Pindar relates thumos to the achievement of excellence (arete). 111 In Ol. 8.4--7 he says that people consult Zeus at Olympia to see if he has any message about human beings striving to take great excellence with thumos, and space to breathe after labours. In the realm of athletic achievement thumos is involved. Elsewhere Pindar describes the sons of Aeacus as those 'willing to cherish a thumos familiar with contest' (Nem. 7.10). This thumos, pursuing excellence, will clearly display courage. Pindar describes the athlete Melissus as 'similar in thumos to the daring of loud-thundering lions' (Is. 4.46). 112 Bacchylides says that Theseus, when challenged, had a 'thumos that did not bend back' (17.82). In Nem. 11.32 Pindar presents a contrast to this courageous kind of thumos that allows admirable behaviour. If someone has an 'unadventuresome thumos', it 'draws him back by the hand and deprives him of honours rightly his'. Heredity may give a person a rightful claim to high achievement but if thumos lack daring, it will discourage risk and prevent accomplishment.
— Shirley Darcus Sullivan
Pindar's athletes are not striving toward excellence as an idea — they are striving from within thumos, from a organ of the soul that can be lion-daring or that can reach back and pull the hand away. This is the pre-Platonic interior: not a unified self choosing, but a field of tendencies, some of which balk at the very thing they want. The "unadventuresome thumos" does not simply refuse; it actively deprives. It draws the man back from honors that are already, by right of blood and training, his. The soul can be its own obstacle without any external antagonist.
What gets quietly lost when we read this through a modern lens is the non-moral quality of thumos here. The lion-daring Melissus does not have a better character than the one who shrinks — he has a different soul-weather. Heredity can establish a claim; thumos either makes good on it or it doesn't. There is no program for converting a balk into a charge. Pindar names the condition; he does not prescribe a path through it. That honesty — the acknowledgment that the soul's daring is given, not constructed — is precisely what later psychologies, trained on the grammar of self-improvement, find hardest to sit with.
Shirley Darcus Sullivan·Psychological and Ethical Ideas What Early Greeks Say·1995