We all 'picture' the world in our own way and use this picture as though it were a direct vision of reality. This works perfectly well for our everyday activities. But since the beginning of intellectual thought, philosophers have recognized that what we hold in mind is just a feeble representation of a 'reality' which it may not be possible to reach. The 'picture' we hold in mind is in some ways like a map of the area, which shows certain key features that affect us. But even for practical use we need more than one map. When I want to find my way around London on foot I use a Google map. If I want go by rail I use the underground map which looks very different. Both are accurate and both show different aspects of the same subject.

This essay is an attempt to show our world simply and clearly as one coherent whole. It is just one of many possible pictures that would be needed to show everything.