This is one of my favorite topics, more so than the usual topics of rationalism perhaps, and I've thought about it a lot. How can we best believe things we accept? The other day I was out running and the moon was large and visible in the daylight. I was looking up at it and thinking to myself, "If people really understood what the moon was, what the stars are, what Earth is, could they go on living the way they do? If I really, genuinely knew these were other places, could I go on living the way I do?" This is, perhaps, too romantic a view of things. But it illustrates my point: we really do accept very profound things without ever truly making them part of our person. It's not just the absence of ghosts and other supernatural entities we have difficulty with but the presence of many phenomena outside our usual experience.

Paul Churchland's early work, Scientific Realism and the Plasticity of Mind, has a great illustration of this. Churchland's mentor was the American philosopher Wilfrid Sellars who developed a distinction between the "scientific image" of the world and its common sense "manifest image." Churchland's approach is to give the scientific image preeminence. He wants science to replace common sense. This larger project was the background to his more familiar eliminative materialism (which seeks to replace folk psychology with a peculiar connectionist account of the brain). While most of the work is quite technical there are some excellent passages on how we could achieve this replacement. He discusses the way we still talk of the sun rising and setting, for example, and uses a particular diagram to show how one can reorient oneself to really appreciate the fact that we're a planet orbiting a star.

I've tried to post the diagram here:

http://s5.tinypic.com/zinh38.jpg (before we reorient ourselves)

http://s5.tinypic.com/2akfoll.jpg (after we reorient ourselves)

I don't have the descriptive text at hand but for me what the diagrams illustrate is a particular approach to science that I think Eliezer shares, more or less, which is that we should try to incorporate science deeply into the way we inhabit the world. I suppose that, to me, is a major part of what rationality is or should be: How can we best live that which we have until now merely accepted as fact?