Are we born this way? Aristotle thought we could learn habits, but his student Theophrastus believed our internal dynamics are constant. The debate ranges on, now operationalized in diagnostic manuals for personality disorders. No one is better than Horwitz at quickly laying out the debate, the limits of personality disorders, and the stalled development of the DSM-5 dimensional model. Over here, we’re Team Aristotle: no one is born virtuous, but can cultivate habits which alter character. Character is situated in circumstances of birth, wealth, and power, etc., ad infinitum. You learn to be this way.