WRITING AUTHORITY IN LATE MEDIEVAL ... - Cornell University

his daily surveying practices and would have found Trevisa’s explanation if not out-right wrong,
at least far from a useful pedagogical way of explaining with which he came in daily contact. 401
If Trevisa meant to appropriate a Latinate tradition of pedagogy implicitly for the benefits
of his audience, why would he go out of his way to teach a concept in an erroneous way? Why
would he risk being discredited as a man of knowledge and authority by his target audience by
introducing something which was counter-intuitive to their understanding of mathematics?
Further, if this lengthy aside revealed his own limits as a scholar, why would he invest so much
work in it? Why define an equal sided figure labeled with four “costa” and a “dyameter” and
then claim that there is no way to establish their proportional length?
After all, a reader can see four equal sides, so why would it prove difficult to think that if
these be “imeete” ‘measured,’ he could arrive at the measure of a diagonal through proportions?
One explanation is that Trevisa’s glosses do not really attempt to define concepts accurately but
merely mean to highlight the subject matter which they surround. In Somerset’s words,
Two of these annotations are as purely informational as any of those in De Proprietatibus rerum:
on 143v Trevisa explains the meaning of ‘dyameter’ and ‘costa’ (that is, side) with the aid of a
diagram, while on 144v he explains the meaning of ‘speculabilia’ and contrasts it with ‘agibilia.’
But there is more to these two glosses than that. They appear in the midst of Giles’s exposition on
‘consaile,’ the second of four powers involved in ruling a city, and are themselves counsel for
counselors: they explain (even if Trevisa does get it slightly wrong) two topics on which it is
neither advisable nor necessary for a ‘consaile’ to offer ‘consaile’ [My emphasis]. 402
Yet, what would be the purpose of using “slightly wrong” comments to highlight that ‘consaile’
is neither advisable nor necessary when thinking of geometric or scientific ideas? Certainly,
Trevisa’s mathematical mistakes would have called the reader to attention—just as much as the
drawing, the lengthy explanation, and the odd choice for a gloss; however, the argumentative
pay-off—that “consaile” is not geometry or parts of nature—would be minimal since in telling us
what council is not, Trevisa most certainly does not tell us what it actually is.
401 On Berkeley’s experience with surveying, see Hanna “Sir Thomas” 885-886.
402 Somerset 76-77.
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