This piece was originally conceived as a progression from the simplistic to the complex.  After the first few sketches it became clear that reversing the progression would be more effective.  The distinction between simplicity and complexity is represented in this piece by use of only one motive, simple and use of four motives, complex. 

Distillation is presented as a lecture by the clarinet.  In the beginning, all four motives are presented and discussed, and then three motives, two until, in the end, there is just the one motive.  Throughout the piece, the final motive is emphasized, as being most important so that it should be no surprise that it concludes the discussion.