AMS Philadelphia 2009 Abstracts - American Musicological Society

56 Friday morning AMS Philadelphia 2009
FROM TREES TO DEGREES: MENSURAL THEORY
AND METAPHYSICAL QUESTIONS OF BEING
Karen Desmond
New York University
Within the last twenty-five years a handful of scholars have emphasized the necessity of
reading the texts of late medieval music theory within the context of learning at the medieval
university. In this paper, I examine how two central metaphysical debates of the late thirteenth
century impacted both the new systematization of mensural notation proposed by the musician
and mathematician Johannes de Muris in his Notitia, and the subsequent attacks on this
new system by Jacobus, author of Speculum musicae. While certain ars nova treatises circulated
as guides to specific technical problems of notation, Muris’s Notitia represents a whole-scale
overhaul of mensural notation, systematizing it within a particular ontological framework. It
is imperative that we have a full understanding of the frameworks within which Muris and
Jacobus were operating, for only then can we hope to appreciate the proposed innovations,
and the reasons for the irreconcilable issues between the two men.
The first metaphysical debate concerned the unity of form within being. The question was
whether there existed a single form within man (Aquinas, Godfrey of Fontaines), or whether
a plurality of forms existed simultaneously within one being (John Duns Scotus). A related
debate looked at how qualities were understood to change: the plurality-of-forms proponents
outlined a theory of change known as the additive theory while the unity-of-form adherents
rejected this additive theory of change, believing that it assumed characteristics of qualities
that were really only predicable of quantities, and proposed an alternative theory known as
the succession-of-forms theory. While the references within the more well-known Book 7 of
Speculum musicae to these debates are somewhat oblique, Jacobus makes specific and detailed
references to them within chapters of Book 1 and Book 4. I analyze these passages within the
context of the quodlibets by Godfrey, Walter Burley’s de intensione et remissione formarum
and the ordinatio of Duns Scotus. This analysis will show Jacobus clearly advocating the
unity-of-form position, and a close reading of the Notitia in this context will show how Muris
developed his new systemization for mensural notation based on the Scotist position (which
was further developed by John Dumbleton) that a plurality of forms may exist within one being,
and that qualities change through addition or subtraction of degrees. For Muris, there is
but one species of tempus, and within this one species there is a plurality of accidental forms,
which are measured along one dimension. There are not different species of times, just greater
and lesser times. The individual notes are individuated by the quantity of their matter, and
whether parts are added or taken away from this individuating quantity of matter. Jacobus,
on the other hand, holds onto the traditional explanation of the mensural system, conceptualized
as a Porphyrian tree (like the arbor of Johannes de Burgundia) of the different species and
sub-species of note values, each being distinct in their name, definition and essence, and each
having an indivisible unity of form.