MANY colleges say their mission is to mold young minds, but a few take it to the next level. They have a particular philosophy about how life should be lived or knowledge absorbed, and they want to make sure their students are not just reading about it or dabbling in it. They want their students to live it, day in and day out, for four years. Sound intense? It is. A bit offbeat? That too. Such colleges are not for everyone, nor do they want to be.