In the sense in which conceptually pure was being used upthread for langauges which have a very strong opinion on the constructs appropriate for software development (Haskell with pure functional programming, Erlang with actor-model concurrency), I don't see Lisps in general, including Clojure, as being conceputally pure (there is a kind of conceptual purity there, but its at a lower level and in a sense opposed to the kind of purity at issue here, as I see it.)

Clojure is a lisp, but that's not why it's coherent. It's coherent because it has a clear model of data, state, abstraction and computation. It's not only clear, but (like Erlang) resembles the way people think about the world and about computation.