Body and Soul in Ancient Philosophy

Stoics on souls and demons: Reconstructing Stoic demonology 385
(1) Demons are psychic entities.
(2) Our own embodied rational soul can be described as an internal
demon.
(3) External demons in the strict sense are non-human in origin; they are
separated parts of the divine aetherial pneuma.
(4) There are also human disembodied souls, surviving after death and
roaming through the air as psychic entities. Stricty speaking they
are called hÞroes, but we may perhaps assume that they were considered
to be a subspecies of the genus ‘demons’. Probably these hÞroes
are able to perform the same functions as demons in the proper
sense.
(5) Good external demons or hÞroes are guardians and overseers experiencing
sympatheia with man. They may also play a role in divination.
(6) There are also bad external demons, though probably not in the
sense of punishing spirits working for god. We may assume, although
positive evidence is lacking, that they have not been created
bad, but that their badness, as in the case of humans, is due to their
own choice, accompanied by a relaxation of their pneumatic tonos.
The early Stoic demonology constituted by these tenets was integrated
into the general framework of Stoic physics in various ways. Anti-Epicurean
arguments concerning the cohesive force of the soul allegedly
supported the possibility of separately existing souls. External nonhuman
demons could then be regarded in an analogous way, as apospasmata
of the aetherial pneuma. They were thought to be kept alive, quite
like the divine heavenly bodies, by exhalations. Moreover, questions
concerning the survival or non-survival of individual souls and concerning
the good or bad character of demons could be connected to the
theory of increasing and decreasing psychic tension (tonos). Such connections
to the basic framework of Stoic physics suggest that Stoic demonology
should not be seen as supernatural intrusion of traditional religion
in an otherwise naturalistic cosmo-theology: the early Stoics in
their own way tried to come up with a rational and ‘physicalized’ demonology.
Accordingly, if we want to look for an early modern parallel,
it is not the radical Spinoza we should turn to, but rather the many seventeenth
century philosophers who tried to integrate the allegedly ‘preternatural
phenomena’ of traditional demonology into their physical or
metaphysical systems of causation. 71
71 Robert Boyle, for example, spoke of three categories of things: things “super-