Fair enough, although I was asking a different question (not very clearly, I suppose). Is there a language X and a feature (or set of features) Y for which the following statement holds?
"Language X is more powerful than Lisp because it has feature(s) Y."
It's a bit more complicated than that. The key idea is that programs are composed of lists. But that idea is tied to several others:
http://www.paulgraham.com/diff.html