John Galt is Prometheus who changed his mind. After centuries of being — Prometheus

"I am absolutely destitute of converts, and, for aught that I can see, the millennial Revelation has been made to me for nothing. Prometheus up in Spaceland was bound for bringing down fire for mortals, but I — poor Flatland Prometheus — lie here in prison for bringing down nothing to my countrymen. Yet I exist in the hope that these memoirs, in some manner, I know not how, may find their way to the minds of humanity in Some Dimension, and may stir up a race of rebels who shall refuse to be confined to limited Dimensionality. That is the hope of my brighter moments."

"I must bear What is ordained with patience, being aware Necessity doth front the universe With an invincible gesture."

"Hard I strove To put away my immortality, Till my collected spirits swelld my heart Almost to bursting; but the strife is past. It is a fearful thing to be a god, And, like a god, endure a mortals pain; To be a show for earth and wondering heaven To gaze and shudder at! But I will live, That Jove may know there is a deathless soul Who neer will be his subject. Yes, tis past. The stedfast Fates confess my absolute will,— Their own co-equal."

"Why should the thirst for knowledge be aroused, only to be disappointed and punished? My volition shrinks from the painful task of recalling my humiliation; yet, like a second Prometheus, I will endure this and worse, if by any means I may arouse in the interiors of Plane and Solid Humanity a spirit of rebellion against the Conceit which would limit our Dimensions to Two or Three or any number short of Infinity."

"It is not time Now to disclose that which requires the seal Of strictest secresy; by guarding which I shall escape the misery of these chains."

"The current rampages of territorial-emotional pugnacity sweeping this planet are not just another civilization failing … They are the birth-pangs of a cosmic Prometheus rising out of the long nightmare of domesticated primate history."