“Things equal to the same thing are equal to each other.”
“Trees grow in direct opposition to gravity.”
“Honesty is the best policy.”
“A stitch in time saves nine.”
Because the indefinite proposition is so frequently of a general nature, it is sometimes classed as general rather than indefinite.
Sir William Hamilton would class the indefinite as an indesignate proposition.
(2) Grammatical Sentences.
The grammarian divides sentences into five kinds; namely, declarative, interrogative, imperative, optative, exclamatory. But logic recognizes only the declarative, as it has already been seen that the four logical types are declarative in nature. A logical proposition, then, is always a sentence, but all sentences are not logical propositions. The four kinds of sentences which are not logical propositions may be usually reduced to one of the four types as the attending illustrations will indicate:
| Illogical | Logical |
| Interrogative. Do men have the power of reason? | The question is asked, Do men have the power of reason?[7] (A) |
| Imperative. “Thou shalt not steal.” | All men are commanded not to steal, or you are one who should not steal. (E) |
| Optative. “I would I had a million.” | I am one who desires a million dollars. (A) |
| Exclamatory. “Oh, how you frightened me!” | You are one who frightened me. (A) |
(3) Individual Propositions.