Hindu scriptures has been telling the same from time immemorial. Even most other religions like Christianity, Buddhism, Jainism tell the same thing. Hindu Seers have not only well-documented this philosophy through its numerous scriptures which give you deep knowledge about the Self (It is also called Spirit, Soul, Consciousness, Atma etc) but also provides lots of practical, well-established and time-tested tools and techniques like Yoga and meditation to realize your real nature i.e. that is your soul.
I don't see any need for a new “religion” for achieving self-realization (or enlightenment of Moksha or liberation or Nirvana etc). Moreover it seems that Scientology is a propaganda to achieve vested interests by some people. They are making it seem that it is their new “invention” for path to liberation and I seriously doubt whether it is any useful in the path towards enlightenment. Also the very name “Scientology” is a wrong word because it misleadingly suggests that it is a ‘new “scientific” way of life “unlike” other religions or spiritual traditions'.
in reference to: Official Church of Scientology Online Videos: What is Scientology, Scientologist Beliefs, Spiritual Healing with Dianetics (view on Google Sidewiki)