Just listened to the branching out episode, another highly enjoyable one. As there is a talk of branches, I was wondering if function definitions with different arity branches are considered a conditional, or if they use a conditional under the covers (I assume they must do, I havent looked at the source code yet)

(defn hello
  ([] (hello "welcome to Clojure."))
  ([message] (str "Hello, " message))
  ([message & _] 
    (printlin "I can only cope with one message, sorry)
    (hello message)))