“Our essence of Mind is intrinsically pure. If we knew our Mind perfectly and realised what our Self-nature truly is, all of us would be enlightened.” (Bodhisattva Sila Sutra - ca 450 BC)
At around the same time the concept of Selfrealisation bloomed in the philosophical circles of Greece under the heading “know thyself”, and became famous through Socrates who claimed “Knowledge is inherent in man, not outside. Wisdom is learning to recollect”
In the Orient this was apparently taken seriously, as – particularly in India, Tibet & China – it brought about a variety of teachings & schools as well as methods & approaches attending the different needs and temperaments of the aspirants of Selfrealisation.
That “know thyself” made it in the Occident barely beyond philosophical exercises, is probably because it established in the same period the ratio of dualism which subjected knowledge to the feedback mechanism of the intellect. This is not to say that eastern aspirants do not use intellectual techniques, but they are taught how far to utilise them (which is not all the way to the beginning) whereas western thinkers think that they have to think all the way to the end.
I believe ‘know thy self’ is applicable to two fundamental levels, i.e.
Humanity level
Individual level
The universal principle is, for any knowledge of anything to be applied effectively, humans must dig into the roots of those things.
As it is obvious, note the pursue of Science into the depths of the physical world & its systems and the more Science dig into, the move power humans can harnessed, e.g. atomic power in contrast to power from organic fuel.
Thus it is very rational, along with the above principle, the human person must dig into its own roots to ensure knowledge is applied effectively and wisely.
Actually, humans has taken the steps from millenniums ago to know thy self, i.e. the physical self, i.e. the anatomy and human organic systems within.
Humans has also strove to dig into the mental self, i.e. psychology, via the black-box approach.
The last bastion of knowledge humanity need to know-thyself is the workings of the brain and knowing precisely how they manifest in the range of human behaviors.
Note humanconnectomeproject.org/
It is true the Eastern philosophers has dug dig into the human self since millenniums ago, they could only do it on the ‘black-box’ approach.
What has been going on in the ‘West’ at present is scientists are digging right into the black-box to understand its internal mechanism to the finest details. E.g. the above note humanconnectomeproject.org/ [ongoing] and the Human Genome Project [completed].
While humanity as a whole strive to know more and completely of the human-self, the individual[s] must at the same time ‘know thy self’ which need to overridden by the Philosophy of Morality to ensure they do not end up with evil and violence.
Atman is a person’s true self, which is infused with or is entirely coterminous with the universal spirit of Brahman, thus lying beyond the phenomenal, changing reality we perceive. It is vaguely similar to the Western concept of the soul, as each person “possesses” or partakes of the atman, but it differs from a soul in that the atman is not entirely unique to an individual; some Hindus believe that all individual atman are joined to the separate and superior Brahman, while others believe that each individual atman is Brahman itself.
The idea of atman merging with Brahman existed within the Vedas.
Whilst the idea of atman is useful, the idea of atman is not highly effective in the management of sufferings of primal nature.
Buddhism-proper did a 180 degree paradigm shift by introducing the idea of ‘an-atman’ or anatta [pali], i.e. there is no absolute atman nor absolute Brahman.
The point is, with the idea of atman and Brahman, there is still something that the mind will attach to.
Attachment leads to desire and clinging.
If there is a threat of detachment, the mind suffers, i.e. do not want to let go, thus the manifestation of sufferings.
If the idea of atman and Brahman is dissolve, then there is nothing to be attached to, but obviously the person is still around to live, survive and progress optimally with effective spiritual practices.
This is where Buddhism-properly abolished the idea of atman and Brahman totally but yet interact with reality as it is in the optimal Middle-Way.
There is the idea of neti-neti and if applied totally to atman and Brahman unconditionally, that would be similar to Buddhism-proper.
Find yourself to be the center of your own Universe.
Explore the Nature and Powers of your own Being. This includes everything which is, or can be for you: and you must accept everything exactly as it is in itself, as one of the factors which go to make up your True Self. This True Self thus ultimately includes all things so ever: its discovery is Initiation (the travelling inwards) and as its Nature is to move continually, it must be understood not as static, but as dynamic, not as a Noun but as a Verb.