Acharya Prashant explains that Shri Krishna defines ignorance not as the absence of knowledge, but as the presence of doubts arising from reliance on incomplete knowledge. Since all knowledge is external and limited, it can never provide total assurance, leaving the mind in a state of constant terror and uncertainty. The speaker emphasizes that our relationships and sense of security are often based on this fragile mental content, which Shri Krishna identifies as the root of ignorance. To live by the limited when the unlimited is available is the essence of an ignorant life.