Sage Sri,Sankara said:- Talk as much philosophy as you like, worship as many gods as you please, observe ceremonies and sing devotional hymns, but liberation will never come, even after a hundred aeons, without realizing the Oneness.
People consider themselves to be knowledgeable because they have read books and well informed about the subject. But all these accumulated knowledge is not wisdom. One can’t get non-dual wisdom from accumulating knowledge.
Whether the knowledge accumulated are scriptures or something from most recently published books are mere pointers to truth but not wisdom. First, whether we're aware of it or not, as one reads he is imposing his own cultural conditioning, biases, experiences, and prior knowledge onto what he is reading; this is how his brains work. He “makes sense" of new things by associating them with things he already knows.
Most of the time, this is useful. But if the "new thing" is utterly different from anything one has been exposed to before, he is almost certain to distort it to make it fit into pre-existing conceptual boxes. So much of knowledge is about changing perspective, but that's hard to do when one is twisting the knowledge around to fit the perspectives he is already having.
Regarding the Vedic scriptures, most of us are reading English translations of texts written in Sanskrit or some other language from long ago and far away. Because these languages are enormously different from English, literal translations into sensible English are not possible. So, what we're reading often is as much the translator's interpretation as it is a translation. Often in English syntax requires that the translator construct phrases that aren't in the original. And to do this, the translator must draw upon his own cultural conditioning, biases, experiences, and prior knowledge. That becomes apparent if one gets the chance to compare several translations of the same text. Sometimes the differences are significant.
One should not accept the scriptures as proof the way religionists hold as ultimate truth without verification. Scriptures may be useful to validate a path already traveled, but not much good as a roadmap to the final destination.
Self-knowledge or Brahma Gnana or Atma Gnana does not depend on reading, or by following the path or teacher, or through scriptural studies or by practising yoga or by leading a religious oriented life, but it comes by perfect understanding, assimilating realizing the fact that, the self is not physical but self is consciousness (soul).
Self is consciousness, by mistaking self to be a physical entity, the ignorance is born. One thinks one is imprisoned within the physical body; but in reality the consciousness is within the three states but it is without the three states. One has to mentally grasp the existence of the consciousness. One has to realize the Consciousness is the true self, by knowing it without the three states to realize its formless true nature.
The moment one knows that the mind is consciousness, and then there is no ignorance. When there is no ignorance than there is no duality. When there is no duality then there is no illusion. When there is no illusion then there is only reality, which prevails as non-dual existence.
Consciousness is of the nature of knowing. Existence of god means one is thinking of god but gods existence is depends on consciousness. It is a duality which causes the ignorance. Thus one has to inquire into the nature of the mind (duality or universe) first, after understanding the nature of the mind, and then only he has to proceed further to understand the consciousness. By understanding “what is the mind? And “what is the substance of the mind?” is the only way to acquire Self-Knowledge. Until and unless one knows the consciousness, he has only the mind, which is the whole physical existence (man+ universe).
If one goes beyond mind, it is nothing but consciousness. Inside and outside the mind everywhere is only consciousness.
When the mind manifests as universes itself it is the consciousness that shines. Consciousness is the witness and what appears is also consciousness. Whatever has appeared is appeared on its own. Man and the world are within that appearance. The one which is aware of the appearance and disappearance of the appearance is not the waking entity, because waking entity is within that appearance. Therefore, viewing the appearance on the base of the waking entity is the cause of all confusion. Therefore, one has to mentally trace the formless knower of the appearance, to realize the waking entity is not the knower of the appearance but the formless consciousness (soul) is the knower of the appearance dual and non-dual experiences.