Elemental: The Four Elements, Earth, Fire, Air, Water in Greek Philosophy and Jungian Psychology
From Ancient Greek Science and 
Philosophy to Ancient Sites Poetry
copyright 1998 by Tracy Marks
image from the Particle Adventure Home Page
http://www-pdg.lbl.gov/cpep/four_elem_ans.html
According to the Empedocles, a Greek philosopher, scientist and healer who lived in Sicily in the fifth century B.C., all matter is comprised of four  "roots" or elements of earth, air, fire and water.   Fire and air are outwardly reaching elements, reaching up and out, whereas earth and water turn inward and downward. 
In his Tetrasomia, or Doctrine of the Four Elements, Empedocles described these elements not only as physical manifestations or material substances, but also as spiritual essences.  He associated these elements with four Greek gods and goddesses - air with Zeus, earth with Hera, fire with Hades, and water with Nestis (believed to be Persephone): 
Now hear the fourfold roots of everything:
Enlivening Hera, Hades, shining Zeus
And Nestis, moistening mortal springs with tears.
In Empedocles' philosophy, the interaction of the four elements is influenced by the relationship between the two great life energies of Love and Strife: 
Empedocles explained that there are two great living forces in the universe, which he called Love (Philotês) and Strife (Neikos) and assigned to Aphrodite and Ares. According to Hesiod, the Goddess Love and the God Strife, offspring of Night (Nux), were ancient deities, predating the Olympians. The original Greek golden age was the Reign of Aphrodite, when all things were united and Love permeated the length and breadth of the well-rounded cosmic sphere. But Strife, as the River Styx surrounding the Sphere, broke its Unity, and cleaved the One into Many. It divided the four elements, which ever since combine and separate under the opposing actions of Love and Strife to produce the changing world with its manifold objects and qualities. As Heraclitus said, "Through Strife all things come into being." Empedocles said that Strife also divided the one immortal soul of Love into many individual souls, each comprising both Love and Strife in some proportion; these immortal souls are reborn time and again into mortal bodies, which are animated by mortal souls compounded from the four elements.
from Exercise for Unity by Apollonius Sophistes
http://www.mension.com/elements.htm
Another Greek philosopher/scientist who subscribed to the idea of four personality types was the physician Hippocrates. Rather than consider them to be "roots" or elements, he viewed them as bodily fluids or humors. Fire is akin to his conceptualization of blood (active, enthusiastic), earth to phlegm (apathetic and sluggish), air to yellow bile (irritable, changeable), and water to black bile (sad, brooding). 
 
In his online Bibliotheca Arcana, John Opsopaus includes several articles on The Ancient Greek Doctrine of the Elements. Here, he discusses theories related to the four elements as developed by both Empedocles and Aristotle. As further developed by Aristotle in his Metaphysics, these elements all arise from the interplay of the properties of hotness and coldness, and dryness and wetness. Fire (dry and hot) and water (wet and cold) are opposites, as are earth (dry and cold) and air (wet and hot). Each of the opposites was considered to have existed in an ideal form, apart from earth and in a mixed impure form, on earth: 
Aristotle explains that Moistness is the quality of fluidity or flexibility, which allows a thing to adapt to its external conditions, whereas Dryness is the quality of rigidity, which allows a thing to define its own shape and bounds. As a consequence Moist things tend to be volatile and expansive, since they can fill spaces in their surroundings, whereas Dry things are fixed and structured, since they define their own form.
Opsopaus points out the various associations made to the Four Elements by Empedocles and his Greek followers,  as well as their development in western mysticism, alchemy (3) and Jungian psychology: 
Most obviously there are the macrocosmic manifestations of the Elements, for example, the land, the sea, the sky and the sun. They are also connected with the sublunary spheres: Heaven, Earth, Abyss (the subterranean water) and Tartaros (the subterranean fire). There are also microcosmic manifestations, for example, as components of the human psyche (mental, astral, etheric and physical bodies).... The Elements also represent the stages in various processes of growth and transformation.... Finally, from the standpoint of Jung's psychology, the Elements (like the Gods) are archetypes; because they are structures in the collective unconscious, they are universal (present in all people). As archetypes, they are beyond complete analysis; they can be "circumscribed but not described"; ultimately they must be experienced to be understood.
from The Ancient Greek Doctrine of the Elements by John Opsopaus
http://www.cs.utk.edu/~mclennan/BA/AGEDE/Intro.html
 
Earth, for example, is cool and dry, passive and rigid, a principle of structure and materialization. Psychologically, it is therefore predominant in persons who focus extensively upon physical reality, and who may tend toward qualities such as perseverance, inflexibility, realism and pragmatism. 
Water, however, was originally the Primordial Chaos, associated with dissolution, union and transformation, and therefore with the goddess Persephone, who rules over death and rebirth in the Underworld, and whose lessons bring both tears of grief and tears of joy. Psychologically, water is likely to be the predominant element in people who tend to be flowing, flexible, oriented toward harmony or union, and inclined toward deep feeling. 
 
CONCLUSION
The Greek theories of the four elements, originally developed by Empedocles and expanded by Aristotle, have had a significant influence upon many traditions stretching into the 20th century - spiritual schools based upon alchemy, astrology, Jungian psychology (with its correspondences to thinking, feeling, intuition and sensation), Meyers-Briggs personality theory, and even Luscher's four-color personality profile. According to many mystics and transpersonal psychologists today, individual psychological and spiritual development is indeed related to the presence of and relationship ( the love/ harmony/ union or the strife/ opposition/ separation ) between the elements within the psyche. When two opposing elements encounter each other, they may neutralize each other, or according to alchemy and Jungian thought, lead to Coniunctio Oppositorum, the Conjunction of Opposites, a form of higher unity and transcendence of polarities. 
 
copyright 1998, 2006 by Tracy Marks
(Torrey Philemon of Ancient Sites)