Map and territory
If you’ve confused two concepts, e.g. character sets and character encodings then, in map and territory terms, they occupy the same point on the map while occupying two different points in the territory.
Confusing the map with the territory is itself a common mistake. You then have a map in which the map and the territory are the same, while the territory is actually a separate map and territory.
In theory there is no difference between theory and practice. In practice there is.