Please don’t misunderstand me and think that I am trying to insist on the reality of dualism as a fundamental system at the metaphysical level. I think that it is far too easy for us as humans to impose a template of duality over the world, because:
1) Biologically we are each created by a mother and a father, and exist principally as one of two genders.
2) Biologically we each have a right and left side to our bodies and brains.
3) Terrestrially we revolve around a single star, and so experience periodic cycles of day and night, and summer and winter.
4) Have, in addition to this single burning star we revolve around, a single satellite revolving around us, so that temporally we exist through a sun-in-day and moon-in-night ever recurring cycle.
5) Geographically we are always caught by gravitational forces against a horizontal plane of land while extending upright into the air.
6) Symbolically, the human consciousness has developed within political and/or religious systems that have drawn lines between “us” and “them” or notions between what is good and bad or legal and illegal, as a way to regulate and control society.
One can continue to produce influential reasons for seeing the world through a cognitive map of duality, and explaining how similar systems became inscribed as a reality for human beings, but I think one can also discern the short-comings, limitations, problems and falsities that such a simplistic and generalized method of categorization leads to. One problem is that there are so many ways to divide things and events up. One might come up with a thousand binary categories and then place a thousand things or events in one of the two columns for each of the thousand categories, only to discover that each thing or event is a unique occurrence, an entity consisting of a unique set of overlapping categories, while none of these categories can offer anything other than a very small perspective, and the uniqueness of a multitude of categories becomes itself beyond categorization. Another problem is the contestable nature of placing an event or thing into either one or another category. Different minds will have different ideas on how to divide phenomena up, and the process itself denies or ignores any intermediate or gray area, or variations to a two-term system. Attempting to split the elements of the world up like this is obviously a very crude, nearly laughable, procedure, which we would probably be better to avoid or think beyond.
Still, it is a fact that there are many differences. And while it may be true that the human mind tends to assemble types that can be spread out along a spectrum and identified by their poles, it seems more true to assert: Difference exists. A multitude of instantiations of Difference exists. Somehow the fact of Difference is primordial, and built into the ground or the metaphysics from which reality arises.