Maslow's hierarchy of needs / pyramid of existence

    1st) Physiological: to fulfill hunger, thirst, bodily comforts, etc.;
    2nd) Safety/security: to be out of danger;
    3rd) Belonginess and Love: to affiliate with others, be accepted;
    4th) Esteem: to achieve, be competent, gain approval and recognition;
    5th) Cognitive: to know, to understand, and explore;
    6th) Aesthetic: to find symmetry, order, and beauty;
    7th) Self-actualization: to find self-fulfillment and realize one's potential; and
    8th) Transcendence: to help others find self-fulfillment and realize their potential.

    (NOTE: not experimentally verified)