There are many different important types of duality that we encounter in our attempts to understand our surroundings. Some of the most fascinating are:

(A) Duality of what makes a human body unique:
(1) being composed of a particular group of physical particles; and
(2) having a particular organization.

(B) Duality of:
(1) what is the self; and
(2) what is outside the self, or other than the self
Note that it is possible to model reality without organizing it into “self” and “outside the self,” as the former can be seen as merely that set of feedback loops that the command structure, the “will,” has the most control over.

(C) Duality in the purposes of rules:
(1) to serve the purposes of the elites, particularly those who fashion the rules; and
(2) to serve somewhat utilitarian purposes to ensure the society is healthy, prosperous, stable, secure, and sustainable.

(D) Duality in the forms of experience of an event:
(1) the actual physical sensation of the event experience; and
(2) the model of the experience that forms in one’s mind and that is available to memory.

(E) Duality in human personality:
(1) humans are social animals, learning virtually everything they know from other humans, using terms and ideas from other humans to create their models of reality, and depending on other humans for emotional support and physical security; and
(2) humans also can act as individuals, striving to create new ideas and new models of reality while taking on new tasks that they determine for themselves.

Note: I intentionally left out the famous “dualism” of Rene Descartes regarding mind and body. I do not consider mind and body to be of a different nature.