As I went on my morning walk today I noticed the frost on the ground in the shape of a tree. It seemed to me the perfect illustration of the debate at the heart of Book 12 of the City of God – how does a changeless God relate to a changing world?

Augustine’s opponents were suggesting that God’s decision to create time & nature somehow reflects a change in his essential being. How can he go from being in perpetual eternity, outside of time, to then creating the world in a specific moment if God cannot change?

This is a lot more practical than it sounds. Essentially the arguments Augustine is dealing with here are very similar to the debate a few years ago on Open theism. This debate sought to highlight the bible verses that talk about God changing his mind, or changing a decision based on human activity.

Both the modern and ancient questions drive at the heart of God’s relation to his creation – either in its inception or its growth. Although I am finding I don’t agree with Augustine on everything in this book, his reasoning on the question of God’s unchangeable nature (his immutability) is outstanding.

His opponents were suggesting that perhaps God has always been sovereign over creation because there have been an endless cycle of birth, growth and death of planet earth and humankind. They argued that this cyclical theory avoids God transitioning from an eternity of nothingness into a time bound physical universe. Augustine argues that no matter how many cycles there have been there must have been a beginning to the process, and compared to this:

“any space of time which starts from a beginning and is brought to an end, however vast its extent, must be reckoned when compared with that which has no beginning, as minimal, or rather as nothing at all.”

XII.13

There was a moment when eternity observed the birth of time and the invisible beheld the arrival of the material world. Augustine recognises this is “certainly a profound mystery that God existed always and yet willed to create the first man, as a new act of creation, at some particular time, without any alternation in his purpose and design”.

Augustine is right to warn against digging to deeply into this mystery. I think the problem with trying to probe this mystery is that we are bound within time. It’s like the frost on the ground in the shape of a tree. A child might observe this and wonder how a tree’s shadow can make the ground so cold it creates frost within the shadow, while the ground all around is green. When time is taken into account we realise that it’s not that the tree’s shadow causes the frost, but that the sun is melting all the frost except for that protected by the shadow. The effect of time on the movement of the sun fools us.

So too we look at the “changes” that God instigates in time from our perspective and try to peer into eternity from within the tree’s shadow. It is impossible. Only the one who is outside of time can answer these mysteries.

“Every infinity is, in a way we cannot express, made finite to God, because it cannot be beyond the embrace of his knowledge”.

XII.19

All this is to do with origins, as Augustine is dealing with the origin of the Two Cities in this book. I suspect we will get to the even bigger brain-buster on this theme, which is the incarnation. Never mind God entering time from eternity, what about the omnipresent God entering a human body? Faith rests in the wisdom and revelation of God, unbelief asks why the tree’s shadow is producing frost.