Sonnikke,
For as long as mankind has had "great thinkers" this arguement/question has rolled around. Each time a new compelling distinction between man and the rest of the animal kingdom is ushered out, it is met with great enthusiasm, and then is found to not be true.
Eg. -Once it was thought that language was the defining characteristic of the human being. But that excluded many of the deaf, whose inability to hear retarded language development. Then along came sign languages (which had actually been in use forever, as far as we can tell); but they were rejected as not true languages, rather simple gesture representaions of other spoken language. That was finally demonstrated as false, as signing has its own sentax, is able to express abstract thought, etc. The language distinction had failed, and the deaf were accepted as fully human. Makes sense.
Eg. -It was once thought that tool use was a defining characteristic of mankind, then we learned that sea otters (among others)use tools and the criteria changed. Now it became the
making of the tool which defined humanity; that failed too, since chimps make tools. So, on we go with the making of
complicated tools.
At last we have set upon the almost unmeasurable characteristic of consciousness.
Man knows who he is. It is this spirit which distinquishes man from animal. Of course there is no proof for this arguement, and dolphins/whales, elephants and chimps/gorillas have shown facinating suggestions of self-recognition and communication, family connection, etc.
The nature of every being in the animal kingdom is indeed unique, as each possesses a set of characteristics which distinguish it from the next. None of these differances, however, erase the overwhelming similarities.
BYW, in keeping with your criteria, my 3 y.o. duaghter is morphing from animal to human before my very eyes. Although she's not totally there yet, she does seem to satisfy three of your listed human distinctions:
1.Soul(which I believe),
2.creativity,
3.and by God the girl can talk!
-Shiloh
™ Version 4.2