Tim Ferriss is a New York Times bestselling author multiple times over, an early stage investor in the likes of Uber, Facebook and Twitter and the host of his namesake podcast, which has been downloaded more than 150 million times. He also suffers from bipolar depression, he says in a recently released TED Talk, "Tim Ferriss: Why you should define your fears instead of your goals." "I've learned a lot," from dealing with bipolar depression, says Ferriss. "I've had a lot of at-bats, many rounds in the ring with darkness." Some of what he's learned on this personal journey has helped him professionally as well. "The tool I've found which has proven to be the most reliable safety net for emotional free fall is actually the same tool that has helped me to make my best business decisions," he says. "And it is ... Stoicism."

Stoicism is an ancient Greco-Roman philosophy about recognizing what you can and cannot control, in order to focus your energy exclusively on that which you can. "This decreases emotional reactivity, which can be a superpower," says Ferriss. "[L]et's say you're a quarterback. You miss a pass. You get furious with yourself. That could cost you a game. If you're a CEO, and you fly off the handle at a very valued employee because of a minor infraction, that could cost you the employee," he explains. Ferriss first learned about Stoicism during a particularly trying time in 2004. A good friend of his died unexpectedly, the girlfriend he had thought he would marry left him and he was working at an unsustainable pace. He was struggling.

"At the time, I was working on my first real business. I had no idea what I was doing," says Ferriss. "I was working 14-plus hour days, seven days a week. I was using stimulants to get going. I was using depressants to wind down and go to sleep. It was a disaster. I felt completely trapped." Desperate for solutions, Ferriss came upon a quote by Seneca the Younger, a famous Stoic writer: "We suffer more often in imagination than in reality." Intrigued, Ferriss read more of his work and came to learn a tool the anxious Stoic writer used called "premeditatio malorum," which means "the pre-meditation of evils." The idea is to carefully consider the worst case scenario. By becoming familiar with the worst case scenario, you begin to melt the fear holding you back. "My problem was monkey mind — super loud, very incessant. Just thinking my way through problems doesn't work," says Ferriss. "So I created a written exercise that I called 'fear-setting,' like goal-setting, for myself. ... Super simple." Here are the three steps to setting your fears down on paper, what Ferriss calls "fear-setting." 1. What if I ...? Write down whatever you are afraid of. Then, under whatever you are afraid of, write three subcategories: "Define," where you describe the 10 to 20 worst possible outcomes; "Prevent," where you figure out what you could do to prevent each worst possible outcome from happening; and "Repair," where you decide what is within your power to do to solve the problems that you have presupposed will happen. 2. Write down the potential benefits of trying or even succeeding in some way at whatever goals or tasks you are afraid of. Ferriss recommends this part should to take between 10 to 15 minutes. 3. "The cost of inaction" Write down what may happen if you do not attempt or partially succeed at the goals or tasks you are afraid of. So you should ask yourself: If I avoid this action or decision and actions and decisions like it, what might my life look like in, say, six months, 12 months, three years? says Ferriss. "Any further out, it starts to seem intangible. And really get detailed — again, emotionally, financially, physically, whatever," he says.

The hard choices—what we most fear doing, asking, saying—these are very often exactly what we most need to do. Tim Ferriss bestselling author, tech investor, podcaster

Ferriss goes through the process of documenting his fears and the potential implications of acting or not acting on the tasks or goals several times a year. "And I can trace all of my biggest wins and all of my biggest disasters averted back to doing fear-setting at least once a quarter. It's not a panacea. You'll find that some of your fears are very well-founded," says Ferriss. And in some cases, you may go through the exercise and still be afraid of what you are considering. "But you shouldn't conclude that without first putting them under a microscope," he says.