In my high school physics class we spent some time studying light.  Part of that was learning about things like angles of incidence and angles of reflection and how light acts with prisms and mirrors.  He told us a story about their bulldog.  On their front door they had a small mirror mounted low enough that their dog could see his reflection.  Whenever he did, he would run to the other side of the door, a distance equal to his original distance from the mirror, and bark ferociously at that other dog.  He was always frustrated though, and didn’t quite have the intellectual horsepower to figure out that it was just an image and he was barking at himself.

An image is a more or less exact replica of some original thing.  In a mirror it tends to be exact, unless you’re at the funhouse; in artistic expression, somewhat less so, but still discernible.  Scripture says that God made man is his own image and likeness.  What does that mean exactly, especially since God doesn’t have a body as we do?  In what does the image consist if it can’t be seen in a mirror?

We shall take the terms image and likeness as synonymous; the question of the exact nature of the image is more difficult and more controversial.  There are many things that have been alleged, but basically the question divides along two lines.  Is the image structural, referring to something we are, or is it functional, referring to something we do?  Functional definitions tend to be more modern, perhaps in line with the shift in philosophy away from essences.  Structural definitions dominated theology until the modern era.

The primary understanding of this term has been rational/moral.  Holiness is often listed as one of the preeminent attributes of God, having to do in part with his aversion to sin.  He knows good from evil and his character is good, providing an ultimate definition of that term for us.  We need such a definition because we also are moral beings.  We constantly make moral judgments and they are made of us.  Why do we do that?  Why do little kids learn to say, “But it’s not fair!” without us having to teach it to them?  The theological answer is because we are made moral in the image of a moral God.

Likewise with rationality.  One way to understand God is as an infinite mind, a mind that works using the laws of logic.  (A thing cannot both be and not be in the same sense at the same time even for God!)  We also have this capacity, warped as it is by sin, but still present.  We are capable of making rational decisions and rational judgments.  Truth and error are meaningful categories both to God and to us.

These aspects of our nature make us creatures capable of relating to God in a meaningful and personal way, unlike all the rest of creation.  They also provide the basis for human governance over creation, and things like artistic expression.  Because we are rational, God can speak to us and we to him.  Because we are moral, we can obey and do so in a way that is meaningful.  It also means that when we disobey, judgment can be legitimately imposed, both by God and by parents.

It is this doctrine of the imago Dei, the image of God, that makes man so special in biblical thinking and has driven the value of the person in Western thought, unfortunately now under severe attack.