Aedes,
You have me toying with the idea, but I am not sure your right as yet, although the judgement or evaluation is a biological statement, the terms themselves, must have some catagorical function. They define largely what is acceptable to the body, and being catagorical in this sense they are mutually defining. It is true that a sensation might fall in midrange and thus not be categorized as either, but closer to a mundane experience, this to would ultimately be filed between good and bad, mundane not being particularly good nor particularly bad. I think it comes down to pleasure, displeasure, if you do not know what pleasure is, you could not know displeasure, intellectually at anyrate, biologically yes, the distinction would never the less be experienced.