Acharya Prashant explains the fundamental difference between personality and individuality by using the concept of the mind. He describes the common state of the mind as a 'divided mind,' which he illustrates as a circle partitioned into various sectors. These sectors represent external influences such as parents, education, media, society, friends, and religion. He asserts that what people typically call their 'mind' is merely a storehouse of past impressions and experiences where multiple external forces hold control. This fragmented mind makes a person a slave to many forces, leading to constant internal conflict, suffering, and a lack of excellence because energy is never fully focused in one direction.