Twenty-third and penultimate letter of the Greek alphabet, is often used to letter Psi as a symbol of psychology. As every letter by itself means nothing. Meaning arises from the association of the letter Psi with the Greek word "Psyche", which originally had the meaning "butterfly" (in fact we can easily assimilate the shape of the letter with the stylized picture of a butterfly with wings deployed). Later the term came to be used with the meanings of "breeze", "breath", "mind" and finally "soul."

Such is the origin of the name "Psychology" (science of the soul) and the use of the letter Psi to represent it. The Greeks believed that when a person died and exhaled his last breath, the soul left the body as a butterfly flying. Greek mythology is the goddess "Psyche" and "Psyche" as a teenager with butterfly wings, the youngest of three daughters of a king of Asia, spoiled, insufferable character and fickle tastes.

In mythology Eros falls in love with Psyche ..

This myth represents the union between the spiritual and the physical to reach the elevation of the soul, to be whole beings.
A Psyche was represented with butterfly wings. The Greeks believed that when a person died and exhaled his last breath, the soul left the body as a butterfly flying and the body of the butterfly stroke is the Greek letter psi.

Currently, the butterfly has also been used with the meanings of freedom, peace, creativity, ideals, serenity, excitement, weakness, well .... The butterfly represents the existence and the need for adequate living conditions, both the physical environment, as the organism that inhabit them (including the deadly human), and in this sense, psychology is being, life, encouragement, progress , performances and social intellectual and political ecology.

Animals have been, with very high frequency, "raw material" conducive to symbolize human claims (real or perceived). The butterfly appears to meet the necessary requirements to represent the motives of psychologists.