You translate the properties into logical definitions like
for all knowledge K, if entity E is omniscient, then E has K.
Then you show that possessing two of the properties simultaneously
leads to a contradiction. Check out "Atheism" by Michael Martin,
especially ch. 12 "Divine Attributes and Incoherence".
-- David McFadzean david@lucifer.com Memetic Engineer http://www.lucifer.com/~david/ Church of Virus http://www.lucifer.com/virus/