16. All birds, that do not sing loud, are unhappy; No well-fed birds fail to sing loud.
__________
Taking "persons" as Universe; m="in the house"; x="John"; and y="having a tooth-ache"; represent
17. John is in the house; Everybody in the house is suffering from tooth-ache.
18. There is no one in the house but John; Nobody, out of the house, has a tooth-ache.
__________
[See pp. 68-70]
Taking "persons" as Universe; m="I"; x="that has taken a walk"; y="that feels better"; represent
19. I have been out for a walk; I feel much better.
__________