Shankara's Concept of Ignorance

CULTIVATING KNOWLEDGE
The wise have explained that one result is derived from the culture of knowledge, and that a different result is obtained from the culture of nescience.
  ~Sri Ishopanishad, Mantra Ten

For one who lives a hedonistic life, a life in which nescience is cultivated, the results are envy, anger, greed, impatience, disrespect for others, anxiety, depression, hatred, ever-increasing lust, forgetfulness, frustration, dissatisfaction, duplicity, fear of death, and so on.
Science of Identity Foundation – Siddhaswarupananda
Shankara’s Concept of Ignorance

MICHAEL: What about Shankara’s explanation of the illusory energy itself? Is ignorance a part of Brahman, or is it separate from Brahman?

TEACHER: This is a subject which Shankara never treated in depth in any of his writings.19 Most probably this is due to the fact that he couldn’t develop a logical explanation for the existence of ignorance without contradicting the Upanishadic definition of Brahman, or weakening his own explanation of how ignorance brought about the existence-or apparent existence, as Shankara would say-of the individual souls and the cosmic manifestation.

The dilemma is this: Is ignorance real, or is it simply an apparent reality? Shankara could not openly declare that ignorance is an actual reality, since to do so he would have had to admit either (a) that ignorance existed independently of the Supreme Brahman, or (b) that ignorance is part of the Supreme Brahman. He could not admit point (a), because to do so he would have had to acknowledge the existence of a reality other than Brahman. Yet the Upanishads very clearly declare that Brahman is the only reality.20 Therefore, if he admitted ignorance as a reality separate from Brahman, he would have been in contradiction to the Upanishads. Neither could Shankara admit point (b), since to do so would be to challenge the omniscience of the Absolute Truth (as he saw it). Therefore, Shankara chose to explain maya as an apparent reality. That made it very difficult for him. After all, if maya does not really exist-if it’s just an apparent reality-how does it affect the Supreme Brahman? How is it responsible for the existence of the cosmic manifestation and the innumerable living entities? So it is not surprising that Shankara does not attempt to explain the existence of ignorance. To do so would probably lead to an infinite regress of explanations. In other words, just as the apparent reality of the jivas and the world is explained in terms of ignorance, ignorance (also being an apparent reality) would have to be explained in terms of some other power or force which brought it into existence. And this force would in turn have to be explained in terms of another force which was responsible for its existence, and so on, ad infinitum.

MICHAEL: How about the manner in which ignorance acts upon the Supreme Brahman? Does Shankara attempt to explain this anywhere in his writings?

TEACHER: Not to my knowledge-at least, not in a connected manner, not in depth. There are places, however, where he indicates that the cosmic manifestation and the jivas have been brought about due to the desire of the Supreme Brahman. This idea has been developed more systematically by other Mayavadis. I’ll read you a verse in this connection from Shankara’s Aparokshanubhuti, and also the commentary on that verse by Swami Vimuktananda, a contemporary Mayavadi philosopher. Shankara states:

The non-dual (Brahman) that is bliss indivisible is denoted by the word “time,” since it brings into existence, in the winkling of an eye, all beings from Brahma downwards.21