Nor can anyone acquire new and different knowledge of anything under the force of an injunction it he has already known it as different through a valid means of cognition. Even if he thinks of it differently (e.g. thinks of woman as the sacrificial fire, (cp. Chand:V.viii.l) under the conviction that he is enjoined to do so, this does not amount to knowledge, but only to imaginative mental activity. And if a thing that had been properly known through a valid means at cognition suddenly began to appear different of its own accord, that would simply he error. (B.S.Bh.III.ii.21)(from The Method of Vedanta 134/5 by Swami Satchianandendra)
(Swami S. Note)
Let us suppose that a person, who has know something in one way through a valid means of cognition, meditates upon it as something different in obedience to a Vedic injunction. The point here made is that genuine knowledge will remain unchanged by this, even though the person is obeying a vedic injunction. For instance, if one is enjoined to see vishnu in a stone image, that does not abolish the notion that it is a stone image. The notion of vishnu is the product of subjective human endeavour. It is only a piece of meditation, and so a piece of mental activity. If, however, there were only the stone image, and through darkness or some other obscuring factor there arose other ideas of it, such as the notion that it was a man, that should be considered simply as error.
If, as is the case with most people, one has come within the purview of vedanta through the mediation of a teacher then the confirmation that one has experienced will become virtual sabda or a valid means of knowledge. That remains the touchstone in contrast to the mental understanding of even the highest teaching. The Master has become the portal. May I suggest that the presence of the Master becomes subtilized as the Seeker progresses. Even Ramana was first drawn by Arunachala Shiva. His atma vichara method or who am I inquiry is energized by his presence.