What the advice to change your mind is really about

One of the most repeated pieces of advice in personal development has a theory behind it that few people have ever heard of. You’ve probably come across the advice many times. Some people call it adaptability. Some call it the ability to learn, unlearn and relearn. Others call it strong opinions, weakly held, or simply the courage to change your mind. They’re all more or less the same idea in different costumes.

At its centre is the willingness and ability to let go of an old idea, whether it’s a self-limiting belief about yourself or a theory about how something works, and to replace it with a better one.

There’s a reason this advice keeps showing up, and it has to do with epistemology, the study of what knowledge is and how it grows.

Most of us would agree with this advice in principle. In practice, though, changing our minds is often uncomfortable, because it can feel like admitting we were wrong all along. But once we understand how knowledge grows, changing our minds stops feeling like something we think we should do and starts feeling like something we want to do.

What knowledge actually is

We tend to operate with an unspoken theory of knowledge. We think of it as a collection of proven facts, things we can be certain of, usually handed down by someone with authority, whether that’s a parent, a teacher, or an expert.

But the best explanation of knowledge we currently have suggests otherwise. Critical rationalism, pioneered by Karl Popper and developed further by David Deutsch, says that knowledge is provisional. It’s conjecture, our current best guess, and it grows each time we find and correct an error in it. While critical rationalism isn’t final or complete, and by its own logic never will be, its core ideas apply as much to a decision about your career as they do to a scientific theory.

A few of its core principles include:

• All knowledge is fallible. No explanation is ever final or free from error, no matter how well established it may be. In everyday terms, this means any mental model you hold about yourself, your work or how to live well is your current best conjecture, and every conjecture can be improved.
• Knowledge grows through conjecture and criticism. We generate creative conjectures to explain phenomena, then subject them to rigorous testing via rational criticism. This process, known as error-correction, is how knowledge improves over time. In our own lives, it looks like taking action, getting feedback from reality, then iterating on our mental models based on that feedback.
• Some explanations are better than others. Better explanations have fewer errors, reflect reality more closely, and can solve problems that worse ones can’t. They tend to be hard to vary, and because they reliably account for phenomena, they survive criticism.
• Fit for purpose is often enough. We don’t need the best possible explanation for everything, which is also why the most widely held explanation isn’t necessarily the best one. Often, the simplest explanation that reliably solves a problem is preferable. Only when that explanation fails do we need a more complex or better one. In life, that means we can act on a good-enough mental model rather than continually refining it, which comes at an opportunity costThe lifetime value of the next best alternative forgone when expending life resources to improve or implement misconcepts.Full definition (opens in a new tab)→ (like researching endlessly instead of starting).

These principles are why the advice to change your mind keeps showing up. People in vastly different fields, all striving to make progress, found that being wrong was how they got better, because every mistake forced them to rethink how something worked. And it was often when they were willing to change their mental models that they achieved the success they were after. Whether or not they had a name for it, they were living out the process critical rationalism describes.

We already trust this process, at least in one setting. In science, we accept that hypotheses get tested, the ones that fail get discarded, and that today’s best theory may be shown to be insufficient or faulty tomorrow. That’s how science makes progress.

Yet when we step outside the laboratory, we tend to switch lenses. The beliefs we’ve absorbed about how to live and work rarely get treated as hypotheses. They feel more like facts, so we defend them rather than test them.

We don’t often think of our beliefs about daily living as knowledge. Nobody hands us a curriculum for how to live well, make good decisions or build lasting relationships. We pick these up from our immediate environment, the people we’re surrounded by, and everything else we happened to be exposed to growing up.

But they are knowledge too, and like any scientific theory, they’re fallible and can be improved through error-correction. That’s why we call these mental models misconcepts. They shape both how we experience life and the decisions we make within it, so improving them is how we improve our lives.

To change or not to change

Take the misconceptMisconcepts are the explanations we hold about how the world works, synonymous with mental models but named deliberately to acknowledge their fallibility. Unlike a misconception, a misconcept is not necessarily wrong.Full definition (opens in a new tab)→ many high achievers hold about sleep and rest.

For a long time, getting by on very little sleep was worn as a badge of honour. Those who worked late and woke early were perceived as the committed ones, and sleeping in looked like laziness. You’ve probably heard the popular quip, “I’ll sleep when I’m dead.” This has led to the all-too-common struggle of feeling guilty for resting.

But as our knowledge of the importance of sleep grew, that story started falling apart. Sleep started earning new respect as the foundation everything else rests on, and the cultural norm shifted from championing those who slept four or five hours a night to celebrating those who get a solid seven or eight. Sleep hygiene became a thing.

The new explanation was that our mental resourceThe ability to creatively conjecture, rationally criticise, and focus.Full definition (opens in a new tab)→ is finite. When it runs low, the same task takes longer and the quality of our work drops.

Given the same information, people responded very differently. Those who were willing to change their minds about how to perform at their best put this new explanation to the test, and found that rested, they got more done in less time, and did it better. More hours weren’t the same as more progress. For them, rest stopped feeling like a concession made despite the guilt and became something they did because it’s how they do their best work. But those who held on to the old misconcept, afraid that resting meant falling behind, kept paying for it in exhaustion and anxiety.

From should to want

Most of us have found ourselves on both sides of that divide at some point, quick to update some beliefs and stubborn about others. The stubbornness often comes down to what we believe it means to be smart.

Somewhere along the way, we picked up the idea that smart people have all the answers. They’re the ones who are always right. Under that definition, changing our minds is a small public confession that we weren’t so smart after all, and suddenly our ego is on the line.

The irony is that holding on to this misconcept makes us less “smart” over time, because the mental models we never question never get the chance to improve. So we end up in an awkward position. We know we should follow the advice to change our minds, but something in us quietly resists.

Critical rationalism offers a better way to think about it. If knowledge grows by correcting errors, then finding our own error is the moment it grows. The person who changes their mind has just learned something, while the person who never does has stopped learning.

Seen this way, changing our minds goes from something we should do, despite the cost to our ego, to something we want to do, as long as we care about improving our explanations of the world and, with them, our quality of life.

There can still be a social cost to changing our minds in some workplaces and relationships, but the internal cost, the sense that we’ve failed, fades, because our ego no longer rests on being right but on getting better. This is what we mean by deriving our ego from good iterations. We start actively looking for where we might be wrong, because that’s how we get smarter.

Why epistemology matters

The advice to change our minds is really a call to keep improving our misconcepts. And it matters because almost every decision we make, from our career to our health to our relationships, depends on them. The better they reflect reality, the better our decisions.

Understanding epistemology is what lets us interrogate our misconcepts rather than blindly following the ones we inherit by default, and in doing so, choose for ourselves how we want to live.