By which that knowledge of the non-Self as not existence, but the Self as existence
Then this knowledge, placed down like the reality of the snake and the rope.
Commentary
In this verse knowledge shines forth as an emanation of illusive relativity, despite the fact that knowledge dispels ignorance, like when comprehending the snake in the rope illusion. Knowledge is the reverse of non-knowledge or ignorance, thus forming a pair of relative opposites. In the spiritual texts we are told over and over that in order to attain the Absolute one must go beyond the pairs of opposites. This is why the sage has included knowledge under the category of illusive relativity. Here is what the Maitri Upanishad (VI.30) says: "When the five (sense) knowledges cease, together with the mind, and intuitive judgement stirs not, this they say is the Supreme Path."
The Upanishads also speak about a higher and lower knowledge. (See Mundaka Upanishad I.4) Higher knowledge is the knowledge of the Absolute, while lower knowledge is the relative knowledge of things and concepts imposed by the mind on the mind. This is the type of knowledge that Narayana Guru refers to.
The Goddess Sakti is illusive relativity and She has the power of deluding as well as taking one over illusive relativity. She binds and is also the giver of spiritual freedom. She is also the Goddess of Siva united to Him. She is also the Supreme Absolute, and Siva is one of Her 'realities'. In the Sanda Purana the Supreme Goddess is described as follows: "She who has assumed the energizing aspect of illusive relativity, who is connected with one's consciousness, who is intellect, without attributes, self-luminous, unchangeable, supreme wonder-joy, is also the cause of the destruction of the cyclic phenomenal world."