It is sometimes known as primordial wisdom
or self-born, naturally inherent wisdom. Brighter than the sun, according
to Buddha, it is always within our hearts. External knowledge must connect
with this inner wisdom or such knowledge is useless. Inner wisdom reveals
your buddha nature and that is enlightenment. There is nothing
else to be realized. When you discover inner wisdom, this world is nirvana.
Until you realize it, it is called samsara.