Infact, if you add 2 apples to 2 apples you get 4 apples. But if you add 2 apples to 3 oranges... what do you get? Yes, you get 5 fruits, but you will loose the particular aspect of the apple and of the orange that you started with. So let's focus on the fact that usually we deal with 4 fundamental dimensions or units in:
... and that we CAN NOT obviously add a Time measurement (say 5 seconds) to a Length measurement (say 1 mile) because it makes ABSOLUTELY NO sense.
(1 sec + 1 mile = ???)
From these 4 dimensions we can talk about the 80% of ALL physics problems existing now or in the future... (Future?? Who knows the future??)
If you want to talk of the other 20% you need to add other 3 dimensions
Once we agreed on so... How would you measure ESP ([Extra Sensorial Perceptions]?)? (LOL) :) (So we can talk about 101 % of physics now, say metaphysics)
see SI
/comments?