Epictetus, a renowned Stoic philosopher in ancient time, has provided us some insights on how to live a happy and calm life. In order to achieve ataraxia – an ancient greek word for serenity – one should master the dichotomy of control.
On the one hand, there are things in our lives over which we have (complete) control. On the other hand, there are things that are not completely under our control. The dichotomy of control teaches us to focus our time, energy and resources on the former and lean how to make peace with the latter.
However, modern Stoics such as Gregory Lopez and Massimo Pigliucci, rethinks the dichotomy of control by proposing a third category: things we can influence but cannot completely control. This is the theme for the week 2 exercise on their workbook on Stoicism, Live Like A Stoic: 52 Exercises for Cultivating Good Life.
For example, we may want to get promoted, but being actually promoted is not under our control. However, by working hard, we might get actually be promoted. This part is under control (working hard) which may influence the desired outcome (getting the outcome).
On Being Stoic 