Many of the fourfolds presented here are roughly a combination of two dualities, a double dual if you will. Their diagrams could be considered as a crossed pair of rectangular cards, with each card showing a single pair of opposites. If one creates cards for every unique and important dual, new juxtapositions not thought of previously may be revealed by random and spontaneous association.
Of course many fourfolds cannot be reduced to the simple sum of their parts, or even the sum of their pairs. All four concepts often ramify themselves and each other due to binary, tertiary, and quaternary relations. Then the fourfold is greater than its individual constituents.
For example, the Four Elements are more than the opposite pairs of Air and Earth, Fire and Water. In Hjelmslev’s Net, Substance and Form combines with a superficially similar Content and Expression. However, above is an example of what I am striving for when Space and Time is combined with Matter and Energy.
Below is a list of dualities that might be used to create a useful set of cards. Some duals will come from fourfolds mentioned here but others will be new. Dualities or dichotomies are usually included in lists of opposites or antonyms, although they are usually more philosophical in nature.
Fourfolds that cannot be readily divided into two duals may by presented by square cards, perhaps called “trumps” or “major arcana” (or perhaps even “arcana quadra”). If cards are picked randomly but placed by choice, the rules of such actions must next be determined.
List of Duals (alphabetic):
Actual, Potential (Actual, Possible)
A Posteriori, A Priori
Begin, End (Start, Stop)
Chaos, Order (Discord, Harmony)
Difference, Sameness (Distinction, Similarity)
Disease, Health (Sick, Well)
Emotion, Reason (Irrational, Rational)
Found, Lost (Find, Lose)
Hidden, Revealed (Invisible, Visible)
Inside, Outside (Internal, External)
Me, You (Them, Us)
Object, Subject (Objective, Subjective)
Private, Public (Personal, Social)
Profane, Sacred (Secular, Spiritual)
List of Trumps:
Air, Earth, Fire, Water
Cold, Hot, Dry, Wet
East, West, North, South
Fall, Winter, Spring, Summer