Father William
Parody structure
Carroll is responding to Robert Southey's 1799 poem "The Old Man's Comforts and How He Gained Them," which presented a sentimental old man dispensing wisdom. Carroll inverts this: his Father William is absurd, selfish, and refuses genuine engagement.
Logic inversion
The joke works through backwards reasoning: most people fear headstands damage the brain, so they stop. Father William does them more because he's convinced he has no brain left to damage. This is absurdist logic, not wisdom.
Salesmanship intrusion
Father William suddenly tries to sell ointment to his questioner mid-conversation. This breaks the expected mentoring tone and reveals his real character: opportunistic and indifferent to the youth's genuine curiosity.
Dismissal and threat
Instead of patience or wisdom, Father William ends with irritation and violence. "Be off, or I'll kick you down-stairs!" reveals he's been tolerating the youth's questions only because he had to, not from any paternal concern.