pathē

The Stoic theory of emotion is more precise than the modern English word passion suggests. The four primary pathē, all caused by mistaken assent to impressions:

• Epithumia (appetite, desire) — directed at a present or future indifferent misidentified as a good. The greedy reaching for money, the lustful reaching for sex, the ambitious reaching for status.
• Hēdonē (pleasure) — taken in a present indifferent misidentified as a good. The satisfaction at receiving praise, the delight at a luxury, the pleasure of revenge.
• Phobos (fear) — directed at a future indifferent misidentified as an evil. The fear of death, of illness, of disgrace, of poverty.
• Lupē (distress, grief) — at a present indifferent misidentified as an evil. The pain at having lost a job, the grief at a death, the upset at criticism.

Each maps to the time and value-quadrant: present-good, present-evil, future-good, future-evil. Together they exhaust the basic logical space of disordered emotional response. The Stoic claim is that all psychological disturbance reduces to one of these four — and all of them stem from a category error: treating indifferents (things that are not in our power and not actually good or bad in themselves) as if they were genuinely good or genuinely evil.

This is why Stoic practice puts so much weight on the moment of sunkatathesis (assent). The mistaken category-judgment is the root cause — the misclassification of an adiaphoron as a genuine good or evil. Catch the impression before assent is granted; refuse the bad classification; the passion does not arise.

A subtle point. The Stoics did not deny that humans experience these states. They denied that the experience was appropriate — they were errors, in the technical sense, and the project of philosophy was their gradual elimination. The eupatheiai (good feelings) are what is left in the sage when the pathē have been replaced by accurate judgments.