ichus, the disciple of Porphyry (died
330), transformed Neoplatonism "from a philosophic theorem into a
theological doctrine." The doctrines peculiar to Iamblichus can no
longer be deduced from scientific, but only from practical motives. In
order to justify superstition and the ancient cults, philosophy in
Iamblichus becomes a theurgic, mysteriosophy, spiritualism. Now appears
that series of "Philosophers", in whose case one is frequently unable to
decide whether they are deceivers or deceived, "decepti deceptores," as
Augustine says. A mysterious mysticism of numbers plays a great role.
That which is absurd and mechanical is surrounded with the halo of the
sacramental; myths are proved by pious fancies and pietistic
considerations with a spiritual sound; miracles, even the most foolish,
are believed in and are performed. The philosopher becomes the priest of
magic, and philosophy an instrument of magic. At the same time, the
number of Divine Beings is infinitely increased by the further action of
unlimited speculation. But this fantastic addition which Iamblichus
makes to the inhabitants of Olympus, is the very fact which proves that
Greek philosophy has here returned to mythology, and that the religion
of nature was still a power. And yet no one can deny that, in the fourth
century, even the noblest and choicest minds were found among the
Neoplatonists. So great was the declension, that this Neoplatonic
philosophy was still the protecting roof for many influential and
earnest thinkers, although swindlers and hypocrites also concealed
themselves under this roof. In relation to some points of doctrine, at
any rate, the dogmatic of Iamblichus marks an advance. Thus, the
emphasis he lays on the idea that evil has its seat in the will, is an
important fact; and in general the significance he assigns to the will
is perhaps the most important advance in psychology, and one which could
not fail to have great influence on dogmatic also (Augustine). It
likewise deserves to be noted that Iamblichus disputed Plotinus'
doctrine of the divinity of the human soul.

The numerous disciples of Iamblichus (Aedesius, Chrysantius, Eusebius,
Priscus, Sopater, Sallust and especially Maximus, the most celebrated)
did little to further speculation; they occupied themselves partly with
commenting on the writings of the earlier philosophers (particularly
Themistius), partly as missionaries of their mysticism. The interests
and aims of these ph