Concepts, concept change, imagination

Many concepts are empirically grounded.  Near and far might be defined for Asa by a Lego NXT ultrasonic sensor.  Push and pull might be defined for Asa by a Lego NXT or Vernier force sensor. etc. etc. Other concepts are at least partially nonempirical.  The concept of a unicorn, for example.  Asa may have seen pictures of horses and goats.  The concept of a goat will have a horn as one of its features.  (A feature being a concept stored on the next lower level of the Asa H hierarchy.)  Asa's various learning algorithms include things like vector interpolation, extrapolation, chaining, etc.  Asa may try to combine the features of  a horse with those of a goat, for example, and produce the concept of a unicorn.