Know what you can - and can't - control!
Stoics did not sit idly by and complain about the future. They would
Act in good faith - while acknowledging that fate can intervene to disrupt the outcome.
Accept the outcome, as their intentions were just, and they did their best to affect a favourable outcome.
One of the most important themes in Stoic literature: know what you can control and know what is beyond your control.
You control your thoughts, goals, and values...basically, the things inside your head and the actions you take. Conduct yourself with honour and always do your best. Setting the appropriate goal and doing your best to achieve it will help you attain happiness and tranquility (a deliberated calm that comes from the absence of negative emotions).
Worrying about things over which we have no control is pointless - an exercise in futility. It will only lead you to distress and lead you away from tranquility.
Use reason to identify those events where you have no control, versus events where you have partial control. Remember, your actions may influence the outcome of an event, but not control it. Know the difference and adjust your goals accordingly. Be confident and take comfort in "doing your best" to affect the outcome of an event.
Modern scholars of the literature (William B. Irvine and others) suggest that the stoics were fatalistic with respect to the past and present, as you can't change the past and the present is fleeting. Their reasoning works well within the parameters of attaining tranquility - an absence of negative emotions.
Accept the past for what it is. Fretting about the past won't bring you peace.
Embrace the present. Wishing it were different prevents you from enjoying what life has to offer now.
Setting the appropriate goal
To illustrate this point, the ancients used the story of an archer letting loose his arrow.
Let's take that example and imagine an athlete competing in an archery event. The archer has control over everything up to the release of the arrow: her training, preparation, skill level, and quality and maintenance of the bow and arrow.
Once the arrow has been released, events outside of her control will determine whether or not she will hit the target: has the wind changed, the target moved, or have obstacles intervened.
To achieve her goal, the stoic needs to acknowledge that the outcome will be influenced, but not controlled by her action. She needs to set the appropriate goal: to do her best to hit the target. With this goal set, she is guaranteed of success - whether or not she hits the target. She can find satisfaction in knowing that she competed to the best of her ability.
If she sets the wrong goal - to win the competition - she will be disappointed if the fates conspire against her, or she is simply bested by a better competitor.
Set the right goal and celebrate the fact that you have done your best...then learn from the experience. You can be just as happy with a bronze medal, or no medal at all, if you have done your best. Most importantly, teach your children to do their best and celebrate in that.
A real world example
Who hasn't applied for a great job? We get excited at the prospect of getting that dream job. After all, we are the best fit...surely they'll see that. We do our best to research the company, send in a meticulous resume, and prepare for an interview. And then we wait. Time passes and our enthusiasm wanes. We don't hear back from them and sadness sets in.
What is in your control?
To do your best when researching the company, crafting your resume and preparing for the interview.
What is not in your control?
The decision being made by the company. Your actions will influence the outcome, but not control the outcome. You may not be the best candidate. You may not have all the qualifications. You may not be the best fit with the corporate culture.
What should your goal be?
To send in the best resume you can and be fully prepared for an interview. Celebrate this...and move on...always doing your best. Or, if fate permits, celebrate getting the job.
God, give me the serenity to accept the things I cannot change,
The courage to change things I can,
And the wisdom to know the difference.
From "The Serenity Prayer" by Reinhold Neibuhr