Visual summary of operating lessons from John Carmack.

John Carmack built the graphics engines for Doom and Quake, solving the technical problems that made 3D gaming and online multiplayer possible. He approaches software with a brute-force pragmatism, preferring raw performance to elegant abstractions. This collection pulls from his talks and writing to show how he thinks about code, work, and artificial intelligence.

Part 1: Programming & Architecture

  1. On Simplicity: "Sometimes, the elegant implementation is just a function. Not a method. Not a class. Not a framework. Just a function." — Source: [Twitter]
  2. On Feature Cost: "The cost of adding a feature isn't just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion." — Source: [Software Quotes]
  3. On Code Lifespan: "Something that many people don't really appreciate till they've been at it for a long time is that it's not the writing of the program initially, it's the whole lifespan of the program." — Source: [Lex Fridman Podcast]
  4. On State and Flaws: "A large fraction of the flaws in software development are due to programmers not fully understanding all the possible states their code may execute in." — Source: [Twitter]
  5. On Constraints: "If you're willing to restrict the flexibility of your approach, you can almost always do something better." — Source: [Reddit]
  6. On Functional Programming: "Programming in a functional style makes the state presented to your code explicit, which makes it much easier to reason about, and, in a completely pure system, makes thread race conditions impossible." — Source: [Twitter]
  7. On User Value: "Everything that we're doing really should flow from user value." — Source: [Lex Fridman Podcast]
  8. On Low-Level Code: "Low-level programming is good for the programmer's soul." — Source: [Software Quotes]
  9. On Tooling: "Anything that can be syntactically allowed in your language... is going to show up eventually in a large enough codebase. Good intentions aren’t going to keep it from happening. You need automated tools and guardrails." — Source: [Lex Fridman Podcast]
  10. On Half-Life of Code: "Code should be re-examined every two years. Technology and your own understanding change so rapidly that code older than two years is likely a liability or suboptimal." — Source: [Joe Rogan Experience]

Part 2: Optimization & Performance

  1. On Hardware Limits: "More of the world than many might imagine could run on outdated hardware if software optimization was truly a priority." — Source: [Reddit]
  2. On Abstractions: "It is not that uncommon for the cost of an abstraction to outweigh the benefit it delivers. Kill one today!" — Source: [QuoteFancy]
  3. On Premature Optimization: "You can prematurely optimize maintainability, flexibility, security, and robustness just like you can performance." — Source: [Twitter]
  4. On Future-Proofing: "I will never waste time making code more flexible just for the sake of making it flexible. It generally makes code more abstract and difficult to understand, and it's a waste of time if it's never even used." — Source: [Reddit]
  5. On Brute Force: "Sometimes the best approach is just to apply brute force until you hit a wall, then optimize only the parts that are breaking." — Source: [Lex Fridman Podcast]
  6. On Latency: "Latency is the most important part of VR. If you have that offset, your body is no longer immersed. The speed of light sucks." — Source: [Oculus Connect]
  7. On Java: "The biggest problem is that Java is really slow." — Source: [Twitter]
  8. On Craftsmanship: "There’s something so fulfilling about becoming a craftsman of a thing... You want to find the joy in it." — Source: [Lex Fridman Podcast]
  9. On Execution Speed: "Every millisecond counts. Shaving off latency is a war that must be fought at the driver and firmware level." — Source: [Oculus Connect]

Part 3: Problem Solving & Engineering Mindset

  1. On Iteration: "If you aren't sure which way to do something, do it both ways and see which works better." — Source: [AZ Quotes]
  2. On Weaponized Curiosity: "You can deploy your curiosity to find—to kind of like make things useful and valuable to you even if they don't immediately appear that way." — Source: [Y Combinator]
  3. On Breaking Ideas: "I try to break my own ideas as quickly as possible. If an idea survives my own rigorous internal critique, it might be worth pursuing." — Source: [Unwinnable]
  4. On Being in the Mud: "Great ideas don't come from eureka moments in a vacuum but from being down in the mud working on the problems." — Source: [Liam Zebedee]
  5. On Humility: "You have to be open to the fact that everything that you're doing is just littered with flaws. Whatever stream of code you output, there is going to be a statistical regularity of things that you just make mistakes on." — Source: [Lex Fridman Podcast]
  6. On Preparation: "You're going to make more total progress if you say, 'I'm preparing myself with this broad set of tools,' and then looking for opportunities to deploy the tools that you've built." — Source: [Lex Fridman Podcast]
  7. On Software vs. Aerospace: "The work that I do in video games is actually far more complicated than the aerospace work, but the aerospace work, while it may be simple, is not easy." — Source: [Armadillo Aerospace Archive]
  8. On Simplification: "We can sketch out all of our vehicle subsystems essentially on the back of a napkin." — Source: [Armadillo Aerospace Archive]
  9. On Patents: "The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying." — Source: [Slashdot]
  10. On Arrogance: "A certain level of arrogance is necessary for a developer—the confidence to believe you can solve a problem that has stumped everyone else." — Source: [Joe Rogan Experience]

Part 4: Focus & Work Ethic

  1. On Hard Work: "Focused, hard work is the real key to success. Keep your eyes on the goal, and just keep taking the next step towards completing it." — Source: [AEFlash]
  2. On True Focus: "Focus is a matter of deciding what things you're not going to do." — Source: [AZ Quotes]
  3. On Working More: "40 hours a week is kind of a part-time job... If you're doing what you think is important work that you're passionate about, working more gets more done. It's really not possible to argue with that." — Source: [Startup Archive]
  4. On Obsession: "There is a power to obsession and being able to obsess over something—your life's work. Instead of work-life balance, it's your life's work." — Source: [PlayStation Lifestyle]
  5. On Sleep Limits: "Productivity falls off a cliff after 13 hours. I avoid all-nighters because the mushy brain state leads to bugs that take more time to fix than the work was worth." — Source: [Y Combinator]
  6. On Sleep Priority: "I always try to get 8 hours of sleep... you can work 100 hours a week and still get 8 hours of sleep if you prioritize things correctly." — Source: [Reddit]
  7. On Immersion: "I consider myself in the groove only when I begin dreaming about the problem space. Dreaming is the mind's way of synthesizing complex information into a useful form." — Source: [Reddit]
  8. On the Grind: "It's hard work. Embrace the grind with it, and understand as much as you can." — Source: [Lex Fridman Podcast]
  9. On Retreats: "To master a new field, take a solo retreat. Check into a secluded hotel with nothing but a laptop and a stack of reference books, without internet or phone access." — Source: [Reddit]

Part 5: Management, Teams & Process

  1. On Bureaucracy: "We have a ridiculous amount of people and resources, but we constantly self-sabotage and squander effort. I have never been able to kill stupid things before they cause damage, or set a direction and have a team actually stick to it." — Source: [Business Insider]
  2. On Transparency: "Use public text files to log daily progress and technical thoughts. Everyone knows what the lead programmer is working on, creating a self-imposed deadline." — Source: [id Software Plan Files]
  3. On Deadlines: "I no longer think 'It’ll be done when it’s done' is the appropriate way to build games. Time matters... if it’s a year or two late, you need to be making a different game." — Source: [Reddit]
  4. On Non-Programmers: "One of the big lessons of a big project is you don't want people that aren't really programmers programming, you'll suffer for it!" — Source: [Dev.to]
  5. On Educating vs. Motivating: "Is it easier to motivate a learned individual that never does anything, or educate an ignorant individual that actually produces things?" — Source: [QuoteTab]
  6. On Decisions: "Making one brilliant decision and a whole bunch of mediocre ones isn't as good as making a whole bunch of generally smart decisions throughout the whole process." — Source: [QuoteFancy]
  7. On Empathy in Code: "Software is just a tool to help accomplish something for people. Keep your eyes on the delivered value, and don't over-focus on the specifics of the tools." — Source: [Nicolai Arocci]
  8. On Management Detachment: "It was always the most fun for a long time when I was the chief CNC milling guy... Now, the full-time guys do that and a year has gone by without me writing code for the mill. That saddens me." — Source: [Armadillo Aerospace Archive]
  9. On Giving a Damn: "Embrace the grind... You’ve gotta fill your products with 'give a damn.' Not many of our applications are going that extra mile where the really important magic happens." — Source: [Game Developer]

Part 6: Virtual Reality & The Metaverse

  1. On Screen Replacement: "VR is the eventual replacement for all screens—phones, TVs, monitors." — Source: [Joe Rogan Experience]
  2. On the Metaverse Trap: "The idea of the metaverse can be a honeypot trap for architecture astronauts... programmers and designers who want to only look at things from the very highest levels while skipping the nuts and bolts details." — Source: [Slashdot]
  3. On Immersion over Graphics: "If the story is compelling enough, we don't need haptics or photo-realism... great stories have always pulled us in, no matter what form the media takes." — Source: [Digital Bodies]
  4. On Friction: "VR must become frictionless to succeed. The time it takes to put on a headset and get into an experience is currently a major barrier." — Source: [Oculus Connect]
  5. On World Creation: "If they allow world creation that is actually good looking using just natural language prompting, I think that would be the killer app for VR." — Source: [Reddit]
  6. On Building the Metaverse: "I have pretty good reasons to believe that setting out to build the metaverse is not actually the best way to wind up with the metaverse." — Source: [Slashdot]
  7. On Execution Over Vision: "I prefer shipping a good enough product over waiting for a perfect but unachievable vision of the Metaverse." — Source: [Business Insider]
  8. On Mobile VR: "Mobile is the future of VR. The friction of tethered PC setups will ultimately hold the medium back from mainstream adoption." — Source: [Oculus Connect]
  9. On Hardware Design: "Hardware development is a game of ruthless compromises. You can never have the weight, resolution, and battery life you want all at once." — Source: [Meta Connect]

Part 7: Artificial General Intelligence

  1. On AGI Complexity: "I am not a madman for saying that it is likely that the code for artificial general intelligence is going to be tens of thousands of lines of code—not millions of lines of code." — Source: [Keen Technologies]
  2. On Key Insights: "There’s probably a handful of things—my bet is there’s less than six key insights—that need to be made. Each one of them can probably be written on the back of an envelope." — Source: [Lex Fridman Podcast]
  3. On Interpolation: "Everything is an interpolation problem if you have enough data." — Source: [Twitter]
  4. On Embodiment: "I think that anybody that is all in on the embodied aspect of it, they are tying a huge weight to their ankles... AGI does not need physical embodiment." — Source: [Huberman Lab]
  5. On Human vs. Animal Intelligence: "I think animal intelligence is closer to human intelligence than a lot of people like to think." — Source: [Lex Fridman Podcast]
  6. On Leverage: "Artificial general intelligence seems to me like the highest-leverage moment for a single individual potentially in the history of the world." — Source: [Keen Technologies]
  7. On Universal Remote Workers: "If 10 years from now, we have universal remote employees that are artificial general intelligences, run on clouds... that’s the most prosaic, mundane, most banal use of something like this." — Source: [YouTube]
  8. On Timeline: "I think there is a 50% chance that somewhere there will be signs of life of AGI in 2030, and I’ve probably increased that slightly to 55-60% now." — Source: [YouTube]
  9. On Physics Simulation in AGI: "I view the human brain as a physical system that can be simulated. It's a materialist view; intelligence is substrate independent." — Source: [Joe Rogan Experience]

Part 8: Philosophy, Life & The Future

  1. On Meaning: "The meaning of life is following locally wherever the gradient descent takes you; little tiny steps, local information, winds up leading to all the best answers." — Source: [YouTube]
  2. On Evolution: "We are biological creatures that happenstance of evolution... we have innate drives that evolution crafted for survival. I don't find a lot of value in trying to go much deeper than that." — Source: [Lex Fridman Podcast]
  3. On Barriers to Entry: "In the information age, the barriers to entry just aren't there. The barriers are self-imposed... You need enough pizza and Diet Coke to stick in your refrigerator, a cheap PC, and the dedication to go through with it." — Source: [AZ Quotes]
  4. On Sharing Knowledge: "Programming is not a zero-sum game. Teaching something to a fellow programmer doesn't take it away from you. I'm happy to share what I can, because I'm in it for the love of programming." — Source: [Goodreads]
  5. On Job Automation: "Don’t use power tools because they take people’s jobs is not a winning strategy." — Source: [Simon Willison]
  6. On Democratization: "AI tools will allow the best to reach even greater heights, while enabling smaller teams to accomplish more, and bring in some completely new creator demographics." — Source: [Simon Willison]
  7. On Irrelevant Work: "Software progress has made hand-assembling machine code as irrelevant as chariot wheel maintenance." — Source: [Simon Willison]
  8. On Optimism: "I remain easily optimistic in the face of everything happening. Consider the most amazing person you personally know... Odds are that there are literally millions of their caliber in the world, which is plenty to build a bright future." — Source: [Goodreads]
  9. On Passion Projects: "The world is a museum of passion projects. You may be the pioneer with all the arrows in your back, but if you really want to change something and make something important happen, then you need to go do it." — Source: [Piszek]
  10. On The Roller Coaster: "Think of what we, and others, are doing as building the largest roller coaster in the world." — Source: [Unwinnable]