I take this to mean that a theory is a sort of cross-section through the motorcycle engine of reality. There may be many theories that deal with the same reality. That doesn't mean that one is right and the others are wrong. But each leaves out different aspects of the reality they deal with. There are maps and maps.
Different maps choose to represent different features of the territory.
Several maps, taken together, may provide a better understanding of the territory than any one map can. Bob Dick 1999. This document may be copied if it is not included in documents sold at a profit, and this and the following notice are included.