Algorithms to Live By: What Computer Science Knows About Your Life That You Don’t
Here’s the pitch of this book in one line: the problems you wrestle with every day β when to stop apartment hunting, what to throw away, how to plan a schedule that keeps falling apart β are problems computer scientists solved decades ago. Not for humans. For machines. But the maths doesn’t care which one is asking. Brian Christian, working with cognitive scientist Tom Griffiths, went looking for the overlap between computer science and human life, and found it’s much bigger than anyone expected. Sorting algorithms explain how to organise your kitchen. Caching explains what to keep on your desk. A problem called “optimal stopping” explains dating, hiring, and house hunting all at once. This isn’t a productivity book dressed up in science words. It is a translation of actual math into algorithms to live by with practical examples you can apply to decisions you are making this week. Brian Christian, working with cognitive scientist Tom Griffiths, went looking for the overlap between computer science and human life, and found it’s much bigger than anyone expected. Sorting algorithms explain how to organise your kitchen. Caching explains what to keep on your desk. A problem called “optimal stopping” explains dating, hiring, and house hunting all at once. π The 37% Rule: when to stop looking and choose This is the single most quoted idea from the book, and it earns the reputation. The setup, in computer science, is called the “secretary problem”: you’re interviewing candidates one at a time, you must decide to accept or reject each one on the spot, and you can never go back to someone you rejected. How do you maximise your odds of picking the best one? If you want to geek out on the actual math behind it, you can read the original definition on Wikipedia’s Secretary Problem page. The proven answer: spend the first 37% of your search purely looking β reject everyone, no matter how good β then commit to the first candidate afterward who beats everyone you’ve seen so far. That number isn’t a rough guess. It’s the mathematically optimal stopping point. It gives you roughly a 37% chance of landing the actual best option β which sounds unimpressive until you realise that’s the best any strategy can do under those rules. This maps almost perfectly onto real decisions: You’re not trying to guarantee the best outcome. You’re trying to stop losing to indecision. The deeper comfort here: regret over “did I look enough” and regret over “did I settle too fast” are both irrational once you know the math. There’s a correct amount of looking, and it’s less than your anxiety tells you. ποΈWhen Over-Sorting Costs More Than Mess: Algorithms to Live By Practical Examples Computer scientists obsess over sorting because it’s genuinely costly, computationally speaking. And Christian’s insight is that we over-sort our physical lives for the exact same reason it’s expensive for a computer: most of what you sort, you never look for again. Your bookshelf doesn’t need to be alphabetised if you rarely search it by author. Your filing cabinet doesn’t need a perfect system if you retrieve five documents a year from it. The computer science answer to “should I organise this?” isn’t “yes, always.” It’s a real trade-off: Sorting cost vs. searching cost. If you’ll search something constantly, sort it once, thoroughly. If you’ll search it rarely, don’t bother β a quick scan through mess is cheaper than the hours spent maintaining order nobody uses. This alone is permission to stop feeling guilty about the messy drawer. Some mess is computationally correct. If you’re struggling to let go of perfectionism in your home organisation, check out our previous post on [Why Productivity Isn’t About Perfection] (Internal Link Placeholder). π₯ Caching: keep what you touch, drop what you don’t Related idea, and one of the most immediately useful in the whole book. Computers use “caching” β keeping recently and frequently used data somewhere fast to reach, and pushing rarely used data somewhere slower and out of the way. Not because the rare stuff doesn’t matter. Because retrieval speed should match how often you’ll need it. Apply this literally to your physical space: Most people organise by category (all the pens together, all the cables together) instead of by frequency of use. Christian’s point is that frequency should win. A rarely used “important” document can live further away than a daily-used trivial one β access speed should track usage, not sentimental importance. This is also, quietly, the best argument for a capsule wardrobe you’ll ever read in a computer science book: the clothes you actually wear belong in the fastest-access spot. Everything else is cache eviction waiting to happen. βοΈ Explore vs. Exploit: the tension behind every choice This is the idea I think about the most, months after reading it. Every time you choose, you’re balancing two competing instincts: Computer science has a precise answer for when to favour which, and it comes down to one variable: how much time do you have left? To understand why this balance is crucial for long-term happiness, we recommend reading The Psychology of Money: A Masterclass in Perspective. Early on β lots of time horizon remaining β exploration wins. Try the new restaurant. Take the unfamiliar project. The potential upside of discovering something great has a long runway to pay off. Later β less time horizon remaining β exploitation wins. Go back to what you know is good. There’s less time left to benefit from a discovery, so the sure thing becomes more valuable than the gamble. This explains something that used to look like a personality flaw and is actually optimal behaviour: why older people order the same dish at the same restaurant, and why younger people are more willing to try the weird new place. It’s not closed-mindedness. It’s correct math for a shorter remaining horizon. It also reframes career and life decisions. A season of trying many things isn’t indecision β it’s the right strategy for


