But suppose that we allow the term 'thirst' or 'desire' to be modified, and say an 'angry thirst,' or a 'revengeful desire,' then the two spheres of desire and anger overlap and become confused.

This case therefore has to be excluded.

And still there remains an exception to the rule in the use of the term 'good,' which is always implied in the object of desire.

These are the discussions of an age before logic; and any one who is wearied by them should remember that they are necessary to the clearing up of ideas in the first development of the human faculties.
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), which may be variously described under the terms righteous indignation, spirit, passion.