All my "learner's dictionaries" - Oxford, Cambridge, and Longman- say that "intelligence" is an uncountable noun which means " the ability to learn, understand, and think in a logical way about something" (and I should say that I have no access to OED).However, I came across "AN intelligence" while reading an article titled "Clever Hans" which was about an intelligent horse:
Hans the horse was bought in 1900 by Wilhelm von Osten, a retired German schoolmaster, who was convinced that animals had an intelligence equal to that of humans.
My question is, if "intelligence" can be used as a countable noun, does it differ in meaning from "intelligence" as an uncountable noun?