There is one rule that all the rules in the world follow: every rule has its application condition.

No rule is one-fits-all. No matter it’s a rule of physics, chemistry, biology, mathematics, engineering, social science, psychology, philosophy, mental models, or just “life advice” in general, as long as it describes how something works, it has its application condition.

This is the rule of all rules.

---

Examples: life advice that contradicts each other

Every life advice sounds super legit, until you realize you never really used them. It’s because these rules miss application conditions, so a lot of them actually seem to contradict each other. Here are some:

• “Money can’t buy happiness.” vs. “Most of your problems could be solved by money.”
• “The mother of success is failure” vs “The mother of success is success.”
• “Good things come to those who wait.” vs. “The early bird catches the worm.”
• “You can’t judge a book by its cover.” vs. “First impressions are everything.”
• “You’re never too old to learn.” vs. “You can’t teach an old dog new tricks.”
• “The squeaky wheel gets the grease.” vs. “Silence is golden.”
• “The more, the merrier.” vs. “Less is more.”
• “Honesty is the best policy.” vs. “A little white lie is necessary.”
• “Practice makes perfect.” vs. “Nobody’s perfect.”
• “Curiosity killed the cat.” vs. “Knowledge is power.”
• “Good things come in small packages.” vs. “Size matters.” (yes, I mean Doritos too).

But the full version with application conditions should be:

• “Money can’t buy MORE happiness, IF it exceeds a certain point.
• “The mother of success is failure, IF you are at the early stage.”
• “The mother of success is success, IF you want to snowball to bigger success.”
• “Good things come to those who wait, IF you want bigger worms, and there are bigger ones coming, and you got the time.”
• “You can’t judge a book by its cover, BUT since this is learned, try to make good first impressions too, as it is the default.”
• “You’re never too old to learn, IF after trying you find you can’t pull a new trick, then give this one up and move to the next one.”
• etc.

A lot better huh?

The self-help industry is also confusing to many:

• “You are enough” vs “Stay motivated”
• “Live in the now” vs “Plan for your future”
• “Live every day like it’s your last” vs. “Save for a rainy day”
• “Appreciate what you already have” vs “Keep improving for better”
• “Stop caring about what others think” vs “Listen to others’ advice”
• “Explore as many as you can” vs “Play the long game”

The full version with application conditions should be:

• “You are enough in the sense that you don’t need to be better to DESERVE LOVE” vs “Stay motivated, so you can LIVE A BETTER LIFE”. See? Totally different aims, no contradiction at all.
• “Live in the now FOR MOST OF THE TIME, as it makes you more alive” vs “BUT REGULARLY plan for your future, so you can live better.” See? It’s not black or white, you need both, just different timing.
• “Live every day like it’s your last, not in the sense of spending all your money and make love to death, but in the sense that you need to do the things that really matter instead of waste your life” vs. “Save for a rainy day, so you can smooth out the setbacks.” See? They actually aim at the same thing – live a better life.
• etc.

---

Examples: subjects and mental models

Newton’s Law of Motion. It is applicable only when the object is big enough and moving way below light speed. It doesn’t work on the small scale of atoms and molecules when quantum mechanics comes in handy.

First Principles Thinking vs Standing on the shoulders of giants. These two can live together. We need to think critically based upon the fundamental truth (First Principles), if what the giants have already figured out falls into this fundamental truth circle, then it’s all good, but even if it’s not, we can test out their advice for ourselves.

The 80/20 rule (Pareto Principle). This falls into the distribution patterns field in probability theory. To put it simply, if the distribution is something like normal distribution, then we could say it fits the 80/20 rule. For example, people’s wealth in America. But if it’s something such as logistic distribution, then the 80/20 rule no longer fits.

Law of Diminishing Returns.
Related to scale, most important real-world results are subject to an eventual decrease of marginal returns. But this law only applies in the short run, as in the long run, all factors could change.

Compounding. Compounding is always subject to physical limits and diminishing returns.

I’ll save the page here, you get the idea.

---

Examples: applying rules in the wrong situation

“There is no such thing as knowing without doing. Knowing is doing. If you don’t do it, then you don’t really know it.”

—— Yangming Wang

The gap between knowing and doing is the application condition.

Let’s see some examples of applying the right rule in the wrong situations.

Choose the right path vs Work hard. Most people are told by their parents that hard work is the key to success, so they do whatever job they got, often jobs they don’t like, work their ass off and hope one day they can be rich. Oops. Are their parents wrong? Not really. But what their parents didn’t tell them is that choosing the right path is 10X more important than working hard. Choice comes first, hard work comes second.

Explore vs Focus. Trying out relationships with a lot of different girls is exciting, and it’s almost a must. But only when you are young. After trying for a while, we need to go deep with someone. Because the deep kind of bonding is only possible when you put that much time into that relationship.

Money is a must vs Health comes first. When you are in your 20s or 30s, the whole of society is telling you to do more, do faster, and do harder, so you can make more money and have that house or car, or purse. Even you tell yourself this, so you work overtime a lot but exercise a little. This is wrong? Not really, it depends on if you go beyond a certain limit. The only people who advise otherwise are your parents. They don’t care how much money you make, because they know that trading health for money is never a good deal.

---

We follow other people’s advice all the time, in all aspects of life, without asking one simple question first:

What’s the application condition of it?

---