Trevor-Roper's Ten Commandments of Writing

British historian Hugh Trevor-Roper composed in 1971 his Ten Commandments regarding writing.  These were apparently included in his memorial service on March 8th, 2003 after his passing on January 26th, 2003.  

1. Thou shalt know thine own argument and cleave fast to it, and shalt not digress nor deviate from it without the knowledge and consent of the reader, whom at all times thou shalt lead at a pace which he can follow and by a route which is made clear to him as he goeth.

2. Thou shalt respect the autonomy of the paragraph, as commanded by the authority and example of the prophet Edward Gibbon, for it is the essential unit in the chain of argument. Therefore thou shalt keep it pure and self-contained, each paragraph having within it a single central point to which all other observations in it shall be exactly subordinated by the proper use of the particles and inflexions given to us for this purpose.

3. Thou shalt aim always at clarity of exposition, to which all other literary aims shall be subordinated, remembering the words of the prophet commandant Black,  ‘clarté prime, longueur secondaire’. To this end thou shalt strive that no sentence be syntactically capable of any unintended meaning, and that no reader be obliged to read any sentence twice to be sure of its true meaning. To this end also thou shalt not fear to repeat thyself, if clarity require it, nor to state facts which thou thinkest as well known to others as to thyself, for it is better to remind the learned than to leave the unlearned in perplexity.

4. Thou shalt keep the structure of thy sentences clear, preferring short sentences to long and simple structures to complex, lest the reader lose his way in a labyrinth of subordinate clauses; and, in particular, thou shalt not enclose one relative clause in another, for this both betrays crudity of expression and is a fertile source of ambiguity.

5. Thou shalt preserve the unities of time and place, as commanded by the high priest Nicolas Boileau, placing thyself in imagination, in one time and one place, and distinguishing all others to which thou mayest refer by a proper use of tenses and other forms of speech devised for this purpose; for unless we exploit the distinction between past and pluperfect tenses, and between imperfect and future conditional, we cannot attain perfect limpidity of style and argument.

6. Thou shalt not despise the subjunctive mood, a useful, subtle and graceful mood, blessed by Erasmus and venerated by George Moore, though cursed and anathemised by the Holy Inquisition, Pravda, and the late Lord  Beaverbrook.

7. Thou shalt always proceed in an orderly fashion, according to the rules of right reason: as, from the general to the particular, when a generality is to be illustrated, but from the particular to the general when a generality is to be proved.

8. Thou shalt see what thou writest; and therefore thou shalt not mix thy  metaphors. For a mixed metaphor is proof that the image therein  contained has not been seen with the inner eye, and therefore such a  metaphor is not a true metaphor, created by the active eye of  imagination, but stale jargon idly drawn up from the stagnant sump of  commonplace.

9. Thou shalt also hear what thou writest with thine inner ear, so that no outer ear may be offended by jarring syllables or unmelodious rhythm;  remembering herein with piety, though not striving to imitate, the  rotundities of Sir Thomas Browne and the clausulae of Cicero.

10. Thou shalt carefully expunge from thy writing all consciously written purple passages lest they rise up to shame thee in thine old age.