If it looks like a duck, swims like a duck, and quacks like a duck, it’s probably a duck.

You can determine a lot about a person by observing their habitual actions and characteristics.

When someone tells you who they are, believe them the first time.

A “razor” is a rule of thumb that simplifies decision-making.

Humans are wired to take shortcuts in our decision-making. These shortcuts can lead us astray—but when used appropriately, the shortcuts can be extremely valuable.

Here is a list of powerful decision-making razors to help y...

If you have a choice between entering two rooms, choose the room where you're more likely to be the dumbest one in the room.

Once you're in the room, talk less and listen more.

Bad for your ego—great for your growth.

Nassim Nicholas Taleb famously proposed this rule of thumb in his best-selling book, Skin in the Game.

He talks about choosing between two surgeons of equal qualification and experience. One looks highly refined and one looks like a butcher.

If forced to choose between two options of...

Make decisions that your 80-year-old self and 10-year-old self would be proud of.

Your 80-year-old self cares about the long-term compounding of the decisions of today.

Your 10-year-old self reminds you to stay foolish and have some fun along the way.

When you make decisions wit...

When deciding what to read, just read whatever grabs you. When it stops grabbing you, put it down.

Avoid the trap of only reading “impressive" sounding books that bore you to death.

Never establish reading vanity metrics as goals.

Time is either *invested* or *spent*.

Invested time—actions that compound:

• Reading
• Physical activity
• Mindfulness
• Relationship building

Spent time—actions that don’t compund.

When choosing what to do, prioritize investing time, not spendin...

Anything asserted without evidence can be dismissed without evidence.

If something cannot be settled by reasonable experiment or observation, it's not worth debating.

These will save you from wasting a lot of time on pointless arguments.

Opinions are earned—not owed.

If you can't state the opposition's argument clearly, you haven't earned an opinion.

 There's a natural human tendency to feel the need to have an opinion on absolutely everything. When asked about a topic you don't understand deeply, take pride in having...

If you encounter someone with opinions or perspectives very different from your own, listen twice as much as you speak.

Our natural tendency when we hear a view we disagree with is to respond and refute it.

Instead, always default to Listen Mode. You'll learn way more that way.

Too many people take on stress that has no upside.

If something is going to be stressful, consider whether the reward is sufficiently outsized to justify the stress.

If it isn't, don't take it on.

Complexity and jargon are used to mask a lack of deep understanding.

If you can’t explain it to a 5-year-old, you don’t really understand it.

If someone uses a lot of complexity and jargon to explain something, they probably don’t understand it.

Truly successful people rarely feel the need to brag about their success.

If someone regularly brags about their income, wealth, or success, it's fair to assume the reality is likely a small fraction of what they claim.

If they consistently name-drop important people with no relevant ...

When in doubt, choose to show MORE gratitude to the people who have mentored or supported you.

Say thank you more. Tell someone you appreciate them. Not just on special occasions—every single day.

Lean into gratitude daily and your life will improve.

When you're weighing alternative explanations for something, the one with the fewest necessary assumptions should be chosen.

Put simply, the simplest explanation is often the best one.

Simple Assumptions is greater than Complex Assumptions. If you have to believe a co...

If you have the choice, always choose to sprint and then rest.

Most people are not wired to work 9-5—long periods of steady, monotonous work. It's a remnant of the Industrial Age.

Parkinson’s Law states that work expands to fill the time available for its completion. When you establis...

If your smartest friends are all interested in something, it’s worth paying attention to.

If that something seems crazy, it's worth paying a lot of attention to.

The passions and weekend projects of the smartest people in your circles are a looking glass into the future.

Never attribute to malice that which can be adequately explained by stupidity.

In assessing someone's actions, we shouldn't assume negative intent if there's a viable alternative explanation—different beliefs, lack of intelligence, incompetence, or ignorance.

Applies to politics, rela...

If you're struggling to understand something, try writing it out.

When you write, you expose the gaps that exist in your logic and thinking. Study to fill the gaps.

Writing is the ultimate tool to sharpen thinking—use it as a "knife block" for life.

When faced with two paths, choose the path that puts you in the arena.

It's easy to throw rocks from the sidelines. It's scary and lonely in the arena—but it's where growth happens.

Once you're in the arena, never take advice from people on the sidelines.

When choosing between two paths, choose the path that has a larger luck surface area.

Much of what we call "luck" is actually the macro result of 1,000s of micro-actions.

Your daily habits put you in a position where “luck” is more likely to strike.

It’...

When deciding whether to take on a new project, follow a simple two-step approach:

Is this a "hell yes!" opportunity? If not, say no. If yes, proceed to Step 2.

Imagine that this is going to take 2x as long and be 1/2 as profitable as you expect. Do you still want to do it? If no, say...