Self Discipline: How to Build Mental Toughness and Focus to Achieve Your Goals (How to Develop Spartan Discipline, Unbreakable Mental Toughness, and Relentless Willpower)

And we have an animal element: the part of us that's moved by instinct, impulse, and emotion—which we share with the animals. This is the part of us that succumbs to instant gratification and indiscipline.

To be self-disciplined, the stoics tell us, means to make the god within—not the animal within—the master of...