What does "Buddha Nature?"mean??
 

I came across this description of 'Buddha Nature.' "Buddha-nature or Buddha Principle (Buddha-dhātu), is shown, within Mahayana Buddhism, to be an innate, immortal potential for achieving enlightenment that exists within your brain of each and every sentient being. Buddha-nature isn't to be confused with the idea of Atman, or Self, but rather is seen to be clear of identifying faculties (also see Sunyata and Nondualism )." http://en.wikipedia.org/wiki/Buddha-nature I also found it defined in the reference of a book as -"Unrealised educated mind, the fundamental character of sentient beings." What does "immortal potential" mean - and just how can the potential (and fruition) for achieving enlightenment occur in your brain of an ant or perhaps a fish? Did the Buddha show about "Buddha Nature?" Comments??