Handbook of the History of Logic: - Fordham University Faculty

The Latin Tradition of Logic to 1100 29
reach after learning (and, presumably, justice), and this is what is meant when we
speak of people being more or less learned or just.
Logic in Eriugena’s ‘Periphyseon’: the project and its sources
It is not in the glosses to Martianus’s logical treatise, but in his long and ambitious
theological dialogue, the Periphyseon (c. 862-6) [John Scottus Eriugena,
1996-2003] where Eriugena develops his views on logic most thoroughly. The Periphyseon
treats of universal nature in its four different forms: as uncreated and
creating (God) — Book I; as created and creating (the Primordial Forms, which
are similar to the Platonic world of Ideas) — Book II; created and not-creating
(the sensible world) — Book III; uncreated and uncreating (God, as that to which
all things return) — Books IV and V). Eriugena’s main way of articulating the
distinction between God and his creation in Book I is through an extended examination
of whether God fits any of the ten Categories. The theme is Augustinian,
and Alcuin had highlighted it (above, 2.1). Eriugena, however, will give a sharply
different answer from Augustine: even with regard to the first of the Categories —
substance or, as Eriugena, following the Ten Categories calls it, ousia — it is truer
to deny it of God than attribute it to him. But the innovativeness of Eriugena’s
presentation goes far beyond this daring theology: he has unusual ideas about the
inter-relation of the Categories, universals, particulars and the nature of ousia,
and the relationship between bodies and the system of Categories. But, before
considering these themes, it is worth considering what Eriugena’s sources might
have been: although his method differed radically from the paraphrasing, cutting
and pasting of Alcuin, his ideas had some definite starting-points.
The number of logical works Eriugena can be shown definitely to have used,
from explicit references or definite parallels, is not large. He uses the Ten Categories
extensively, but there is no sign that he knew Aristotle’s Categories itself
or Boethius’s commentary to it. He was also, understandably, influenced by Martianus,
which he had taught, and which sometimes leaves its traces on his phrasing.
Although scholars, rightly, have seen Porphyry’s Tree of genera and species,
interpreted in a highly realistic fashion, as a guiding principle of his thought,
there is scant evidence that Eriugena knew the text itself or either of Boethius’s
commentaries, rather than having gathered Porphyry’s main ideas through the
encyclopaedic accounts. One passage in Book III (702D-3B — references are to
the columns of the edition in Patrologia Latina 122, since they are preserved in
the later editions and translations) on substantial species has some loose parallels
with Boethius’s second Isagoge commentary [Boethius, 1906, 200], but nothing
close enough to make borrowing even a probability. (On Eriugena’s knowledge,
indirect and possibly direct, of the Isagoge, see [Erismann, 2004, 405-12].) Eriugena
has one, very passing reference to Aristotle’s On Interpretation, inBookII
(597C), where he refers readers to it in order to find out about possibility and
impossibility. Although so vague a reference seems second-hand, none of the encyclopaedic
accounts indicate that Aristotle discusses modality in this treatise, and