11. If neither Aristotle nor Boole is a logician, there are no logicians. (Lx: x is a logician; a: Aristotle; b: Boole)

15. If everyone is sad, then no one is happy. (Sx: x is sad; Px: x is a person; Hx: x ls happy)
(x) Sx —>

17. If Cudworth is a logician and all logicians are bores, then he is a bore. (Lx: x
is a logician; Bx: x is a bore; c: Cudworth)

20. If any number is odd, then not every number is even. (Nx: x is a number;
Ox; x is odd; Ex: x is even)

F

3. If Darwin is not a biologist, then no one is a biologist. (d: Darwin; Bx: x is a
biologist; Px: x is a person)

8. If everyone is wise, then no one is a fool. (Px: x is a person; Wx: x is wise;
Fx: x is a fool)

14. Either no one is wise or Solomon is wise. (Px: x is a person; W’x: x is wise;
s: Solomon)

17. At least one nonphysical thing exists given that God exists. (Px: x is physical;
G: God exists)