Incommensurate thoughts: People with different life-experiences are literally incapable of understanding each other, because they compress information differently.

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. When they reason on their compressed data, they will reach different conclusions, even if they are using the same reasoning algorithms and are executing them flawlessly. Futhermore, it would be very hard for them to discover this, since the compression scheme is unconscious. They would be more likely to believe that the other person is lying, nefarious, or stupid.