3. Neo-Platonism. By the third century A.D. a fusion
of Platonic and Aristotelian doctrines had been formu-
lated (also in Greek) by Plotinus, an Alexandrian phi-
losopher teaching in Rome. He accepted the doctrine
that the Platonic ideas formed a world of their own,
that they were universals rather than particulars, and
that they were more real than the particulars for which
they were the models. But he added certain details
which lingered on and which can be found as late as
the end of the eighteenth century, at least in England.
These details, which are neither in Plato nor in Aris-
totle, were foreshadowed in the works of Philo Judaeus
(who was active in the early part of the first Christian
century) and in those of Numenius, a second-century
figure, and probably in others now forgotten. Plotinus'
innovations in the history of the meanings of idea may
be summarized as follows.
(1) The world of ideas in Plotinus forms a hierarchy
at the apex of which were the most real, most general,
best, and most beautiful and at the base of which were
the least real, most particular (individual), worst, and
ugliest. At the very top of the hierarchy is that Idea
which is so general that it can only be called The One.
Immediately below it—or him—is the Intelligence
(Nous) and the Soul of the World. The Intelligence
gives rise to another scale of beings, the Ideas. The
Soul of the World is the source of all the other souls,
of men, beasts, and plants. Reality thus becomes some-
thing which has degrees, matter being the least real
and hence the most evil and the ugliest. It is the com-
plete absence of reality.
(2) By a process called emanation the beings on the
lower levels flow out of those above them like, to use
Plotinus' own metaphor, light from a candle which
disappears finally into darkness. The process of emana-
tion has no source in either Plato or Aristotle; it is
distinctive of Neo-Platonism. It comes to a terminus
in the darkness of the material world, at which level
beings strive to move upward and gain the greater
reality from which they descended. They strive, in
short, to realize the potentialities that are in them. Men
do this by turning away from the bodily life, practicing
asceticism so as to deny their animal and vegetable
nature, engaging in the contemplation of ideas, and
finally merging into the One in a mystic vision. The
process of emanation follows the pattern of a logical
hierarchy, exemplified in biology when varieties are
collected into species, species into genera, genera into
families, families into orders, orders into classes, classes
into phyla, and phyla into kingdoms.
Plotinus' pupil Porphyry bequeathed to posterity a
logical hierarchy which became standard in the teach-
ing of philosophy to beginners. It is called the Tree
of Porphyry.
The classes were subdivided by a technique known as
dichotomy, but neither Porphyry nor anyone else ever
explained where one was to cut a class in two. When
ascending the scale one drops off those characteristics
which differentiate and thus one becomes absorbed into
a more inclusive but simpler class. That is, there are
more sensible beings than rational animals but the
latter group has more traits than the former.
(3) The ideas in Plotinus are known by a special
process sometimes called “intellectual intuition.” They
are not expandible into declarative sentences but are
apprehended as visual objects are apprehended, as
units. Plotinus thought—wrongly—that the Egyptian
hieroglyphs were perceptual presentations of ideas;
later, in the Italian Renaissance, much was made of
this. In fact it was the hint that in all probability
developed into that great mass of writings and draw-
ings known as emblem literature.
(4) The ideas apparently could be presented to the
mind of an individual without the stimulation of an
object. Plotinus held that an artist desiring to make
a statue of Zeus beheld in a sort of vision the idea
of the god and put that into stone. Beauty was in fact
the visual presence of the ideal or form and since the
soul was the Aristotelian form of the body, the two
forms responded sympathetically to each other. This
application of the theory of ideas also became impor-
tant in the Renaissance and later, and the doctrine that
painters should paint the ideal rather than the physical
lasted through Ingres into the nineteenth century.