Sometimes people give as the aim for liberal arts education things like "to unsettle presumptions, to defamiliarize the familiar, to reveal what is going on beneath and behind appearances, to disorient young people and to help them to find ways to re-orient themselves." I think these sorts of things are truly ridiculous things to aim for in the context of any kind of college education, as I've argued , but suppose I were to take this as my goal in a philosophy course? What would I have to teach? What is the topic that has come up in my courses so far that has most consistently and most clearly had these effects? Neoplatonism. Nothing, nothing at all that I have ever taught, generates as much controversy and distress as Neoplatonism.If you just look very briefly and vaguely Neoplatonism, students just think it's weird. But start getting into details, when they start to realize that the weirdness is heavily argued, at great length, by arguments to which they often have no ready answer at all, and things change. I have had -- and I mean this quite literally -- students freak out, try to shout me down, or storm out. Fortunately those are not hugely common, but I have had all of them happen. There's no other topic that more consistently gets students arguing so intensely that it becomes difficult to keep them from all arguing at once. When people say that liberal arts, or philosophy, should challenge students' beliefs, they usually mean religious beliefs. I tell you true, if you really want to challenge the actual beliefs your students have, go over Plotinus's arguments for the One, or Boethius's argument in Book III of the Consolation of Philosophy that all human beings naturally seek the Good, which is God, which the One, and that true happiness consists in being God -- not being godlike, being God -- or even just go into detail into the Divided Line and how Neoplatonists argue for various things that Plato represents by means of it.And surprising as it might be, I think it's less of a surprise if you think about it: it really is radically different than anything most people are taught, but if you actually get into it, it is very tightly argued. It's alien to almost all the obvious features on which modern man congratulates himself for being reasonable about --. They can wave their empiricism, or whatever, at it, and it will look at them sardonically and proceed to eat their arguments. And why wouldn't it, really? Most of them have been building their philosophical views of the world by patchwork and piecemeal over a couple of decades; it doesn't really matter whether Neoplatonism is true or false, they're not going to have anything that can compete with any of the major examples of a philosophical approach that spanned centuries of intense and systematic philosophical discussion, ate most of its competitors, and spread itself through vast numbers of cultures from Spain to Persia. It's a mighty dragon, Neoplatonism, mighty enough to mock their assumptions as ridiculous. And never having come across the full thing, they don't have many weapons against it. Of course, that's all a melodramatic way of putting it; but really getting into Neoplatonism is generally like taking students through the looking-glass into a world they've never imagined.Yes, I am currently teaching Neoplatonism (Boethius and Plotinus on happiness) in one of my classes. Fortunately, no shout-downs or storm-outs with this class, but not a small amount of controversy, either -- very good and sometimes intense discussion.If you teach philosophy, what topic do you find most disorients students? Or, if you've had a philosophy class, what topics did you (or your class) find most disorienting?