Speakers usually employ the rhetoric of persuasion in order to appeal to their audiences. Martin Luther King Jnr. in his Letter From Birmingham Jail resorts to the aid of these devices to enhance the authority and reasonability of his utterances to strike the emotions of the segregationists he addresses who are fellow clergymen.
In this letter, King employs logos as a rhetorical strategy in the hope that he dresses it up with factual accounts of injustices meted out on the Negroes. He feels that the laws are unjust and as such, the people have the moral responsibility to disobey such laws. His strategy here is logos which he appeals to through definitions and literal and also historical analogies. King explains what just and unjust laws are and quotes St Thomas Aquinas for stamping the truthfulness and authority of his sentiments.(Luther,7)
He also borrows from lines of philosophy experts like St Augustine and historical evidences like the Declaration of Independence top add to his logos. Towards the end, he becomes sympathetically critical so as to arrest the emotions of the segregationists by taking them through the sufferings of innocent young and old negroes who have somehow adapted to the prejudices but are still fighting against them nevertheless.
Another aspect of logos King uses is the abstractness of language enabling him to appeal to the logicality of his course. When pressed to wait by the authorities, King responds that “wait” has almost meant the same as “never” for any delay in justice is the same as its denial. His informed opinions about the impending racial nightmare justifies the urgency for attention to his calls.
Luther, M. Why We Can’t Wait. New York: Signet Classics.2000 print