The (almost really) Complete Works of Lewis Carroll

First Paper on Logic

Source: printed 1886

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I.

State each of the following in 3 equivalent forms:—

(1) There are no perfect men.
(2) Some apples are unripe.
(3) No pigs can fly.

II.

Taking x = ‘good riddles,’ and y = ‘hard,’ interpret:—

(1)0. (2)10.

(3)11. (4)00.

III.

Break up each of the following into its 2 component propositions:—

(1) All judges are just.
(2) All good children are happy.
(3) All old and sickly men are fretful and troublesome.

IV.

Taking x = ‘cakes,’ and y = ‘wholesome,’ represent, with diagrams like those in Qu. II, the following propositions:—

(1) Some cakes are unwholesome.
(2) There are no wholesome cakes.
(3) There are no cakes in existence.
(4) All cakes are wholesome.

V.

Taking x = ‘diligent students,’ and y = ‘successful,’ represent in like manner:—

(1) No diligent students are unsuccessful.
(2) All diligent students are successful.
(3) There are some diligent students.
(4) There are some diligent, but unsuccessful, students.

[June, 1886.]