Post-it note math

It was October 2000 or thereabouts and Jacob Lund Fisker wanted to know if someone could live a sustainable and rich life.

“I did a little back of the envelope math. We physicist restrict ourselves to post it notes typically. I took the global GDP, divided it by the global population, and took our ecological footprint number and divided by it as well. If everyone did what I was setting out to do, the maximum each person could spend was six thousand dollars per person per year.” – Jacob Lund Fisker, Through Conversations, November 2021

He did it and Fisker retired early.

There’s a few things going on with FIRE. One is attention grabbing, everyone has a means to share their story and the atypical gets attention. Another is the financial conditions, it’s easier (though not easy) than ever to make a large amount of money, in a short amount of time, and invest in a mostly up market. The last and staying part of FIRE is the intentionality. It is impossible to FIRE without prioritizing one’s life.

Fisker’s philosophy is my favorite because he’s a system thinker. Early Retirement Extreme is a book that starts with systems and ends with personal finance. Saving half of one’s income is the act but you can’t do just one thing.

We’ve looked at spreadsheets for emergency funds, 401Ks, and how many touchdowns a quarterback will throw. Spreadsheets offer precision with numbers but don’t address our systems. Basic math is fine if the system is great but it doesn’t matter how great the math if the system is shit.

My two favorite books about systems are Fisker’s book Early Retirement Extreme and The Systems Bible.