Yoga Sutras of Patanjali translated by Yogi Kalinath - Chapter 2, Verse 3
Pada 2, Sutra 3
Ignorance, egoism, attachment, aversion and clinging to life are the root causes of affliction.
What Rishi Patanjali lists here are the 5 afflictions that blocks one from becoming Self-realized. They are in fact listed in the order of impacting significance. Ignorance (avidya) is the root cause of all the other afflictions. By ignorance is meant unawareness in total or in lapse of our true nature as spirit souls which in turn gives rise to egoism (asmita), the concept of the doer. From egoism, one develops attachment (to what is considered attractive to the ego) and aversion (to what is repulsive to the ego). By this time one is truly enmeshed in duality with the accompanying fear of death and hence the clinging to life.
Ignorance and egoism are intellectual afflictions (neo-cortex), attachment and aversion are emotional afflictions (mammalian brain) while clinging to life is an instinctual affliction belonging to the oldest part of our brain (the reptilian brain).
Yoga and Tantra aim to integrate the functions of the triune brain in order to transcend their limitations and attain to an expanded state of conscious awareness (Samadhi).