Earlier quoted context omitted.
Having written a bit of Scheme and Clojure - Clojure's distinction between data structures make many things simpler - from writing code to writing macros. As far as his comments on testing - I suggest you read this, http://blog.8thlight.com/uncle-bob/2011/10/20/Simple-Hickey....
Importantly, it should be mentioned that despite the way it distinguishes between different data structures, Clojure manages to retain the advantage of "representing everything with parens" by instead making sure that everything implements a common _interface_, (i.e., seq). In other words, as opposed to CL or Scheme, it separates logical list manipulation from the physical data structure, giving the best of both worl…
The point I was trying to make about parens is that I think Rich is creating a straw man from them. Parens in CL/Scheme don't have any special meaning other than demarcating lists. A Lisp compiler/interpreter just evaluates lists of symbols at the end of the day.