functions in terms of their associated fundamental skepticisms and beliefs.
This list could probably use some refinement; I would be interested in people's comment.
Skeptical of objective reality. Skeptical of absolutes, and of moral or aesthetic principles. Believes in the value of systems.
Skeptical of systems. Believes in "ideal states." Skeptical of the ability to understand the physical world directly; the world of ideas is more real.
Skeptical of anything that can't be clearly demonstrated. Interested in debunking mystics and other "magical" thinkers. Believes in what can be demonstrated rationally.
Skeptical of the value of things other than physical pleasure or activities one enjoys (whether work or play). Believes in one's individual power to experience things in a way that will make everything all right.
Skeptical of what one can't see or experience personally; skeptical of theories. Believes in one's own experience.
Skeptical of others' intentions. Believes in moral principles.
Skeptical in the value of things that don't relate to people. Believes that certain priorities and actions can make life meaningful and worthwhile.