Introduction to Reason

Table of Contents

You use your mind to guide your life. You think about every decision you make. Even if the thinking is quick or unconscious, your stomach or heart doesn’t literally make the decision. Your mind is what enables you to learn and use skills. It’s what lets you do activities successfully – and even know what an “activity” is. Your mind is the most important and active part of you.

But how much attention do you give to using your mind in the best, most effective ways? How much effort do you put into good thinking? The best ways to think are called reason. You should use reason instead of whim, faith, hoping, wild guessing, superstition, being guided by emotion, or thinking whatever you’re told to think (following authority).

Tons of people say they’re in favor of reason. Given you’re reading this, I bet you already think reason is good. But have you studied reason? How much effort have you put into developing your reasoning? Are you an expert at reason?

Most people’s knowledge of reason comes from their parents, their school, things they hear (from social media, TV, magazines, books, friends), and some of their own thinking to try to make sense of the world (especially during childhood). Is that good enough? No.

If you have common sense ideas about reason – you just sorta know the default things that most smart people know – then society has let you down. Those ideas are incomplete and contain serious mistakes.

Reason is the most important thing in life. Without it, you have no way to know what’s true or false, real or fantasy, reasonable or unreasonable, fair or unfair, just or unjust. It’s worth the effort to study reason in an organized, methodical way instead of going by hearsay or intuition. If you think you did this in school already, I’ve got some bad news for you: even the best schools in the world are teaching reason incorrectly with the wrong books, the wrong teaching methods, and the wrong ideas. Schools are actually run in fundamentally irrational ways. Sadly, schools are places of authority and groupthink, which confuse students enough that many don’t realize what’s going on.

Don’t take my word for it. Learn about reason and see for yourself.

Purpose of Reason

What’s the purpose of reason. What’s it for? What problem(s) is reason the solution to? What do we expect reason to accomplish? (An important part of rationality is considering the problem/goal/purpose/objective before trying to solve/accomplish/achieve it.)

The purpose of reason is to get good ideas. This comes in two parts: thinking of ideas and judging ideas.

Most possible ideas are errors. Some ideas are false, some don’t work, some don’t make sense. There are bad ideas. So we can’t just think of ideas and accept them all. We need a method for choosing between ideas. We need a way to figure out which ideas are good or bad, useful or useless, right or wrong. That’s what reason is for. (We also need a method for coming up with ideas, but optimizing that is less important than optimizing what we do with our ideas.)

Approaches to Reason

There are many ideas about how to reason correctly. I’m going to talk about what I think is correct (which builds on Karl Popper’s philosophy, Critical Rationalism, which talked about error correction and fallibility). Because reason is so important, I think everyone should be familiar with many schools of thought about reason and make up their own mind. Survey the literature and see what else is out there. And if you think I’m mistaken, I urge you to write down and share your reasoning, or share a link or reference if someone else already did that. Figuring out the right ideas about reason is important and contributions are welcome. If I made a mistake, I’d like to know. And if you made a mistake, you could find out by discussion.

Core of Reason

The core of reason is error correction. Rational thinking uses criticism – explanations of mistakes – in order to find errors and fix them. By continuously working to fix our mistakes, we can improve our ideas. That lets us get better and better ideas, which is progress. Progress is an unending quest; there’s no finish line, and no limit to how far we can go.

We’re never done dealing with errors. There is never any way to guarantee that an idea is true or that a person isn’t making a mistake about some issue. We should seek ongoing progress instead of seeking guarantees that today’s ideas are correct.

(The previous two paragraphs loosely summarize some of Popper’s ideas.)

How do we look for errors? First we have to know what ideas are. Good ideas solve problems in contexts. This needs some explaining:


Consider problems first. A problem doesn’t have to be a bad thing. It’s anything that could be better (an opportunity for improvement and progress). Examples of problems: What’s the answer to this question? How do I accomplish that goal? How do I get and eat a burrito? A problem means anything with room for improvement where you’d like to make a change. Anything you want to know or accomplish is a problem, even if you’re trying to improve something that’s already good. Making things better is problem solving whether the starting point is great or awful.

Good problems have clear success and failure criteria. They define what is a solution and what isn’t. People often leave criteria for success vague, which makes their problems hard to solve.

Don’t try to solve every problem you see. Don’t tunnel vision on the first problems you notice. There are infinitely many problems you could work on. Prioritize important problems, especially if they’re easier to solve. Figuring out what problems to work on is itself a problem.

A solution is a way of making progress on a problem. It’s an idea which addresses a problem: answers a question, achieves a goal, fixes a mistake, etc. Solutions usually work for multiple similar problems, but not for all problems.

Some solutions are indirect. For example, instead of answering a question you might figure out that the question is ambiguous and come up with a better question (which better gets at the issue you care about) to answer instead. The reason indirect solutions work – the reason it can be OK to change the problem – is because you figure out that there’s a difference between the stated problem and the problem you actually have in your life. That’s common. In that case, you can reject the stated problem and try to state a new, better problem which is more relevant to your life.

Good solutions typically explain how and why they work, and address potential objections and doubts. They guide you. If an idea fails to guide you to deal with a problem, it’s inadequate (a partial solution at most – maybe you can salvage it in some way, but it doesn’t work as-is). However, what’s required in a solution depends on the problem. If the problem is simple, e.g. just to name a fact without explanation, then naming the fact solves the problem, though that may be a bad problem.

Some problems are better than others. To decide which problems to solve in your life, you need to consider how they’ll help with your goals and what goals are good to have. Naming facts without any understanding of them will sometimes help with your life, but often it’ll be useless. E.g. if I tell you that Sacramento is the capital of California, you can imagine a context where that fact would be useful information, but most of the time it wouldn’t be useful.

To provide a different perspective, instead of solving problems you can think about accomplishing goals or achieving purposes. The key point is that good ideas are for something instead of just being a piece of data. If an idea had no use, you wouldn’t value it or bother to remember it. You can then evaluate ideas by whether they work: judge if they successfully do what they’re for. Judge if ideas are useful in the way they’re supposed to be useful. (And you can also evaluate whether the thing the idea is for is actually good. Ideas should be useful for a good purpose.)

A context is a situation, like your life in general, your location, and your available resources. Your context includes facts about issues like: What are your moral values? How tall are you? Do you have a car, and where is it, and how long would it take to start driving it? Are you energetic or tired? Do you have a scheduled appointment you have to get to soon or have free time? Are you currently in Sacramento? Where is the closest Apple store? What skills do you have?

Consider the problem, “What’s the best way for you to get to McDonalds today?” The answer depends on the context, such as your location, the weather, whether you have a car, your transportation budget, the time of day, the hours that various McDonalds stores are open, and your preferences (do you enjoy walking?). The solution also depends on the broader world situation (e.g. is McDonalds still in business?).

In a different context, a different solution will be appropriate. For a single problem and a single context, there’s a single truth of the matter about the best solution. But if you use the same sentence in different contexts, the truth will seem to change. E.g. if you ask “Is it raining?” you will find the answer changes over time. That doesn’t mean truth is a fantasy; it just means the question is abbreviated. Written out fully, the actual question is more like: “Is it raining in Elliot Temple’s context at 11:42am on 2020-02-20?” I think this point about interpreting questions in context is pretty simple once you understand it, but it’s caused a lot of confusion for philosophers.

Solutions normally work for multiple contexts but not for all contexts.

Finding Errors

So how do you judge ideas to see if they’re errors or good ideas? You look at whether an idea solves the problem it’s supposed to solve (in context). Does it work? Is it successful? (For what it’s supposed to work for, in the situations it’s going to be used in.)

If an idea doesn’t say what it’s for, then it’s incomplete. You’ll have to figure out the unstated parts or give up and reject the idea. Ideas are commonly incomplete because completeness is too much work and we don’t need divine perfection; we just need ideas that are good enough to work. People can often fill in some gaps. But if you can’t figure out the purpose of an idea – what problem is it a solution for? – then you’ll have to reject it. That’s a really crucial part of the idea! If you don’t know what the idea is supposed to do, then there’s no way to judge success or failure.

If the context of an idea is unclear, that can ruin an idea too. Consider the idea, “Climb the ladder to get there.” That could be a good idea or a bad idea; it depends on the situation. If someone tells you that idea without saying the context (so you can’t tell where “there” is or which ladder they mean), then you’ll have to reject the idea. It’s not useful. It doesn’t offer you a correct idea – a correct solution to a problem in a context.

If an idea passes the initial tests of offering a solution, a problem (or category of problems) and a context (or category of contexts), then you can consider if it works. In that context, will the solution actually solve the problem? If you can’t tell, that means the idea isn’t good enough (as you currently understand it). It’s the solution’s job to tell you why it works and to address your doubts. If it doesn’t do that, then either it doesn’t work or you don’t know enough about it (you weren’t given enough information or you didn’t think about it enough). Communicating full solutions is very hard, so you should expect to frequently have to improve solutions that people share with you (even books aren’t very complete).

If an idea’s purpose involves human action, then it needs to guide that action – tell the person what to do, why and how – or it won’t work. It needs to deal with motivation, doubts, and anything else relevant to human action. If it leaves all that out, it’s incomplete, and a person would have to add the missing components themselves before using it. This makes ideas pretty easy to evaluate: if in doubt, it’s not good enough, at least for acting on in your context (because it should have answered your doubts, explained itself to your satisfaction, etc). Reason involves high standards instead of fudging things and accepting half-understood half-solutions.

How is it possible to get ideas this good? Won’t you just have no ideas at all if you raise your standards this high? Our society in general doesn’t really know how to create ideas that meet a high standard. Fortunately, you can learn more about it by studying reason. There are long, complicated answers.

In short, the trick is to match your ambitions to your abilities. Don’t set goals in your life that are beyond your capabilities. Work your way up, step by step, using good ideas the whole way. Start with good ideas about the basics and build on that. If working exclusively with good ideas seems out of reach to you, it’s because your life is out of your control and you’ve overextended. Don’t try to do things in your life that are way beyond your knowledge. Do things that you can deal with correctly to a high standard, and keep learning more so you can expand what you can handle, but don’t get ahead of yourself and start failing (that won’t help anything).

You can try something ambitious to learn how it goes, or to practice. Then, if it doesn’t work, you haven’t failed because your goal was to gather information, test yourself, or practice. Don’t commit yourself to actually succeeding, now, at something beyond your abilities.

Start with correctness and build on it and you’ll be surprised how effective it is and how fast you make progress. But if you get ahead of yourself and make lots of mistakes, you’ll end up spending most of your time dealing with those mistakes instead of making progress. And when you deal with those mistakes, you’ll make more mistakes. And when you deal with those, you’ll make even more mistakes. Once you exceed your abilities, there are mistakes everywhere and they overwhelm your whole life – which is why high standards seem unachievable. But if you’d had higher standards, you could have avoided that whole mess in the first place, and life could have been considerably easier.

Because the typical life is full of errors built on errors built on errors – and people’s ability to fix errors has been overwhelmed by more errors than they can deal with – they end up giving up and accepting lots of error. That’s an error, too, and it’s a major part of how people begin compromising on reason and end up irrational. (There are some other things that go wrong, too.)


You have to use your judgement. Reason is a method to help you do it well. It doesn’t tell you exactly what to do, step by step, so that you could mindlessly follow it. It’s more like tips and guidelines for thinking, plus some details about how thinking and learning work. There are no guarantees that you’ll judge ideas correctly. Reason is humanity’s understanding of what ways of thinking are effective and what aren’t (e.g. don’t use superstition, faith, or authority).


Reason is our method of evaluating ideas, which we need because some ideas are mistaken. The core idea of reason is error correction. Good ideas specify their purpose and are judged by whether they succeed at that purpose. The idea itself should help you see whether/why/how it’ll work, which makes evaluation easier since it tells you everything you need to know (if it doesn’t, evaluate it as inadequate). The purpose of an idea also needs to fit into your life or the idea won’t be useful for you.

Common ideas people have about reason contain mistakes and it requires study, and usually discussion, to develop the skill of thinking rationally. Life presents challenges; without reason you’ll fail a lot (without even recognizing most of the failures as failures). The stakes are your life. Reason – the right way to use your mind – is the key to your life. Don’t neglect it.