In this essay I shall be concerned with declarative, interrogative and imperative sentences. What do they mean ? Under what circumstances may they be said to be true, and under what circumstances false? When is their utterance an honest remark and when is it a lie?
Such an enumeration of questions might suggest that I hold other speech forms than the declarative sentence to be classifiable as true or as false. Such indeed is the case. I hope to show why and how interrogatives and imperatives, as well as declaratives, are to be classified as true or false.
Interrogatives, imperatives, truth, falsity and lies
by Henry S. Leonard
Philosophy of Science (1959)
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