As I said in Part 1, which you should read before this part, Some would claim the answer to these questions is that there is a God. One who chose to create the universe the way it is. It is reasonable to ask who or what created the universe, but if the answer is that “God chose toâ€, then the question has merely been deflected to that of who created God. In this view, it is accepted that some entity exists which needs no creator, and that entity is called God. It has been claimed, however, that it is possible to answer these questions purely within the realm of science, and without invoking any divine beings. According to the idea of model-dependent realism our brains interpret the input from our sensory organs by making a model of the outside world. We form mental concepts of our home, trees, other people, the electricity that flows from wall sockets, atoms, molecules, and other universes. These mental concepts are the only reality we can know. To put it more simply: We see the universe the way it is because we exist only in this universe.

There is no model independent test of reality. It follows that a well-constructed model creates a reality of its own. An example that can help us think about issues of reality and creation is the Game of Life, invented in 1970 by a young mathematician at Cambridge named John Conway.

The word “game†in the Game of Life is a misleading term. There are no winners and losers; in fact, there are no players. The Game of Life is not really a game but a set of laws that govern a two dimensional universe. It is a deterministic universe: Once you set up a starting configuration, or initial condition, the laws determine what happens in the future.

What makes this universe interesting is that although the fundamental “physics†of this universe is simple, the “chemistry†can be complicated. That is, composite objects exist on different scales. At the smallest scale, the fundamental physics tells us that there are just live and dead squares. On a larger scale, there are gliders, blinkers, and still-life blocks. At a still larger scale there are even more complex objects, such as glider guns: stationary patterns that periodically give birth to new gliders that leave the nest and stream down the diagonal.

If you observed the Game of Life universe for a while on any particular scale, you could deduce laws governing the objects on that scale. For example, on the scale of objects just a few squares across you might have laws such as “Blocks never move,†“Gliders move diagonally,†and various laws for what happens when objects collide. You could create an entire physics on any level of composite objects. The laws would entail entities and concepts that have no place among the original laws. For example, there are no concepts such as “collide†or “move†in the original laws. Those describe merely the life and death of individual stationary squares. As in our universe, in the Game of Life your reality depends on the model you employ. The example of Conway’s Game of Life shows that even a very simple set of laws can produce complex features similar to those of intelligent life.