Humans and Animals.

There's an article on the BBC today about the creation of six day human cell groups within cow eggs. The term for a human/animal hybrid, which has seen a lot of use lately in discussions about stem cell research, is chimera.

From the article:

"You may begin to undermine the whole distinction between humans animals and humans." -- Calum MacKellar

The only problem is that there are no distinctions between humans and animals on a scientific level. The only distinctions between a human and an animal life form is a blurry line drawn in the abstract, a border between two states in the wild country of lingual ambiguity and historical context. Can anyone give me a definition for the Homo Sapien which is does not revolve around our abilities? Can you do it without using concepts that we have in common with other animals? Is there more difference between man and ape than there is ape and bird? Try unravelling that ball of string, and you'll find nothing at its center.