In this essay, I propose that Korzybski's general semantics principle "nonidentity" expresses a fundamental feature of Universe, human existence, and evaluations, including "epistemology." "Non-identity" can be considered a scientific theory (testable) stating that "no two things are the same in all respects." (In terms of structural change, and changing relationships, "a 'thing' is not even identical with 'itself.'") Difference precedes similarity. We evaluate things as being the same by ignoring differences. And we interact in a world of differences through neuropsychological processes involving pattern recognition. At conscious levels, pattern recognition includes relative invariance under transformation, fractals, structural similarity, metaphors, similes, theories, and so on.
I do not elaborate on relations between non-identity and epistemology, but propose that epistemology must ultimately be based on a premise of non-identity (and non-allness) if what we "know" and understand is not treated as identical with what is being known or understood, or accepted as all that can be known or understood.
We are aware of different things, and to emphasize this differential awareness, we give things different names. We also note that things occupy different positions. I think it is important to emphasize here that if two things occupied the same position we would not be able to differentiate the one from the other; we would not be able to say, "Here is this one, and here is the other." From this, it seems reasonable to make a generalization that no two things can occupy the same position. The question arises: "What's going on between things?" As we did not see molecules of air, waves of energy, or other substances in the interval between things, we assumed that there was nothing substantial there, and so we called this "betweenness"--this interval of seemingly "no thing"--"space."
It is worth emphasizing that our habitual and indiscriminate use of labels, names, and symbols facilitates identification. Things, situations, objects, individuals, groups, etc., change--despite our continuing to refer to them with the "same" names and labels. A label or name is not what is being labeled or named. We can minimize instances of our labeling identification habits and our tendency to ignore change and differences by remembering to apply the general semantics devices of indexing, chain indexing, and dating. For example, car (1), with a particular name, is not car (2) with the same name. In international affairs involving treaties and agreements, the government of a country at time (1) is not the same government of that country at time (2). War (1) at time (1) is not war (1) (the same war) at time (2). War 1914, is not war 2008. Generally, anything with a name (X) is not the same thing at some other time (due to changes) and is not the same thing as some other thing with the same name (X). We create problems for ourselves when, in treating others, situations, etc., we focus only on their names and labels while ignoring change, time, and operational relationships.
In some dictionaries, "space" is defined as the distance, expanse, or area between, over, within, etc., things. Here is what I am proposing: We could think of the word "space" as a label for "the totality of intervals between positions--including whatever exists in these positions." We assume there are no empty spaces. In other words, there is no location where there is nothing. Following this, things, objects, light waves, electromagnetic waves, and so forth, could be considered not as existing in space, not as occupying space, but as different expressions and configurations of space. And furthermore, these diverse space configurations--existing at different energy levels and densities--penetrate, destroy, displace, merge, interact, etc., with each other in diverse ways, thereby creating other space configurations and expressions. …