Acharya Prashant explains that the feeling of unrest while reading scriptures like the Bhagavad Gita arises because we fail to see the unity between our internal world and the external material world. Shri Krishna categorizes nature into eight elements: the five physical elements (earth, water, fire, air, ether) and the three internal elements (mind, intellect, and ego). He classifies these together as 'lower nature' or 'Apara Prakriti'. The speaker emphasizes that our thoughts, emotions, and ego are as material and insentient as stones or water. We suffer because we mistakenly attribute consciousness to these material processes, such as intellect and emotions, which are essentially chemical and biological functions of the brain.