“It is hard to battle with one’s own anger, for whatever it wants it buys at the price of the soul.” (S 85)
Heraclitus formulates an early expression of the truism that one can be consumed by anger. It can lead one to act unwisely, to compromise what is in the greatest interest of the community or in one’s own self interest.
The main question regarding the interpretation of this passage is the correct translation of thymos. Kahn and Robinson, among others, translate the term as “passion,” but then go on to explain that this is likely not best identified with sexual passion but with “anger” or “rage.” Plutarch, Plato, and Aristotle understood the term in this way, contrasting the term with epithymia, sexual appetite (see Kahn, p. 242 ff).
Heraclitus does not appear to think that one should quell all emotion, that we should extinguish it, and with that buy tranquility. He does think some may have a duty to serve and even die in war, and would be honored for that (K 100 [D24]). Yet the use of force for which one would be honored would be at the service of law. As Heraclitus notes in Fragment 30 (D 44), “the people must fight for the law as for their city wall.” But this is not something done with uncontrolled rage.
Rage in fact is a sign of not having self control. In Fragment 60 (D 87), Heraclitus speaks of the fool, who gets worked up on any views he may hear. He also speaks of the many worthless who take the mob as their teacher. Wisdom by contrast requires knowing “the plan that steers all things” (F 54 [D 41]). It requires battling one’s rage and knowing perhaps how to wisely direct it rather than being directed by it. As Kahn suggests, Democritus’ statement on the need for self-control serves as a sensible compliment to Heraclitus’ fragment: “although it is hard to fight against anger (themos), it is the task of a man to prevail over it, if he has good sense.” (See Kahn, p. 243, Democritus, F 236).