Differences are the things that get into the map

Let us go back to the map and territory and ask: “what is it in the territory that gets into the map?” We know the territory does not get into the map. That is central point about which we here are all agreed. Now, if the territory were all uniform, nothing would get into the map except the boundaries, which are the points at which it ceases to be uniform against some larger matrix. What gets into the map, in fact, is difference, be it a difference in altitude, a difference in vegetation, a difference in population structure, difference in surface, or what-ever. Differences are the things that get into the map.

Gregory Bateson, Steps to an ecology of the mind, p320
http://www.seekeraftertruth.com/ebook-gregory-bateson-steps-to-an-ecology-of-mind-1972/