The absurdity of cladistics

http://en.wikipedia.org/wiki/Evolutionary_grade
"An evolutionary grade is a group of species united by morphological or physiological traits, that has given rise to another group that differs markedly from the ancestral condition, and is thus not considered part of the ancestral group. The ancestral group will not be phylogenetically complete (i.e. will not form a clade), so will represent a paraphyletic [ancestral] taxon".

This is the absurdity of cladistics. 
When "a group of species has given rise to another group that differs markedly from the ancestral condition, it  is not considered part of the ancestral group."

So an ANCESTOR is not an ANCESTOR!!!

I expect that not many cladists even know about the absurdity buried within cladistics.