The Philosophy of Everything 2e — Part I, Ch 4: Rationality

Irrationality is not stupidity. It is signing for whatever your mind hands you without opening the package, and some of the cleverest people I have met never open it.

In brief: In this chapter I describe one small habit: looking once more at a conclusion before you take it as yours. I separate the private kind of rationality from the kind many minds can share, and show the three shapes our reasoning takes. Then I walk through the traps the mind falls into when the looking is skipped. It matters because a life run on unchecked conclusions keeps paying for them, and because this habit, done often enough, is what wisdom actually is.

Imagine a small moment in the life of the mind. Something has just come in: a story you heard, a face on the news, a sentence you remembered from a book. In less than a second, your mind has done something with it. It has produced a conclusion about it. The conclusion is now sitting in your hand. You can look at it. You can question it. You can ask where it came from, and whether you would still believe it if it had come from someone you disliked. Or you can take it as yours, without looking, and keep walking. Most of the time, most people take it without looking. That taking-without-looking is what irrationality actually is. The looking that almost never happens is what rationality is.

I was a person who did not look, for a long time. By my mid-twenties I had read enough philosophy to recognise an argument when I saw one. What I had not yet built was the habit of using any of that on what was actually arriving in my own head. The tools sat on the shelf. The mind in here kept handing me conclusions, all day, every day, and I kept taking them. Mostly I took them because the taking was faster than the looking. Partly it was because I had never been shown how to do the looking. The looking is a small thing, and not difficult, but it is also not obvious.

The last chapter was about what knowledge is and how to test it. This one is about what to do on an ordinary day, when knowledge is not the question and the mind is just busy handing you things. The mind is generous in this way. It hands you many things. The question this chapter is asking is whether you would like to start looking at what is in your hand before you take it as yours.

To be rational, in the simplest words I can find for it, is to do one small thing well, again and again, for as long as you live. Before you accept any conclusion as yours, you look at it once more. You look before you act on it, before you tell it to someone else, before you organise even a small piece of your life around it. You ask where it came from. You ask what would have to be true for it to be wrong. You ask whether you would still believe it if you had heard it from someone you disliked. That looking is the whole of it. It is also harder than it sounds, because the brain hates the extra work. It would much rather hand you the answer it already had and move on.

Let me describe the absence of this habit first, because the absence is what makes the habit visible. Irrationality is not the same as stupidity. Some of the most irrational people I have met have been clever ones. Irrationality is what happens when a person takes a conclusion into their head without looking at it. Then they arrange their life around the unchecked thing as though it had been checked. They feel certain. They might be right. They might be wrong. They have not done the small piece of work that would let them tell which. Sometimes the world punishes them for it. Sometimes it does not. The ones who never run into a wall keep the unchecked thing for life. The ones who do run into a wall sometimes change their minds, and sometimes refuse to, even then.

What makes this so dangerous is that irrationality looks like rationality when enough people share it. A confidently held wrong belief, held by everyone you grew up around, will feel exactly like a confidently held true belief. From the inside, you cannot tell the difference. From the outside, the only difference is what each belief touches when it is pressed against the world. The unchecked one gives way. The checked one holds. By the time a person finds out which kind they had been carrying, they have often arranged a great deal of their life around it.

Evolution, slowly, favours the looking kind of mind. Not always. Not by enormous margins. But over time, a creature that can change its mind in response to evidence outlasts a creature that cannot. The world keeps moving. The conditions a belief was built for keep shifting. A mind that can let an old answer go when the answer no longer fits the world is a mind that survives the world's changes. A mind that grips the old answer and waits for the world to change back tends to wait until the world has moved on without it. This is not a moral preference. It is just what survives. Being non-possessive of your own beliefs is, in the long run, an instinct for staying alive. By non-possessive I mean holding a belief loosely, as something you are using, not something you own.

One of the first things I had to figure out about this looking work is that it comes in two kinds. The two kinds line up roughly with the two kinds of truth I described in Chapter 1. Once you can feel the difference between them, several arguments that had felt impossible to settle start to make some sense.

The first kind happens inside one head and only matters to the person inside that head. Philosophers sometimes call this subjective rationality, which is a long name for a simple thing. The conclusions in question are about a single life, and only the person inside that life can really inspect them. The mind hands someone a conclusion about whether to leave a well-paying job to be near a dying parent. From outside, the conclusion might look unreasonable. From inside, with full access to what only that person can see, it might be the most reasonable thing they have done in years.

The mind doing the looking is running on its own private mix. The mix is made of the tendencies the person was born with, the things they were conditioned into by the people around them, and the consequences of what they have already chosen. Call those three things mental modifications, since the next chapter will use the word. The point for now is just that the mix is private. Only the person inside it can really see what their mind is handing them.

I want to be careful, though, because the same private materials can also produce reasoning that has gone badly wrong. A person who ends their own life believes, in that moment, that the act is the most reasonable response to what they are carrying. The act is not reasonable. It is the conclusion of a mind that has run out of room to see the other options that, from outside, are still there. It is reasoning done with a damaged tool. It is a tool that the rest of us, if we could see what it was working with, would gently take from the hand and put down. This is one of the reasons a person in that state should never be alone with the conclusions of their own reasoning. The materials inside one head are sometimes the very thing that has gone wrong. And the head that contains them is the last place equipped to do the looking.

The other kind of rationality is the one many minds can do together. Sometimes the conclusion is not about one private life but about something the rest of us can also examine. It might be what counts as healthy blood pressure, whether a stranger should help a child in danger, or whether the climate is changing. When that is so, the looking can be shared. You take a million people's readings. You find that the safe blood pressure range sits between ninety over sixty and a hundred and twenty over eighty. That number is not anyone's opinion. It is what fell out of many people's readings being added up honestly. This second kind of rationality, the kind we can share, is sometimes called objective.

You can do the same with behaviour. Imagine someone watches a child fall into a fast-moving canal. The person on the bank is not the child's parent. There is no obvious threat to their own life if they walk away. What is the reasonable thing for them to do? You cannot answer this from inside one head. You can answer it by asking, of a thousand thoughtful people, what they would do. If most of them say they would try to save the child, then trying to save the child is what we have collectively decided is reasonable in that moment. A person who walks away has not broken any law in most places. They are, however, behaving in a way the rest of us, after careful reflection, would not call reasonable. That is what shared rationality is: the agreement, slowly arrived at, of many considered minds about what makes sense to do.

The trouble with the shared kind of rationality is that the agreement is sometimes wrong, and often slow. The majority is sometimes mistaken, especially about changes that happen too slowly to feel. Climate is the obvious case in our lifetime. The carbon in the air rises a little each year. The average person cannot feel it. So the average person, asked whether the climate is in trouble, may say no. That is because their own senses, their own day-to-day weather, do not show them the problem. The slowness fools them. The majority opinion is wrong. The small group of scientists with the instruments to actually measure the change is right.

The same thing happened for centuries with the question of whether the earth went around the sun. The majority of people in Europe, including most of the learned ones, were certain the sun moved across the sky. The few who had checked, with telescopes and careful mathematics, were dismissed. It took the majority several lifetimes to catch up with what a few had already worked out.

Think of the delay between when the careful people figure something out and when the majority accepts it. This kind of delay is one of the most expensive things our species does. People die in the gap. The plague spreads. The river poisons the village. The climate keeps warming. Eventually the truth catches up and is grudgingly accepted. By then the cost has been paid. The point is that the shared kind of rationality, useful as it is, is slow. The work of any one careful person is not to wait for the majority. The work is to do the looking yourself, now, with what you already have.

A small example of this from where I grew up: for thousands of years, Indians used a solar calendar. Then, two millennia ago, somebody noticed that a calendar tracking both the sun and the moon was more accurate than one tracking only the sun. The lunisolar calendar replaced the solar one. It is still in everyday use in India, even though the Gregorian calendar is the official one almost everywhere. People kept the older one because, when actually checked, it gives better answers than its official replacement. That is what the looking habit, sustained over many lifetimes by many ordinary people, ends up looking like. I should say that historians of Indian astronomy tell this story differently. They find that the oldest Vedic calendar already followed both the sun and the moon, and that solar calendars, like Kerala's own Malayalam calendar, are still in daily use. Most astronomers would also say that, for keeping step with the seasons, the Gregorian calendar is the more accurate of the two.

When I started doing this work seriously, I noticed something about the work of reasoning itself. The mind goes about it in three different shapes. I want to describe them quickly, side by side. None needs much explaining, but seeing the three together is useful, and the looking each one requires is a little different.

Sometimes I would start from a rule I already trusted and walk it down to the case in front of me. All humans die. I am a human. So I will die. This kind of reasoning is sometimes called deductive. It goes in the descending direction, from a general rule to a particular case. The medicine of Āyurveda and the practice of yoga were both built on this kind of thinking, and so was most of classical philosophy. Its strength is that, when the starting rules are sound, the conclusions arrive without argument. Its weakness is that it gives you nothing genuinely new. You already had the rule. You were only walking down from it.

It has a darker way of going wrong, too. When you travel to a place you have never been, the mind hands you assumptions about the people who live there before you have actually met any of them. Some of those assumptions are small and harmless. Some are the seed of every racist generalisation our species has ever made. The reasoning shape is fine. The rule it started from was rotten.

Other times I would do the opposite. I would start from what I had actually seen and try to climb up to the rule that explained it. I would see smoke over the trees, and remember that smoke has always meant fire, and decide there was probably a fire over those trees. I would see that the traffic was heavier this Wednesday than last, and remember that traffic gets heavy when the schools reopen, and decide the schools must have reopened.

This kind of reasoning is called inductive, and it is the engine of modern science. You collect cases. You look for the rule that explains them. You build the rule up from below. Its strength is that it produces genuinely new knowledge. Its weakness is that it is never quite certain. The next case could be the one that breaks the rule. The heavy traffic this Wednesday might not be because of the schools at all. It might be an accident two streets away that you have not yet heard about. The looking on this kind of reasoning is the question: what else could explain what I have seen?

Other times still I would not have the time or the materials for either of the above, but would still have to decide something. The child is unusually quiet when I come in. There are many reasons a child could be unusually quiet. I cannot test each one. So I reach for the most likely. Something has upset her. I go and check. This is sometimes called abductive reasoning. It is the work of picking, from a handful of possible explanations, the one most likely to be true given the little you have.

Doctors do this when a patient walks in the door. Detectives do this with a crime scene. Parents do this hundreds of times a day. It is not certain. It is often wrong. But it is honest about being a guess, and it lets you act when waiting for full certainty would cost too much. The danger in this kind of reasoning is that the brain gets so quick at guessing that the guesses begin to feel like conclusions, and the looking gets skipped. The fix is the same as everywhere else in this work: look at what is in your hand before you take it.

These are the three shapes, then: walking down from a rule, climbing up from cases, picking the most likely. They do different work and live in different parts of a life. None is enough on its own. Picture a mind that switches among them when the situation calls for it. Picture it doing the small extra work of looking at the conclusion each one hands over. That is the mind doing what minds were built for.

Now to what goes wrong. Even with the looking habit in place, the mind has shapes it falls into when the looking is rushed or skipped. I will walk you through a few of them. This is not because you need to memorise a catalogue. You do not. It is because once you have seen each shape once, you start spotting it in your own thinking, and the spotting is most of the work.

The biggest of the shapes, the one that scales up into much of the trouble between groups of people, is the move from one person to many. Malvika notices that her colleague Latika eats vanilla ice cream three times a day, and decides Latika must love it. It is a fair-looking guess. It is also wrong. Latika has lost a bet with her sister Radhika. She has to eat ice cream she hates for a month, and send a selfie as proof. One person's behaviour is not the behaviour of a group.

The same machinery, scaled up, becomes prejudice. One person from a community does something unkind. The mind generalises. The whole community becomes, in the watching mind, the kind of people who do that. The move from one case to all cases is fast and feels natural. It is also wrong nearly every time it is made about people. Communities do not act. People act. A person from a community is one person from that community, no more, no less. The shape of the reasoning is what to watch for. It always looks the same: one case, generalised. The looking on this shape is the question: how much of this conclusion is really about the person I am looking at, and how much is the older picture my mind has reached for?

A different shape of error happens at the other end. It is the move from many causes to one. Climate change has many sources: the cars, the cattle, the factories, the deforestation, the heating, the transport of food across the world. An activist who blames only the oil companies for it is making the same kind of mistake as someone who blames only the cars, or only the cattle. Most things in the human world have several causes braided together. The mind picks the loudest one and calls that the cause. The correction is small. When the mind hands you a single cause for a large problem, look for the others before you take the conclusion.

The third shape is one I had to learn to see in myself before I could see it in anyone else. It is the move from "no evidence against" to "must be true." Many people argue for the existence of God this way. Nobody has proven God does not exist, they say, therefore God does. The reasoning has the shape of a sentence, but it is not actually doing any work. The absence of disproof is not proof. If it were, every absurd claim would be true. There is no evidence against an invisible elephant in your kitchen, no evidence against a goat-god that lives on the dark side of the moon, no evidence against any story I happen to make up between this sentence and the next.

The test of a real claim, as the last chapter said, is whether some piece of evidence could in principle force you to give the claim up. The technical word is falsifiability. It only means that a claim can, at least in principle, be shown to be false. A claim that nothing could refute is not strong. It is empty. It only sounds strong because the speaker has confused invulnerability with truth, and they are not the same thing. A claim that cannot be attacked is not, for that reason, a claim that is true. The strength of a claim comes from its willingness to be wrong, not from its refusal to be checked.

A fourth shape, and one of the most expensive, is the trap of letting the imagination finish a story the world has only just begun. There is a small skirmish at a border. Two soldiers exchange shots. By the evening news this has become "the start of a war." By the morning papers the war has been won and lost and the country has been redrawn. None of this has happened. Only the skirmish has happened. The mind, given a small event, builds a large story from it, and the story feels as real to the mind as the event did. The fix is to ask, at each step, whether the next step has actually happened or has only been imagined. Most of the time it has only been imagined.

The world we live in has whole layers of cause and effect at work that no one in the room can see. I came to call these layers the hidden causal plane, and I will say more about it later. The imagination tends to write the ending of a story before the world has finished writing it. That tendency is one of the main ways we miss what the deeper layers were about to do.

There are smaller shapes, easier to name in passing. The mind sometimes hands you what it thinks it heard before you have noticed it doing so. A sharp sound becomes the television, when in fact a gunshot has gone off outside. The mind sometimes hands you a path you know is the wrong one but tells you to keep walking. It does this because some part of you believes the wrong path will become the right one if you walk it long enough. The same machinery, scaled up, is the basis of much of religion.

The mind sometimes hands you somebody else's word as if it were your own. It might be a friend's word, a GPS's, a stranger's on the internet. And you sign for it without looking at the package. The mind sometimes hands you a forced choice between two options when the actual situation has a thousand options in between. Either guilty or not guilty, either in love or not in love, either with us or against us. And the two-box answer is almost always wrong about the thousand-box thing. The mind sometimes hands you the bystander's conclusion. Since nobody else is helping the person bleeding by the side of the road, helping cannot be the right thing to do. And so nobody helps, and the person dies. Each of these is a small shape. Each has the same cure. The looking that is missing in every one of them is the looking at what your own mind has just placed in your hand.

The biggest shape of all, the one that drives most of the others, is the move of believing something because many people believe it. The majority can be wrong. It has been wrong, again and again, about things that turned out to matter. The majority once believed the earth was flat. The majority once believed disease was caused by bad air. Plenty of people right now still believe that this whole arrangement of galaxies and species, including the person reading this, was made all at once by a being nobody has ever seen. They believe it instead of accepting the careful evidence from many fields that life arrived slowly, over billions of years, through processes you and I can now read about in any library. The simpler story is more appealing. It is also wrong.

The majority opinion is not, by itself, evidence of anything except that an opinion is widely held. Whether the opinion is true is a separate question, and a much harder one. Anyone who tells you something is true because everyone believes it is asking you to skip the only check that matters.

There is one last thing I want to say about all this, because it ties the chapter together and points at what is coming.

The looking-before-taking work is hard at first and easy later. The first hundred times you try to do it, you will forget about half of them. The second hundred, you will forget less. After a few years, the looking happens without your noticing. It is like a driver who has driven the same road every day for ten years and no longer thinks about each turn. The brain learns this the way it learns any habit, by repetition, until the road in the head has been carved. What was once effort becomes second nature. This is what wisdom actually is. Not a beard, not a robe, not a set of secret teachings. Just the looking habit, done so often that it has stopped being a separate act from thinking itself.

Education, real education (not the collecting of degrees and certificates that much of school has become), is what builds this habit in a young mind. A school that produces looking-before-taking thinkers does not have to teach religion, or virtue, or morality directly. The habit takes care of those on its own. A person who looks twice at what their mind hands them is also a person who looks twice at the conclusion that the people across the river are less than them. They are also a person who looks twice at the urge to take more than they need. They are also a person who, when their faith is on the line, looks twice at the faith. This is why I have come to think that education, done properly, is the real baptism. It is the one ceremony that actually changes a person into something more humane. It takes away the artificial walls our cultures keep building between groups of people. Once a child has been taught to look, the walls become harder to build inside them.

I want to be careful about something here. Some of the worst things done in human history have been done by people who were certain of one thing. They were certain they had figured out, once and for all, what a perfect human society would look like. They tried to build it, and many millions of people died in the building. There is no perfect society waiting to be built. That is because the people who would have to live in it are at every different level of awareness, at every different stage of working out their own confusions. A world without harm is not coming. What is possible is a world in which more people, slowly, take the looking habit into their own lives. In that world they try to be a little happier in those lives, without becoming an obstacle to anyone else's happiness. That is the most you can reasonably ask for. It is also more than enough.

So here is what to do the next time you hear something like this. Someone may tell you that an apple mysteriously appears in a young boy's life when he begins to grow up, to warn him against displeasing God. Or that a piece of fruit eaten in a garden long ago is the reason the whole human species is in pain. Or that there is some unseen entity who will reward you for following its instructions and punish you for not. Do not argue with the person telling you. They are not in a state where argument will help. Just notice, quietly, that there is no way to check the claim, no test that could ever show it false. Notice, too, that this is the same shape as every story human beings have ever told to explain something they did not yet understand. File it under stories. Walk on. The looking habit has saved you an hour of fruitless argument, and possibly a small piece of your own mind that you would have lost trying.

The cost of using the looking habit is the small discomfort of admitting, every so often, that something you had taken for true was not. The cost of not using it is the slow disaster of a life run on other people's unchecked conclusions. It is also the quiet piling-up of consequences that the old word karma names. Karma is the way thoughts and words and actions come back, in their own time, to find the person who set them in motion. A life lived without the looking does not get away with it. It just keeps paying. A life lived with the looking keeps being refunded, sometimes for years.

Knowing how to think well, it turned out, was just the foundation. What is actually there, underneath the many different reports each of us writes about it, was what I had to look at next. So was the question of why those reports differ so widely.

Words to Keep

• rationality: looking once more at any conclusion your mind hands you, before you act on it, repeat it or build your life around it.

• irrationality: taking a conclusion without looking at it, then arranging your life around it as though it had been checked. It is not stupidity.

• subjective rationality: reasoning about a single life, done inside one head, with a private mix that only the person inside it can really see.

• mental modifications: the tendencies you were born with, your conditioning, and the consequences of your past choices, which together make up a mind's private mix.

• objective rationality: the shared kind of looking, where many minds examine the same evidence and slowly agree on what is true or reasonable.

• deductive reasoning: walking down from a general rule you already trust to the particular case in front of you.

• inductive reasoning: climbing up from the cases you have seen to the rule that explains them. It is the engine of modern science.

• abductive reasoning: picking, from a handful of possible explanations, the one most likely to be true given the little you have.

• falsifiability: the mark of a real claim, which is that some piece of evidence could, in principle, force you to give it up.

• hidden causal plane: the layers of cause and effect at work in the world that no one in the room can see.

• wisdom: the looking habit, done so often that it has stopped being a separate act from thinking itself.

• karma: the quiet piling-up of consequences, as thoughts, words and actions come back in their own time to the person who set them in motion.

Sources and Further Reading

• Aristotle, Prior Analytics. The classic home of reasoning down from a general rule, in the "all humans die" pattern I use for deduction.

• David Hume, An Enquiry Concerning Human Understanding. The old problem behind my point that induction is never quite certain and the next case could break the rule.

• Charles Sanders Peirce, Collected Papers of Charles Sanders Peirce. Peirce gave abductive reasoning its name: the work of choosing the likeliest explanation.

• Karl Popper, The Logic of Scientific Discovery. The book behind the word falsifiability and the idea that a claim nothing could refute is empty.

• Carl Sagan, The Demon-Haunted World. His invisible dragon in the garage makes the same point as my invisible elephant in the kitchen.

• Nicolaus Copernicus, On the Revolutions of the Heavenly Spheres (1543), and Galileo Galilei, Dialogue Concerning the Two Chief World Systems (1632). The careful few who argued, with mathematics and then the telescope, that the earth goes around the sun, long before the majority agreed.

• Bibb Latané and John M. Darley, The Unresponsive Bystander: Why Doesn't He Help? (1970). The research on why people in a crowd fail to help, which I call the bystander's conclusion.

• Patañjali, Yoga Sūtras, and the Caraka Saṃhitā. Classic texts of yoga and Āyurveda, the two traditions I name as built on deductive thinking.

• Lagadha, Vedāṅga Jyotiṣa. The oldest Indian text on keeping a calendar. It already follows both the sun and the moon.