Symbolic Logic

by Lewis Carroll

Univ. “persons”; m = enthusiastic; x = doctors; y = you.

xm₀ † y₁m′₀ ¶ y₁x₀ [Fig. I (α).

Conclusion right.

2. Dictionaries are useful;
Useful books are valuable.
Dictionaries are valuable.

Univ. “books”; m = useful; x = dictionaries; y = valuable.

x₁m′₀ † m₁y′₀ ¶ x₁y′₀ [Fig. I (α).

Conclusion right.

3. No misers are unselfish;
None but misers save egg-shells.
No unselfish people save egg-shells.

Univ. “people”; m = misers; x = selfish; y = people who save egg-shells.

mx′₀ † m′y₀ ¶ x′y₀ [Fig. I.