The one River that springs up in Eden (which represents Christ, the Living Waters, the Logos, the source of grace) divides into four as it enters the Garden that God has made as a home for Man. Thus the Garden of Eden is fourfold, it has the four directions (West, South, East, North), which correspond not just to the four gospels but to the four letters of the divine Name, the four faces of the Cherubim, and the four arms of the Cross.
Saint Ambrose compares the four Rivers of Genesis 1:10-14 to the four Cardinal Virtues: “The Pishon which flows over gold is Prudence, the Gihon which bathes Ethiopia (whose name signifies impurity) is Temperance, the Tigris (in Hebrew the swift) is Fortitude, and the Euphrates (the fertile) is Justice” (cited in Emile Mâle, The Gothic Image, 110 fn.). St Augustine follows Ambrose in this, and so does St Bonaventure.
In the classical view, there are also four main types of explanation (Gk: aition) that we can give for things in general: final, formal, efficient, and material. The final cause is what they are for, or how their nature fulfils itself. The formal cause is the inner shaping idea that makes them what they are. The efficient cause is what brings something about, or makes it do what it does, or be what it is. The material cause is simply what it is made of. If we follow the same Augustinian/ Bonaventuran tradition, we arrive at the following list: 
TEMPERANCE – Material cause – Finding our starting point, stable base
FORTITUDE – Efficient cause – Generating the energy we have available
PRUDENCE – Formal cause – Tracing our path to the final goal
JUSTICE – Final cause – Arriving at the goal we are striving for
 Emma Therese Healy, Saint Bonaventure’s Artium Ad Theologiam (Franciscan Institute, 1955), p. 94.
To be continued...