The psychology of Plato extends no further than the division of the soul
into the rational, irascible, and concupiscent elements, which, as far as
we know, was first made by him, and has been retained by Aristotle and
succeeding ethical writers. The chief difficulty in this early analysis of
the mind is to define exactly the place of the irascible faculty ([Greek:
thumo/s]), which may be variously described under the terms righteous
indignation, spirit, passion. It is the foundation of courage, which
includes in Plato {lxviii} moral courage, the courage of enduring pain,
and of surmounting intellectual difficulties, as well as of meeting
dangers in war. Though irrational, it inclines to side with the rational:
it cannot be aroused by punishment when justly inflicted: it sometimes
takes the form of an enthusiasm which sustains a man in the performance of
great actions. It is the 'lion heart' with which the reason makes a treaty
(ix. 589 B). On the other hand it is negative rather than positive; it is
indignant at wrong or falsehood, but does not, like Love in the Symposium
and Phaedrus, aspire to the vision of Truth or Good. It is the peremptory
military spirit which prevails in the government of honour. It differs
from anger ([Greek: o)rgê/]), this latter term having no accessory notion
of righteous indignation. Although Aristotle has retained the word, yet we
may observe that 'passion' ([Greek: thumo/s]) has with him lost its
affinity to the rational and has become indistinguishable from 'anger'
([Greek: o)rgê/]). And to this vernacular use Plato himself in the Laws
seems to revert (ix. 836 B), though not always (v. 731 A). By modern
philosophy too, as well as in our ordinary conversation, the words anger
or passion are employed almost exclusively in a bad sense; there is no
connotation of a just or reasonable cause by which they are aroused. The
feeling of 'righteous indignation' is too partial and accidental to admit
of our regarding it as a separate virtue or habit. We are tempted also to
doubt whether Plato is right in supposing that an offender, however justly
condemned, could be expected to acknowledge the justice of his sentence;
this is the spirit of a philosopher or martyr rather than of a criminal.
We may observe (p. 444 D, E) how nearly Plato approaches Aristotle's
famous thesis, that 'good actions produce good habits.' The words 'as
healthy practices ([Greek: e)pitêdeu/mata]) produce health, so do just
practices produce justice,' have a sound very like the Nicomachean Ethics.
But we note also that an incidental remark in Plato has become a
far-reaching principle in Aristotle, and an inseparable part of a great
Ethical system.