In Chapter 8 of The Chrysalids, Uncle Axel seeks to build David's self-esteem after the fears he has had. His mother's sister, Aunt Harriet, took her life because she had given birth to another Deviation. David was present when both his mother and father chastised Harriet and reproached her for her sin and her horrible idea for saving her deviant baby. David is thrust up against the Definition of Man and the chant "Accursed is the Mutant!" right in his own home.
David becomes very fearful and earnestly prayers at all times to have his deviant ability removed. It is in this condition of near-terror that David goes to help Uncle Axel, who helps him to see that having a deviation doesn't make him accursed and that there may be a great use for his unorthodox ability. Uncle Axel tells him a story about a "rusted mirror" that cheers David up and helps him to calm down and focus on hiding his ability.
Uncle Axel is similar to Angus Morton in that neither one of them really believes the extreme ideas represented by the Definition of Man, but both, in their own ways, keep their opinions from interfering with their lives in Waknuk. Also Uncle Axel understands that at one time, having a Definition of Man helped preserve a recognizable humanity even though they were and are surrounded by indescribable mutations in the Badlands and Black Coast.