Phil, I'll remind you of your own comment:

Incommensurate thoughts: People with different life-experiences are literally incapable of understanding each other...

Analogy: Take some problem domain in which each data point is a 500-dimensional vector. Take a big set of 500D vectors and apply PCA to them to get a new reduced space of 25 dimensions. Store all data in the 25D space, and operate on it in that space.

Two programs exposed to different sets of 500D vectors, which differ in a biased way, will construct different basic vectors during PCA, and so will reduce all vectors in the future into a different 25D space.

In just this way, two people with life experiences that differ in a biased way (due to eg socioeconomic status, country of birth, culture) will construct different underlying compression schemes. You can give them each a text with the same words in it, but the representations that each constructs internally are incommensurate; they exist in different spaces, which introduce different errors.

It seems entirely plausible that a person's appreciation of a piece of music depends strongly on all the music to which she's previously been exposed. Two different observers with different music-histories may have very different internal representations of the same piece of new music. A given piece of music may be well-formed or high quality in one representation, but not another.