I want to think about epistemology a little bit. That's not your usual religious topic, but with luck I can sketch a connection.

Epistemology, the study of what and how we know, has dominated philosophy and those fields that philosophy influences since the 16th or 17th century. Modern science and modern philosophy rose, hand in hand, with philosophy telling us that its central question is the epistemological one and with science giving us more and more reliable methods for knowing the world.

For both the goal was objective knowledge, and though for us that phrase usually means "knowledge that is more than merely personal," it meant something somewhat different earlier. It meant knowledge of objects, knowledge of the things we "look" at.

We can look at many objects visually, of course, but looking is a metaphor. It is a metaphor for directing our attention toward something: the subject is what does the directing, the object is what the subject is directed toward, and objective knowledge is the kind of knowledge achieved in the act of directing.

So strictly speaking subjective knowledge is knowledge that the person has of herself as a being directed toward the things in the world, and objective knowledge is the knowledge that she has of things as they appear in an act of intellectual looking.

The obvious problem is separating what I think I know about things in the world (but which are really the product of prejudices or mistakes of some kind) from the things I actually know about the objects toward which I direct attention. Science has methods of straining what we know so that the subjective elements slide through, leaving the objective elements for us to see.

In spite of that the philosophical problem of what we know remains. As Immanuel Kant helped us understand, the object of knowledge isn't the "thing itself." Obviously the appearance of my fountain pen isn't the same as my fountain pen, but the only things I direct my attention toward are my pen's appearances. We investigate phenomena—the way things appear to us—not the things "behind" those phenomena. Even if I know how a particular object always appears to human beings, I don't know for certain that the thing that is appearing is the same as the way it appears to us.

But that seems like a trivial difference, except to philosophers who have little better to do than worry about such questions. Most of the time the possible difference between the phenomena and the things themselves doesn't bother us. Most of the time my questions are about objects in ordinary situations. Most of the time the regularity of everyday life, on the one hand, and the methods of science, on the other, provide me with enough surety about what I know that I don't worry about the philosophical problem.

Besides, if I know how something always appears to us, what difference does it make if the thing itself isn't the same as its appearance? If we are talking about the objects of physical science, the answer to that question is "Probably little." But what if we are talking about things like God or the people I love?

In such cases we experience appearances, but we don't all agree as to what they are like, and we have no philosophical or scientific method for sifting out the merely personal from the objective. In fact, it isn't clear that there is anything objective to sift out, if we use the word objective in its stricter sense ("object of an act of intellectual directedness").