I tried to understand what you're getting at with that post but I can't be 100% sure.
Anyway, a clarification -- any part of the tongue is capable of discerning any of the five tastes. The idea that (for example) the tip of your tongue is the 'sweet' area is only partially correct: portions of your tongue are only more sensitive than others, not solely responsible for one um...gustatory sensation.
Here's an old article that shows how recent this discovery is (is the previous statement confusing or what?): sauce




