Codex on Aristotle's Doctrine of the Mean

When I first studied the Nicomachean Ethics, I did so with the help of Urmson's wonderful book Aristotle's Ethics (1988), which surprised me with its strictures against interpreting the doctrine of the mean as a simple thesis of moderation.  Surely, I thought, no one could have read that into II.6.  Now, six and a half years later, I've had a glimpse of what Urmson meant – in the pages of an Inspector Morse novel:

“Morse skipped his way along [the report].  ‘… would suggest a period of between 72–120 hours before the body was discovered.  Any greater precision about these time limits is precluded in this case…’  As in all cases you ever have, muttered Morse.  He had never ceased to wonder why, with the staggering advances in medical science, all pronouncements concerning times of death remained so disconcertingly vague.  For that was the real question: when had Quinn died?  If Aristotle could be believed (why not?) the truth would probably lie somewhere in the middle: 94 [sic] hours, say.”

By coincidence, I was only reading this because of a sloppy piece of academia.  In Twentieth-Century Crime Fiction (2005), Lee Horsley, comparing the relationship between the authors and readers of detective fiction to that between the setters and solvers of cryptic crosswords, promised me that “Colin Dexter also gestures towards parallels between the mystery story and the cryptic crossword in The Silent World of Nicholas Quinn (1977), which involves Inspector Morse with a suspect who is a crossword-setter called Daedalus.”  Alas, this turns out to be an embellishment from Julian Mitchell's TV adaptation (1987), which made Ogleby a more interesting character.

Mervyn Peake's use of ‘must have’

I've just finished Titus Alone, the black sheep of the Gormenghast trilogy.  Peake's command of the language is impressive, despite the erratic punctuation, so I was especially intrigued by his peculiar use of the modal must in phase-modified clauses, that is, his use of ‘must have V-en’.  This form of words usually encodes an inference as to fact, as in Withnail's ‘What happened to my agent?  Bastard must have died.’  But now look at these (pagination from 1998 Vintage editions):

Titus Groan
‘The sky was overcast and had he not made this same journey through the darkness a thousand times he must surely have lost himself in the night.’  (The Library, p. 206)

‘Her fever had raged, and but for the care with which the old man watched over her she must surely have died.’  (Farewell, p. 357)

‘Had the flesh, the fibres, and the bones of the chef and those of Mr Flay been conjured away and away down that dark corridor leaving only their four eyes suspended in mid-air outside the Earl's door, then, surely, they must have reddened to the hue of Mars, reddened and smouldered, and at last broken into flame, so intense was their hatred – broken into flame and circled about one another in ever-narrowing gyres and in swifter and yet swifter flight until, merged into one sizzling globe of ire they must surely have fled, the four in one, leaving a trail of blood behind them in the cold grey air of the corridor, until, screaming as they fly beneath innumerable arches and down the endless passageways of Gormenghast, they found their eyeless bodies once again, and re-entrenched themselves in startled sockets.’  (Early One Morning, p. 365)

Gormenghast
‘Had he thought himself awake he must surely have pursued, however faint his hope of overtaking the slender creature.’  (§19, p. 127)

‘Had his exile in the woods not inured him to loneliness, then he must surely have found these long days insupportable.’  (§45, p. 292)

‘For Titus to have seen a tenth of it must have taken the edge, not off his wonder or speculation, but off the shock of pleasure that he was finally to receive when evening came.’  (§50.i, pp. 312f.)

‘Had she as a girl been naturally joyous yet all that had befallen her must surely have driven away the bright birds, one by one, from her breast.’  (§75, p. 445)

Titus Alone
‘This gun-boom had come just in time, for had it been delayed a moment longer Titus must surely have been grabbed and questioned.’  (§20, p. 35)

‘Some, in his place, must surely have seen battle or the great jaws of carnivores or landscapes of infinite mystery and invention complete with bridges and deep chasms, forests and craters.’  (§49, p. 113)

‘Had it not been that he took up the rearguard station his facial fatuities must surely have maddened his two companions.’  (§78, p. 180)

This list may not be comprehensive, but it'll do.  In each case I find that must jars, and my ear cries out for would instead.  I don't think that this is merely a matter of stylistic preference, but I can't be sure, so I would be interested to hear of similar examples from elsewhere.