Every (person) has two completely separate parts, as if it were two different people.  These are ... essence and ... personality.  

Essence is I - it is our heredity, type, character, nature.

Personality is an accidental thing - upbringing, education, points of view - everything external.

Essence does not change.  All the material constituting your personality may be completely changed artificially or accidentally with a change in your surrounding conditions and place... When we speak of development and change, we speak of (personality). 

The point is to reestablish what has been lost, not to acquire anything new.  This is the purpose of development.  For this, one must learn to discriminate between essence and personality, and to separate them.  When you have learned to do this, you will see what to change and how.

GI Gurdjieff  March 1929 "Essence and Personality" in Views from the Real World (1973: 133-135).