What makes Lisp...Lisp?

If you starting removing features from Lisp, at what point is it no longer Lisp? Some people claim Clojure shouldn't be considered a Lisp. Is it because too much Lisp was removed?

What is at the very heart of Lisp that makes it Lisp?

>>35
this works only with one type
No, it doesn't.
you can't use the macro twice
Yes, I can.
simply because you have to enter the type name anyway inside the body of the function (to access data).
No, I don't.

Go back to learning C before trying to discuss it.
Hint:
MAPCAR_INSTANCE(char);
MAPCAR_INSTANCE(int);
MAPCAR_INSTANCE(void *);

MAPCAR_INSTANCE_DEFINITION(char)
/*...*/