Categories: How Far Back Should One Go?

During Wednesday's class, we discussed the existence of mimesis in literature.  While all the participants in the discussion appeared to agree that at least some mimesis is present in every literary work, the question of degree caused some disagreement.  Some of the participants argued that literature is entirely mimesis, because every concept expressed in it has been expressed before, or stems from real life, with very little variation.  However, if this is true of literature, why should it not be true of everything else as well?  If variation and combination of concepts has no impact on originality, then how can one distinguish between, well, anything?  Let me attempt to illustrate the problems with this theory:

There are two mugs, one blue and one indigo.  Apart from that they are identical.  Does the color distinction count?  Not according to the theory above.  We can group both the mugs into the category "mugs with colors in the cool side of the spectrum."  But now let us remove the indigo mug and introduce a new, red mug.  This category is no longer valid!  Does that mean that one of the mugs is categorically different from the other?  No it does not - the problem is easily remedied.  We shall simply expand the category to "mugs".

Now let us take away the red mug and bring in a wine bottle.  The "mug" category no longer applies, but that is no problem, we can just expand the category to "liquid-holding vessels."  Next, we will change the wine bottle to a chair.  Now the category is "inanimate objects made by and used by humans."  The chair is gone and we bring in a rock - it and the blue mug are both "inanimate objects."  We can get rid of the rock and replace it with a porcupine - an "material object."  The porcupine is replaced by a thought.  "Thing" is the category.

There is no limit to how far we can expand categories.  We can even create nonsensical compound categories like "broose" if we so choose.  Where do we draw the line?  Unless we wish to call absolutely everything in or out of existence a "thing", we will always be making some kind of possible arbitrary distinction.  Why should literary concepts be exempt from this?