> >>All ancestors have a (one) common human descendent.
>
> If ALL decendents have a common ancester, then all ancesters have
> something in common with any one descendent).
BING! (sound of lightbulb going on)
I see--if all descendents have a common ancestor, then all ancestors have
common descendants, because the only isosemantic "ancestor" will be the
one from which a descendants are... well,... descended.
Right?
-Prof. Tim