The One Rule for Life

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Depending on your perspective, Immanuel Kant was either the most boring person on the planet or a productivity hacker’s wet dream. For over 40 years, he woke up every morning at 5:00 AM and wrote for exactly three hours. He would then lecture at the same university for exactly four hours. He followed that up with lunch at the same restaurant each day. Then, in the afternoon, he would go on an extended walk through the same park, on the same route, leaving and returning home at the exact same time. Every day.

Kant spent his entire life in Königsberg, Prussia. I mean that literally. He never left the city. Despite the sea being an hour away, he never saw it.1

Kant was efficiency personified. He was so mechanical in his habits that his neighbors joked they could tune their clocks based on when he left his apartment each day. He would leave for his daily walk at 3:30 PM, have dinner with the same friend every evening, and return home to finish work and go to bed at exactly 10:00 PM.

It’s easy for us to scoff at a guy like this. What a dweeb. Seriously, get a life, dude.

But Kant was one of the most important and influential thinkers in modern history. He did more to steer the world from his single-room apartment in Prussia than most kings and armies ever did before and since.2

Kant’s Legacy

If you’re living in a democratic society that protects individual rights, you have Kant to partially thank for that. He was the first person to ever envision a global governing body that could guarantee peace across much of the world. He described space/time in such a way that it inspired Einstein’s discovery of relativity.3 He came up with the idea that animals could potentially have rights,4 invented the philosophy of aesthetics and beauty, and resolved a 200-year philosophical debate in the span of a couple hundred pages. He reinvented moral philosophy, from top to bottom, overthrowing ideas that had been the basis of western civilization since Aristotle.

Kant was an intellectual badass. If brains had balls, Kant’s would have been made out of steel. His ideas, particularly about ethics, are still discussed and debated in thousands of universities today.

And that’s what I want to talk about: Kant’s moral philosophy, and why it matters.

Now, I know what you’re saying. Really, Mark? Moral philosophy? Who fucking cares, man? Show me shiny sunset inspirational quotes and cat pics.

Well, that, right there, is moral philosophy. Any time you say, “Who cares?” or “What’s the big deal?” you’re essentially questioning the value of something. Is it worth your time and attention? Is it better/worse than something else? These are all questions of value, they all fall under the umbrella of moral philosophy.

Our moral philosophy determines our values—what we care about and what we don’t care about—and our values determine our decisions, actions, and beliefs. Therefore, moral philosophy applies to everything in our lives. Got it? Good.

Moral philosophy: Because if you have to ask, you probably need it.

Kant’s moral philosophy is unique and counterintuitive. Kant believed that for something to be good, it had to be universal—that is, it can’t be “right” to do something in one situation and “wrong” to do it in another. If lying is wrong, it has to be wrong all the time. It has to be wrong when everyone does it. Period. If it isn’t always right or always wrong, then that cannot be a valid ethical principle.

Kant called these universalized ethical principles “categorical imperatives”—rules to live by that are valid in all contexts, in every situation, to every human being.

Well, holy shit, universal laws that dictate all morality for every human being? Sure, want fries with that?

It’s so impossible, it sounds ludicrous. But Kant made a hell of an attempt. In fact, he made a number of attempts at creating categorical imperatives. Some of those attempts were quickly ripped to shreds by other philosophers. But others have actually held up the test of time to some degree.

One of them, in particular, has kind of stuck. And in all of my years reading and studying philosophy, psychology, and other sciences, it’s one of the most powerful statements I’ve ever come across. Its implications reach into every area of each person’s life. In a single sentence, it sums up the bulk of all of our ethical intuitions and assumptions. And in each situation, it points to a clear direction for how we should be acting and why.

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    One Rule to, Err… Rule Them All

    OK, enough foreplay. Here’s Kant’s Rule:5

    Act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means.

    Immanuel Kant

    I know: what the actual fuck?

    OK, let’s back up for a second.

    Kant believed that rationality was sacred. When I say rationality, I don’t mean like sudoku or chess grandmaster rationality. I mean rationality as the fact that we are the only known creatures in the universe that are able to make decisions, weigh options, and consider the moral implications of any and every action.

    Basically: consciousness.

    To Kant, the only thing that distinguishes us from the rest of the universe is our ability to process information and act consciously in the world. And this, to him, is special. Exceedingly special. For all we know, we are the only shot the universe has at intelligent self-organization. Therefore, we need to take it seriously. And, therefore, rationality and protecting conscious choice must be the basis for all of our moral reasoning.

    Kant wrote that “without rationality, the universe would be a waste, in vain, and without purpose.” To Kant’s mind, without intelligence, and the freedom to exercise that intelligence, we might as well just all be a bunch of rocks. Nothing would matter.

    Therefore, Kant believed that all morality is derived from the protection and promotion of rational consciousness in each individual.

    So, how do you do that?

    Well, Kant’s Rule above.

    Let’s restate Kant’s Rule in more modern language to make it more easily digestible:

    If this version of Kant’s Rule makes sense to you, skip the following grey box. If you’re still confused about how a person can be a “means” or an “end” then this box will explain it further.

    Helpful White Box for People Who Are Still Confused by What “Means” and “Ends” Are

    Let’s say I’m hungry and I want a burrito. I get in my car and drive to Chipotle and order my usual double meat monster that makes me oh-so-happy on a weekly basis.

    In this situation, eating the burrito is my “end” goal. It’s ultimately why I’m doing everything else—getting in the car, driving, buying gas, and so on. All of these things I do to get the burrito are the “means”, i.e., the things I must do in order to achieve my “end.”

    If you call a friend to find out how they’re doing, calling them is a means, finding out how they are doing is your end. If you leave a party early so you can wake up early in the morning, leaving the party is the means, and waking up early is your end.

    Means are things that we do conditionally. I don’t want to get in my car and drive. But I want a burrito. Therefore, driving is the means to my burrito end.

    An end is something that is desired for its own sake. It is the defining motivating factor of our decisions and behaviors. If I wanted to eat a burrito only because my wife wanted a burrito and I wanted to make her happy, then the burrito is no longer my end—it is now a means to an even greater end: making my wife happy. And if I only wanted to make my wife happy so I could hopefully get laid tonight, now my wife’s happiness is a means to a greater end of sex.

    Likely that last example made you squirm a bit and think I’m kind of a dirtbag. And that’s exactly what Kant is talking about. His argument—hell, his rule—states that treating any human being as a means to some other end is the basis of all unethical behavior. So treating a burrito as a means to my wife’s end is fine. It’s good to make your spouse happy sometimes! But if I treat my wife as a means to the end of sex, then I am now treating her as a means, and, Kant would argue, that is some shade of wrong.

    (P.S. If you didn’t notice, I was really hungry while writing this.)

    Let’s give Kant’s Rule the common-sense check.

    • Lying is wrong because you are misleading another person’s conscious behavior in order to achieve your own goal. You are therefore treating that person as a means to your own end. Therefore, lying is unethical.
    • Cheating is unethical for a similar reason. You are violating the expectations of other rational and sentient beings for your own personal aims. You are treating the rules and expectations agreed to with others as a means to your own personal end.
    • Violence, same deal: you are treating another person as a means to some greater political or personal end. Bad, reader. Bad!

    Kant’s formulation checks all the boxes that we would expect from a theory of morality. But it also goes way beyond common-sense morality.

    In fact, I will try to argue that Kant’s Rule plausibly extends to pretty much everything that we value as right and good today. Check it out:

    The Moral Implications of Kant’s Rule

    The list below is incomplete. Some of the items Kant explicitly wrote about. Others are extrapolations that I’ve taken from his work and applied to my own values. My hope is that by the end of it, you see the incredible flexibility of this single moral maxim to extend to almost all areas of human life.

    Immanuel Kant - The one rule for life - collage of diverse happy people
    I would say that Kant’s Rule made all these diverse people happy—but Kant doesn’t give a shit about happiness.


    OK, I’m as lazy as the next guy. Full disclosure. And I often feel guilty about it. We all know that fucking off in the short term inevitably harms us in the long term. But for whatever reason, this short-term gain vs long-term loss calculation never seems to inspire or move us. But that’s not why Kant thinks it’s wrong.

    In fact, Kant would say that this is the wrong way to think about laziness. It’s insufficient. Kant believed that we all had a moral imperative to do the best we can at all times. But he didn’t say to do your best because of self-esteem or personal utility or contributing to society or whatever. He went even further than that.

    He argued you should do your best because anything less is to treat ourselves as a means rather than an end. Yes, you can treat yourself as a means as well. When you’re sitting on the couch, refreshing Twitter for the 28th time, you’re treating your mind and your attention as a mere pleasure receptacle. You are not maximizing the potential of your consciousness. In fact, you are using your consciousness as a means to stimulate your emotional ends.

    This is not only bad, Kant would argue, but it’s unethical. You are actively harming yourself.


    Believe it or not, Kant wasn’t a total party pooper. He enjoyed some wine with his lunch. He smoked a pipe (but only at the same time each morning, and only one bowl of tobacco). Kant wasn’t anti-fun. What he was against, though, was pure escapism.

    He wrote that using alcohol or other means of escaping one’s own life was unethical because it requires you to use your rational mind and freedom as a means to some other end—in this case, getting your next high.6 Kant believed in facing one’s problems. He believed that suffering is sometimes warranted and necessary in life.

    We tend to judge the immorality of addiction by the damage it causes to others. But Kant believed that, first, over-indulgence was fundamentally the act of being immoral to oneself. The harm it did to others was merely collateral damage. It was a failure to confront the reality of one’s own mind and own consciousness, and this failure is akin to lying to oneself or cheating oneself out of precious life potential. And to Kant, lying to yourself is just as unethical as lying to others.

    People Pleasing and Seeking Approval

    OK, I know it’s not a good strategy to be kissing people’s asses all the time, but unethical? Really? Isn’t being really nice to people and making them happy an ethical thing to do? Not necessarily.

    Seeking approval and people pleasing forces you to alter your actions and speech to no longer reflect what you actually think or feel. So, right there, you’re already treating yourself as a means rather than an end. BUT, it gets worse.

    Because if you alter your speech or behavior in order to make others like you, then you are also treating them as a means to your end. You are altering and manipulating their perceptions of you in order to garner a pleasant response from them. Kant would undoubtedly argue that that is also unethical. (How dare you tell me my shirt looks good on me, you unethical piece of shit?)

    I’ve written at length about how people pleasing and seeking approval leads to toxic relationships. But again, as usual, Kant takes it even further. Because Kant was fucking hardcore like that.

    Manipulation or Coercion

    Even if you’re not lying, but you’re communicating with an attitude and purpose of gaining something from someone without their full knowledge or explicit consent, then you are being unethical.

    Kant was big on fully-informed consent. He believed it was the only way for there to be healthy interactions between individuals. It was radical for his time, and it’s something that people still struggle to accept today.

    There are two areas in the modern world where I think the consent issue is huge, and Kant would have a lot to say about it.

    The first is obvious: sex and dating.

    Under Kant’s Rule, anything short of explicit, fully-informed (and fully sober) consent, is ethically out of bounds. This is a hot-button issue today, and I personally think people make it far more complicated than it needs to be. It basically means be respectful. People assume this means asking for permission 20 times on a date. It’s not. All you have to do is state how you feel, ask them how they feel, and then respect whatever response comes your way. That’s it. Not complicated.

    Respect was also sacred within Kant’s moral framework because Kant believed that all conscious creatures have a fundamental dignity that must be respected at all times, and by everyone. For Kant, consent was the act of demonstrating respect. Anything that didn’t lead towards consent between two people was, to some degree, disrespectful. I know that makes Kant sound like an angry grandmother, but the implications of the consent issue are far-reaching and wide, touching every human relationship we have.

    The other modern area that is problematic is sales and advertising.

    Pretty much every marketing tactic is built around treating people as a means to some end (making money). In fact, Kant struggled much of his life with the ethical implications of capitalism and wealth inequality. He believed that it was impossible for anyone to amass a fortune without some degree of manipulation or coercion along the way. Therefore he was dubious of the entire system. He wasn’t anti-capitalist per se (communism didn’t exist yet), but the staggering wealth inequality of his time did make him uneasy. He believed anyone who had amassed a fortune had a moral imperative to give much of it away to the starving masses.7


    Might as well throw it in here, especially since Enlightenment thinkers were infamous for having pretty racist views (which were common in their time).

    Interestingly, Kant, despite saying some pretty awful shit about race early in his career, turned the intellectual corner and realized later in his life that no race has any right to subjugate any other. It makes sense, after all: racism and other forms of bigotry are textbook cases of treating other people as means rather than ends.8

    Kant came to the conclusion that if all rationality is sacred, then there’s nothing permitting Europeans’ special privileges over any other nations or races. He also became vehemently anti-colonialist. Kant argued that regardless of race, the violence and oppression required to subjugate populations would destroy people’s humanity in the process. It was the ultimate unethical institution.

    This was radical for the time. Radical to the point of being considered absurd by many. But Kant reasoned that the only way to prevent war and oppression was to form an international government that organized and bound nation-states together. Centuries later, the United Nations would be largely based on his vision.

    The Duty of Self-Improvement

    Most philosophers of the Enlightenment believed that the best way to live is to increase happiness as much as possible, and to reduce suffering as much as possible. This approach to ethics is called ‘utilitarianism’ and is still the predominant view held by many thinkers today.9

    Kant had a completely different take on how to go about improving the world. Let’s call it The Michael Jackson Maxim. Because Kant, like Michael, believed that if you want to make the world a better place, take a look at yourself, and make that change. Hoo!

    But instead of grabbing his crotch, Kant made his argument with brutal rationality. Here’s how he argued it:

    • Kant believed that, generally, it is impossible to know whether a person deserves to be happy or suffer because you can never truly know what their intentions and aims were when they acted.
    • Similarly, even if you should make others happy, there’s no way to precisely know how to make them happy. You do not know their feelings, values, or expectations. You do not know the implications your actions will have on them.
    • On top of that, what actually constitutes suffering or happiness, in most non-extreme situations, is unclear. Your divorce may cause you incredible pain today, but in a year it may be the best thing that ever happened to you. You may relish the joy of celebration with friends, but maybe it’s distracting you from pursuing something that would prevent more future suffering.
    • Therefore, Kant argued, the only logical way to improve the world is through improving ourselves. This is because the only thing we can truly experience with any certainty is ourselves.10

    Kant defined self-improvement as developing the ability to adhere to the categorical imperative. And he saw self-improvement as a duty—an undebatable obligation put on us all.

    To Kant, the reward/punishment for not following one’s duty was not in heaven or hell, but in the life one made for oneself. Adherence to morality produced not only a better life for yourself but a better life for all of those around you. Similarly, failure to adhere to morality would produce unnecessary suffering for oneself and for those around you.

    Kant’s Rule has a ripple effect. Your improved ability to be honest with yourself will increase how honest you are with others. And your honesty with others will influence them to be more honest with themselves, which will help them improve their lives.

    This is true for all aspects of Kant’s Rule, whether it’s honesty, productivity, charity, or consent. The Michael Jackson Maxim suggests that Kant’s Rule, once adopted by enough people, will generate a snowball effect in the world, enacting more positive change than any calculated policy or institution.

    The Duty of Self-Respect

    Kant intuitively understood that there is a fundamental link between our respect for ourselves and our respect for the world. The way we interact with our own psyche is the template which we apply to our interactions with others, and little progress can be made with others until we’ve made progress with ourselves.

    He would likely be disgusted with the self-esteem movement today, seeing it as just another way of treating people as means to some end of feeling better. Self-respect isn’t about feeling better. Self-respect is about knowing your own value. Knowing that every human, no matter who they are, deserves basic rights and dignities. That every consciousness is sacred and must be treated as such.

    Kant would argue that telling ourselves that we are worthless and shitty is just as wrong as telling others that they are worthless and shitty. Lying to ourselves is just as unethical as lying to others. Harming ourselves is just as repugnant as harming others. Self-love and self-care are therefore not something you learn about or practice. They are something you are ethically called on to cultivate within yourself. Even if they are all that you have left.

    The Impact of Kant’s Philosophy

    Kant’s philosophy, if you dive into it, is riddled with inconsistencies and issues. But the power of his original ideas has undoubtedly changed the world. And strangely, when I came across them a year ago, they changed me.

    I had spent most of my 20s pursuing many of the items on the list above, but I pursued them for practical and transactional reasons. I pursued them as means because I thought that they would make my life better. Meanwhile, the more I worked at it, the emptier I felt.

    But reading Kant was an epiphany. In only 80 pages, Kant swept away decades’ worth of assumptions and beliefs.11 He showed me that what you actually do doesn’t matter as much as the purpose behind doing it. And until you find the right purpose, you haven’t found much of anything at all.

    Kant wasn’t always a humdrum, routine-obsessed dork. He wasn’t always the mayor of Boreville. In fact, in Kant’s younger years, he was a bit of a party hound as well. He would stay up late drinking wine and playing cards with his friends. He’d sleep late and eat too much and host big parties.

    It wasn’t until he turned 40 that he dropped it all and developed the routine life he later made famous. He said that he developed this routine at 40 because he realized the moral implications of his actions and decided that he would no longer allow himself to waste the precious time or energy his consciousness had left.

    Kant called this “developing character”—a.k.a., building a life designed around maximizing your own potential. He believed most people can’t develop true character until they reach middle age, because until then, they are still too seduced by the fancies and whims of the world, blown this way and that, from excitement to despair and back again. We’re too obsessed with accumulating more means and are hopelessly oblivious to the ends that drive us.

    To develop character, a person must master their own actions and master themselves. And while few of us can accomplish that in a lifetime, Kant believed it’s something we each have a duty to work towards.

    In fact, he believed it was the only thing to work towards.


    1. Fun fact: Isaac Newton also never saw the sea, despite also only being hours away. What’s even more incredible is that Newton is the one who discovered that the moon’s gravitational force is what caused the tides. And he figured that out without ever actually seeing the tides.
    2. Derek Parfit, the famous professor of philosophy at Oxford called him the most important moral philosopher since the ancient Greeks.
    3. Einstein read Kant’s Critique of Pure Reason as a teenager and said that it was formative in how he approached questions of physics.
    4. Kant argued that anything possessing consciousness and autonomy possesses an inherent dignity and must be treated with respect (i.e., cannot be harmed). Kant believed that animals did not have consciousness or free will, but claimed that if they did, then they would deserve the same level of respect as humans. Interestingly, Kant also made the same point about aliens.
    5. This rule is known as Kant’s “Formula for Humanity.”
    6. I would have loved to know what Kant would say about social media and video games.
    7. My guess is that if he lived today, Kant would support Universal Basic Income.
    8. Sadly, somehow Kant never came to these same obvious conclusions about women. That’s probably why he remained single his whole life.
    9. Sam Harris, Tyler Cowen, Steven Pinker, and Peter Singer are some prominent utilitarians.
    10. And I would argue that modern psychology has even called this into question.
    11. The book I’m referring to is Fundamental Principles of the Metaphysic of Morals. Enjoy!