Prof.
Giuseppe Mazzotta of Yale speaks of reading the
Comedia "horizontally," that is, with attention to the interaction between similar moments across the three canticles.
If we look for example at the invocations that the poet employs in the three poems, suggestive differences among them can be noted. Each invocation addresses a distinct source of inspiration, from which other potentially significant differences flow in turn. The poem is telling us something about how it is to be read. The invocations of the three canticles can be found
here.
The shortest invocation, in the
Inferno, addresses the Muses as
alto ingenio - this can mean high genius, but
ingenium was an ancient Latin term for one's own innate character or nature. From there it extended to the idea of natural capacity, talent, or genius, evolving into a rich and complex sense (see, for example,
here and
here.)
Dante moves quickly to address
mente -- a faculty that
scrivesti ciò ch'io vidi -- wrote that which I saw -- hence a form of memory, of notation, faithful to the pilgrim's experience. The poetry of
Inferno will be faithful to what the pilgrim saw and heard -- poetry in the mode of representation, mimesis, but thanks to
alto ingenio, one that will show its
nobilitate.
By contrast, the invocation of
Purgatorio invokes the
sante Muse, who are asked to let poetry, which is dead, rise again (
risurga). This already is more than natural. What's on offer here is not merely recording, but transformative action:
And let here Calliope rise up for a while
and accompany my song with that strain
which smote the ears of the wretched magpies
so that they despaired of pardon.
Calliope, the Muse of Epic, is called upon in particular to rise up
alquanto -- perhaps not just
for a while, but
to an extent, somewhat. Calliope
is needed
to smite the daughters of Pierus, a
"crowd of foolish sisters" who, according to Ovid, were turned to magpies after inanely challenging and losing a competition with the Muses. To accomplish this, it seems, Calliope needs not rise to the highest level of style. That will be sought and needed in
Paradiso.
The tale of the battle of songs, taken from
Metamorphoses 5, stages the competition, and the contrast between the two performances couldn't be more marked. Calliope, singing of the Rape of Persephone, wins. The judges were the nymphs of Helicon; Athena heard the whole story of how the daughters of Pierus were turned into mimicking magpies.
The invocation of Purgatorio enlists the Muses in a struggle. This is poetry with an active purpose in this world, and it means business. Actually, it means unfinished business, as Purgatorio takes place in time, in the realm of human desire, engagement, choice. Unlike Inferno, things on this mountain are not settled by any means, nor are they fixed in stone. All is in motion. The Purgatorio is quite simply a poem of metamorphosis, like that whose tale of the magpies inspired its invocation.
We'll leave the invocation of the Paradiso for a later moment, for it again calls upon a different source, calling forth yet another mode -- other than pure mimesis or performance - to actualize itself.