You should care less about practical advice

After twenty years of writing, I’ve developed a feeling for what my audience wants. I don’t always deliver, but I have, at the very least, a strong intuition whether an essay I write is going to have broad appeal or be mostly read by a handful of fans.

The biggest factor that drives this distinction, in my experience, is an essay’s practicality. Since my writing isn’t pure entertainment, it has a much narrower audience if it isn’t obviously useful.

I get it. Everyone is busy. You’re here today looking for ideas and advice that may change your life. Why spend a lot of time learning about something that isn’t even practical?

I think this is a mistake.

If you actually care about usefulness, spending most of your time learning “advice” or “tips” is counterproductive. Instead, you’ll do better if you spend most of your time understanding fundamental principles.¹

Why Impractical Knowledge is More Efficient

Imagine knowledge is like a tree:

At the base of the tree are principles. These are the things that are least contingent on specific states of the world, and are most generally true. This category includes stuff like F = ma or the conservation of momentum or energy.

These principles are general, but they’re also insufficient by themselves for a lot of situations you care about. You need to know a lot more than just F = ma to design a good bridge or rocket ship. So, as we travel up the trunk, we get to branching points. These represent splits in the state of the world.

For example, while it is true that heavier objects and lighter objects fall at the same speed. We have domains where air resistance is practically irrelevant (lead ball vs solid gold ball), and domains where this becomes a noticeable factor (feathers vs rocks).

As you learn more about the specific, concrete situation you’re in, you branch more and more until you finally come to the leaves of the tree.The leaves of the tree are practical advice. They’re the kinds of “tips” you might give someone who doesn’t know much about a particular domain, deep down, and just wants to know what sorts of action they should take. This would be things like, “make your propeller blades exactly this shape to minimize air resistance.”

Here’s a first observation: there are far more leaves than there are trunks. Each leaf only covers an incredibly narrow subset of possible states of the world, so to reasonably “cover” much of the space of possibilities you need to learn tons and tons of different advice for different cases.

This suggests if you want to maximize your breadth of usefulness, meaning the number of concrete situations advice applies to, you’re better off learning lower down the tree of knowledge, to ideas and knowledge that are less dependent on specifics.

Some Examples

Let’s try this analogy with a few examples.

Consider a goal of getting in shape.

The leaves would be a particular workout plan you decide to follow. Further up the branches, would be principles like progressive overload and recovery. Towards the trunk, you’d have more basic ideas like energy metabolism, muscle and cardiac physiology and so on.

Following a specific workout plan is fine, as long as your situation conforms closely enough to the situation being advised. But what if the workout plan was made for a serious athlete in their twenties, whereas you’re 55 and recovering from an injury? Then, the advice itself is unlikely to be applicable, and may even be counterproductive.


In contrast, the knowledge of more basic principles would still apply, and could steer you to advice on a new branch of the tree of knowledge.

Or consider starting a business.

The leaves are particular tactics like “buy ads on Facebook” or “cold call purchasing managers at mid-sized firms.” Again, if you’re in the domain where this advice applies, perhaps because you’re receiving it from someone in a very similar business, this may be what you need to hear.


But, if you’re not, chasing these tactics may be counterproductive. Instead, you should focus on ideas further down the trunk. A little further down the tree are basic ideas of entrepreneurship like “product-market fit” “minimum viable product” or “market research.” And towards the base you have even more basic concepts like “supply and demand.”

Or consider the topic I write most about: effective learning.

If you’re studying for an exam, then advice for how to pass your particular exam would be the leaves. Further down the branches are somewhat more general ideas for tackling multiple choice questions or organizing your studying materials. Finally you get to bedrock ideas about learning like the spacing effect or retrieval practice.

The latter are most universal, even if they leave degrees of freedom for how you should actually deal with any particular situation.

Dealing with Some Objections

There are a few common objections to focusing on principles over practicalities:

First, there’s the objection that principles don’t constrain decision-making enough. That much is true. Rarely does learning a deep principle give you all you need to know to decide the best course of action in a concrete situation. Usually there’s too many other considerations at play.

But, learning principles is still more efficient. It’s just that sometimes it needs to be supplemented with more knowledge to get you to the correct answer.

To continue our arboreal analogy, imagine you’re trying to find a squirrel in a tree. Saying “he’s on the third branch from the right” doesn’t tell you exactly where he’s located, but it does give you a starting place to look. In contrast, only knowing whether or not he is on a particular leaf is only helpful if he actually is on that leaf—in most cases, that information doesn’t limit your search very much. Directly applicable advice is only helpful if it actually describes the situation you’re in.

Second, there’s the objection that the principles don’t actually describe the world. The theoretician has come up with an elegant-sounding principle that doesn’t actually give useful advice in the domain of practical concern.

This is an issue, but it’s more typically the case that the principles are still largely undiscovered or don’t satisfactorily constrain the problem. This is like a map of knowledge where we can see a bunch of leaves, but don’t really know the location of all the branches underneath the canopy. We guess at some, but maybe those guesses are wrong.

This is correct, as far as it goes. In domains where principles strongly determine the practical advice, such as physics and engineering, there’s a strong rationale for learning the fundamental principles. In domains where principles only weakly determine the practical advice, say entrepreneurship or second language learning, then they’re still worth learning, but they’ll have to be supplemented with a lot more situation-specific advice.

But this isn’t really a negation of the idea that principles are more efficient. It’s simply the case that sometimes we don’t know what the principles are, and so only practical advice can be generated.

Finally, there’s the possibility that figuring things out from fundamental principles is intractable, and so we have to go by practical advice. 

Continuing our analogy, the closer to the trunk you go, the more mental work needs to be done to figure out where the branch points are and where the leaves end up.


This is also a fair critique, and it’s one reason why we have hierarchical domains in the first place and everything isn’t just quantum mechanics. But this simply means that for really complicated domains, we occasionally need more knowledge from higher up the tree to make the principles useful. But because the span of the principles is broad, they still tend to be more efficient for learning.

Applications for Real Life

Applying this idea reflexively, we can see the idea of “learning principles is more efficient than practical advice” is itself a deeper principle. So, what are the practical consequences?

Consider the raft of practical advice book on topics like productivity, diet or personal finance. How many of these are just leaves? The new “fat-busting” diet plan that will have you losing fifteen pounds in fifteen days. The specific habits your favorite author uses to write books. The budget plan for retiring by 45. And so on.

If you were only going to read one book, perhaps one practical book would be best. After all, the fundamental principles don’t sufficiently constrain advice, so, yes, they won’t give you something to do. Whereas if you buy one of these books, maybe you happen to be in the exact situation the author describes and thus can benefit from their advice?

But if you’re going to read more than one book, don’t start there. If the trunk of the tree is largely within an academic field, such as nutrition or psychology, read a textbook. If the trunk of the tree is within the scope of some professional practice, read a book that aims to give the basic information in an unbiased way. “For Dummies” and other general readers are good examples.

Even more generally, make it a personal maxim to try to read as much as possible of the “trunks” of various domains of knowledge. Then, when you do have a practical problem that requires detailed knowledge of the leaves, you may still have some work to do, but at least some of the most important learning will already have been completed.

1. Even though this essay itself is likely to be less popular as a result (i.e., it’s about a deeper idea, not a “tip”) hopefully a few readers will enjoy it.