What is mental inflation? It is joy and rapture associated with passion-lust because one sees as excellences the prospect of a long life and other fragile good things by trusting in one's youth and good health. Its function is to provide a basis for all basis and proximate emotions.
It is an inflated mind which is full of joy and rapture in view of health, abundance of pleasure, etc. It is the root of unconcern by generating all other emotions. The Adhyasayasamcodansasutra states,
An inflated mind is the root of unconcern.
Never treat a poor bhiksu with contempt
Or you may not find salvation in an aeon.
This is the orderly procedure in this teaching.
The Suhrlleka states,
Look at the vain glory of your social status and appearance,
Your learning, your youth, and your power as your enemies.