Dody's thread over in I&A got me to thinking about this. For governments that have established empires, why don't we say they're empirical?

Because they have different roots. Empire is from the Latin imperare, to rule; empirical is through Latin from the Greek empeirikos, experienced.

Thank you, Mr. F. I had a feeling it would be something like that. Although I am too familiar with the "real" meaning of empirical to be able to seriously ascribe it as I said above, it still makes grammatical "sense" to me; I guess in the same way that toddlers say, "I tooked a piece of candy".

You could say, I suppose and at the risk of being laughed at, that the government was empireical.